Webinar on Climate Change Adaptation: Flooding Part 1: Preparation Resistance and Resilience

Speakers: David Drewe, Dr Robyn Pender, Matt

David: Good afternoon, everyone. Just a quick introduction to myself and Robyn. So I'm David. I'm the head of the Engineering Emergency Planning team. If any of you have been on any of the other webinars, you may recall I was also involved in some of the stuff on building services and climate change bits in the past. I've been with the organisation both as Historic England, and before that, as English Heritage, for 20 years. My background is in building services, but I do get involved with some environmental issues and emergency planning through my day job as the head of team and that does include fire safety and flooding. Hence the reason I'm involved in this seminar. Robyn?

Robyn: Hello and I'm Robyn and I'm very glad to be back because it just cut out on me just then too. Very terrifying, but I seem to be back now. I've been working in one of the sister teams in technical conservation, building conservation issues for about 16 years now. I'm a building performance person with my main expertise in how building materials and systems interact with water. So you can see why I'm doing flooding. I also spend a lot of time working on climate change issues in general, flooding in particular. This is my fourth webinar on flooding. Actually I think isn't it, Matt? But I think we've got some different angles today, on what's a really vast subject, so I'm hoping that even if you've heard me before, there won't be too much repetition. So I'll move this on back to David.

David: Right, thanks, Robyn. Yes, so this is this is the first of two webinars are doing on flooding. The second one is going to be concentrating more on what you do when you have to deal with the flood, that is an actual flood or its aftermath, and that's on the 24th of November. So if you've not already signed up, you might. You might want to sign up, and if you have already signed up after today, you might decide you don't want to, but where we will wait and see how you feel about it. So anyway, it’s the first thing that we're going to be doing over the next few weeks. So first of all, today what we're going to be talking about really is things that you can try to do in advance about flooding, things to try to prevent a flood if you can. And if you can't, how to do all the things that you perhaps need to think about beforehand to cut down any damage or impact from a flood. And as Robyn says, it's a huge topic because floods can happen in so many different ways. And when they do they often involve more than one thing happening at once. So anyway, it helps to breakdown the subject into four basic types of flood. Robyn?

Robyn: Yes, the first type makes the most dramatic pictures like this, it's floods from the sea, which have always been a risk if you live, like a lot of us do in this country, close to the coastline. And of course, we know these kinds of floods are going to get worse and much more damaging with climate change as we get sea levels going up and we get storms, not just getting stronger but more common. And the fact that the water is salty is an issue for heritage as well, not just for the buildings, but for any gardens, landscapes, parks, even for the archaeology.

And another problem is that when you do get a storm or a flood, it causes erosion and that can make the next storm or flood even worse.

On the other hand, coastal flooding doesn't usually hang about for a long time. So that's a good thing. It's a mixture of winds and tides and so that produces a pretty predictable peaks, so at least coastal floods do come along with good warning so you have some time to prepare.

You get a different type of flooding when water courses break their banks. And again it's often related to storminess, but it usually happens when you get storminess on top of a long period of rain, so you're getting saturated ground and the water has nowhere to go. And again this is going to get worse and worse with climate change of course.

But the thing is we've already been constraining our water courses for hundreds of years, pushing them into culverts out of their natural beds, and so the Environment Agency is currently doing some really interesting work on trying to reverse some of those things. In particular what Victorians and wardens did to our water courses like opening up culverted rivers, again as they did recently in Rochdale or even learning from early medieval water management and HE are working with them on all sorts of projects of that sort, but of course it's a long slow process and David do you want to…?

David: OK yes next one is what we refer to as flash flooding. Flash flooding also happens when the ground can't absorb water and that's usually not because it's very wet, essentially because obviously it's the opposite when it's very dry. If you've caught up with the common sense, damp webinars that. We did at the beginning idea with Lyndon, you'll know that when porous materials are dry, they're really good at resisting water uptake. The only problem is that we've built in so many entirely nonporous surfaces, into our cities, and even our countryside, which is why flash flooding tends to be linked to cities and roads.

Drainage then really depends on how good and well maintained the storm drains are. And the answer unfortunately often it's not very good at all. So that's your flash floods. The last one is the full type of flood and it's probably related more to our modern world. It’s is what we call escape of water, which basically means the failure of any water mains or plumbing in around a building and guess you might want to put failing rainwater goods on a building into this category as well. Robyn.

Robyn: So because we always, as you know, if you’ve watched these webinars, before we like to begin with a short quiz. Our little quiz today is which one of these floods causes the most damage in terms of the amount claimed from insurance companies? Is it coastal flooding, or fluvial flooding or? Or flash flooding? or escape of water? And if Matt drags across the little voting thing, you'll be able to vote on this one. I don't think you're going to find this difficult, but I have to admit this quiz is pinched directly from a previous webinar. So real apologies to anyone in the audience who's listened to me before and had this one before. The one thing I can say in my defence is the only thing that's harder than taking a quiz or an exam is actually writing one. Ah, people are doing pretty well, don't you think, David?

David: Yes they are.

Matt: Let's reveal those results. There you go. Yes, absolutely. So, Robyn. The question is, have they got it right?

Robyn: 42% of people have it right.

If we go on to the next slide, we can see. So 60% of claims. It's escaped water that accounts for those, and if you think about it, that must just be the tip of the iceberg of escaped water leaks, because lots and lots of leaks aren't recognised.

They're often attributed to other things like the famous rising damp, but there's a reason why rising damp isn't a term that gets used until 1857 and then we find it as a description of the water getting into the basements in London from the new London sewers. And on top of that, I think it's easy. Pretty easy to see things aren't clear cut because you can have a coastal flood that's backing up the water at a tidal river. Then you get floods that cause the sewers to back up all over the place, and that means when it comes to flooding emergencies, it can be all of these.

There's a lot to think about and to give you some idea of the relative danger from the different types of floods, here's a stately property that's going to remain nameless. Some of you might know it. In the space of a few months, they had two major floods and one was a flash flood that filled the moat and the cellars of the building, but they avoided really serious damage by opening the front and back doors. So the flash flood just went right through and out the back of the house.

The cellars could be pumped out fairly quickly by the fire brigade, but the second flood was caused when a fire hose in the ceiling above the library burst and that caused serious damage, and it would have been very, very much more serious if the House staff hadn't been really on the ball and noticed it very quickly reacted very quickly. Got that ceiling propped up very quickly. They could have lost a large part of that Jacobean plastered ceiling, and with it a lot of very important books. And there's wall paintings on those walls as well. Escaped water is so dangerous because the water's under high pressure and that's something that no natural source of water ever is.

We don't get significant rising damp till we get those sewers in mains, so you don't even see it in Venice actually, and that problem that's made so much worse because we hide pipes away where we can't see them. And we even embed them as we know to walls, which is a pretty dire place for them to be when they leak. So that's the general picture, but what does the UK flood legislation have to say about all of this to help us? And this is back to David again.

David: Yes, well, it's interesting. because obviously a lot of the time people don't think about legislation and flooding, but the legislation is actually quite complicated too. But it's not really aimed at all the building damage. It's often the acts and regulations about other things. But there are so many acts and regulations that relate, but I didn't want to flood our listeners with too much information, so I'll just consider a few of these if that's OK. We can always pick this up later.

I think the starting point really, when you're dealing with floods, is actually the primary legislation for dealing with disasters in the UK, is the Civil Contingencies Act, and in the Act it makes reference to an emergency, which is which you can show here, so obviously, flooding and particularly serious floods and storm damage would definitely be covered by that.

As I said, it's the main primary legislation that then underpins quite a lot of the legislation that goes on from there. So for example we then get the Flood and Water Management Act which was revised in 2010. This refers and only introduces the issues of floods and coastal erosion. And again, I just mentioned the main Act, it gives the Environment Agency the rights for the strategic overview of these sort of things, but again, it doesn't really talk about property. You then get an older piece of legislation.

The Coast Protection Act 1949. Again, this is much older, as it says there, it's about coastal authorities and the measures that they need to carry out to control and prevent coastal erosion, which includes maintaining repaired coastal defences. Robyn’s already mentioned the issues with climate change and so. We can imagine that a lot of those existing defences are probably going to be under strain over the next few years.

You've already then got the Land Drainage Act. Now again, this has been set up to provide bodies that deal with local land drainage and it sets out rights and duties. But it does do with landholders about the potential effect on water courses that they can have. Say for example when getting rid of rainwater runoff and things like soakaways, you just can't. This is the regulation that just said you can't just go about discharging water where you want. Robyn?

Robyn: Yes, this is an example that I came up with that a few years ago when they were first turning over the Royal Naval College at Greenwich to public use and they wanted to turn the crypts into display space. And one of the reasons we were called in was they were getting occasional flash floods running off the car park, which is to the left and down the slope to the door, which you can see pointed out with the red arrow. They didn't want to pay to resurface the car park to make it permeable, which was the obvious solution. But when I suggested to them that they then had to divert that water into storm drains away from the building, they explained that it was going to bring them over their discharge limit for the site. I'm not actually sure what they did in the end. I hope they dealt with that car park, but you can see it can be a real problem for these big properties.

David: OK, yes, yes, that's a good point. As already mentioned briefly, a lot of the legislation that you come across to do flooding, particularly things like the civil contingencies and stuff like that is really dealing with the response from what we call first responders. Social, local services, fire rescue services, the environment agencies and all of the bodies, and it's about how they are required to set up and manage and deal with a disaster or something that could be a flood.

Only very rarely do you find that there are duties placed on individuals or owners. There are bits and pieces in the regulations, probably the one that's quite different from those is the Reservoir Act and, and particularly if you've got a large property, you need to be aware of your responsibilities under this act, which is really set out to say how you deal with the possible or sudden large deluge, say from a dam or contained piece of water. The act is broken down into two parts. The first one is for any body of water holding more than 25,000 cubic metres of water above ground. And there are strict rules and regulations about what you need to do with that. And then there are also rules about smaller reservoirs than that, but again, it's something that people need to be concerned because there are very clear rules and regulations, and you can get some into trouble if you don't think about these things.

Now again, I mean a lot of us probably actually understand what we mean by reservoir. It's sort of stuff you see, maybe in the Lake District, which is massive, large bodies of water, but it can easily include things such as this ornamental lake or pond within a park or garden. If it goes over that criteria that they’ve set then this would be classed as a reservoir and you need to comply with the act. Again this is an example of a site that somebody might know. This is this is Tilbury Fort, and before it is the River Thames, but the moats that surround it on three sides actually fall into the requirements of the of the Reservoir Act. And so it's something that you would need to consider as part of any flood management plan. These are some of the points that you need to think about from the Act, and as I said, you can be held responsible for damage or injury caused by a sudden uncontrolled release and you can be prosecuted because you'd be breaking effectively an Act. You can be prosecuted and the main things for really for people that maybe get involved with these sorts of things is the ‘You Musts’ there. You must prepare a reservoir flood plan and a flood map and you have to report any failures or potential issues that you might have. When you're maintaining a reservoir.

Robyn: Is that reported to the Environment Agency?

David: Yes it is. I mean what you'll find under the Civil Contingencies is you have a local resilience forum which is made up of the various bodies, including the Environment Agency, fire rescue people and they would be the people that you would liaise with initially when you draft up your plan to ensure that they are aware of any risk on the site.

The interesting thing though as well as even a site like Tilbury, which as I mentioned, is on the banks of the River Thames. The moat itself holds obviously a large amount of contained water which is classed under the Reservoir Act and so is seen as a risk. But this map actually shows you the flooding risk around the fall. I hope you can sort of workout from the previous photograph. The fort is in the bottom of this slide. At this slide, but the red area which is shown above is the is the potential flood risk area around the fault. But that actually is a flood risk area caused by flooding that will come from the land side, not from the from the river, or actually a failure of the reservoir. So even when you think there are some fairly obvious risks, such as being next to the River Thames. It doesn't always end up being the most severe risk from a from a flood point of view.

Matt: David, there's a quick question here in the chat, wondering if there's a simple diagram that explains which agency/authority is responsible for what.

David: Well I would say there is a diagram. I mean each area has this resilience forum and that will give you the makeup of the people in there. The regulations. If you go into the government's website and look up your regulations there also on the government’s site, there's lots of guidance that they produced, advice books and guidance on regulations and when you go into there it does. It does breakdown the various tiers of first responders. There are some good guidance documents that have been produced by government on this and in there it will show who are what they called tier one. I'm not going to mention too many tiers because we were all in tiers at the moment. But you know the various VSO, you’ve got your tier one responders which are your first responders which are the ones that we think of, obviously. But then you get down into your second level responders third level and even organisations, such as some of the Saint John’s Ambulance. Another sort of people that come out, the international rescue type organisations can sometimes be involved in it. So if people want to, what I would start with is going on Google, looking at the government website on civil contingencies and following that through and it will breakdown who the various agencies are.

OK? OK. Right, so what did we get to? So that's the Reservoirs Act, just some points on the Reservoirs Act. The other thing I thought I would mention is there's a piece of regulation called the Flood Risk Regulations. And in there they include some definitions of what a flood is. In this place they say it's any case where land becomes covered by water. And they don't actually explicitly state what is the cause, but they do. interestingly, say what it doesn't include. So for example, they say in there that a flood or in these regulations isn't flooding from a sewer unless it's obviously because the sewer itself has been overwhelmed, by a storm or a reservoir bursting. Or essentially, it also doesn't include floods from burst pipes or water mains, but it's interesting that because we mentioned right at the beginning of this, from the insurance company's point of view, the biggest claim that they deal with the most claims they deal with from an insurance point of view is actually floods from existing closed pipes and floods from each drainage. But interestingly though the actual risk regulations don’t recognise that.

Robyn: Yes, I guess that might be because they're trying to protect the big players. And these water companies are just never going to admit liability. That's OK if you think you've got a leaking main that's causing problems, and I can tell you that really is the usual reason. When I get called in for rising damp, it's pretty much always this. So here this church in London, the Scottish Church, where I got called in because they had rising damp. I think you can see that in the middle. Well it was. of course, a leaking water main. What you do is you ring the water company and you report a suspected leak and they'll come and dig it up and they'll fix it. But they probably won't tell you that they've done it because they don't want to admit that liability, but as long as the leak stops, who wants to be picky? This is the way of getting it stopped, and they will stop it.

I should probably mention too, that water companies really aren't thinking about leaks in terms of where that escaped water goes. For them, it's really just about loss of flow through the pipes, because that's what they have to account for. So you really need to be aware that not everyone involved in these things in dealing with the leak is going to be coming to the question from the same angle. So we'll be saying to them, We don't want this water and it won't have occurred to them that that's a problem for us in many cases.

David: Right, so I suppose the trick really is what we're trying to say in this seminar is trying not to get caught out by a flood and so to do this is, the best you can do is try to plan ahead and that really means understanding these three things, and that's obviously understanding the risk and this include things such as: What's the sensitivity of your building? Also, how sensitive is whatever it is that you're doing, so the risk is not just the obvious stuff, but it's about what is the building doing? What are you doing? What can you do to head off a problem at the pass? And remember that it's very unlikely that they will just be one. There is more likely to be several. They could be independent on actually all working together.

Robyn: Yes, it's really unique to the site always. That's why every site needs its own site plan. And if you're changing building use, that also means you'd need to change the plan. Yes, that's quite right. Yes. So understand the risk. Is it unique? Is it unique to your site? And from what that what we mean is, it’s not necessarily that serious. That's, for example, I would just say, where we are. It could be that it is unique. I mean, since you want to understand that you know something is not necessarily serious. So for example, a major storm can cause massive damage, but if you're not by the shore….

[They discuss slide order in the presentation].

David: So OK, you need to think about this risk, its likelihood and potential damage. So again, you need to consider the chances of something happening. Then what the potential damage is. So as I said, if you've got a major storm surge and it has to do with a coastal incident. Obviously if you are not on the coast, then obviously, that may not be something that you necessarily can need to consider, but of course we have to bear in mind with coastal flooding. This comes with the big red warning that we've already mentioned for climate change. With sea levels rising in coastal areas, we're going to see properties that probably start to suffer that may have escaped flooding in the past. And so, of course, it might not be possible to move many of them, and in some cases the flood contingency might even be that we just have to include a record and then we get prepared to lose them. Yes, I think that's one of the issues.

And of course the other issues can stay on coastal is that, just thinking while we're talking, is that a lot of the measures that we're putting around London is to stop surges up the River Thames. So London is actually some ways a long way from the coast, but of course you get this knock on effect as we get storm surges so it can be an issue.

Right, so back on track now. So yes, as we said, fluvial flooding can be very like localised and you can download flood maps. You should really be trying to learn from your local history as well. For example, even in a local on a local flood map you might find a building has never flooded but another just down the street might flood all the time because you do get these peaks and troughs are all over, even in a local area. The maps are good, but you could still use other information to find out the property of owned buildings.

So again. it’s this thing about climate, climate change and land use change. Those two things come into effect as well. So let me get in flash floods. I mean this is even more of an issue. Flash flooding is something that we're seeing more and more in recent years. And combining these impacts of land use changes and changes in rainfall, wind, I think it's going to become more of an issue with definitely lots of places. In the last few years have been inundated with flash flooding that maybe in the past we have never even considered experiencing the sort of levels of flooding or rainwater that there have been, in the last maybe ten years. I guess we can all go back and see things in the press about stuff like that. I think with flash flooding that's one that's probably much more difficult to plan for because I mean it can occur in effect, anywhere, but there's still some things that you can do to try and alleviate that.

Robyn: But if we give an example of that. Well, I almost said what the property name was. The stately home I mentioned that had the flash flood head down the drive and that came out of absolutely nowhere on a fairly fine afternoon because in the morning there had been a rainstorm that hit a nearby hilltop where the farmer was growing turf and had just removed the turf and the came straight down and headed straight for the house. They'd never seen it before. I don't think it's happened since either, so flash floods are very, very hard to plan for.

David: Yes, and as I said we’ve got escaped water. Again, the escaped water is important, not just directly, but because wet fabric is much less resistant to other types of floodwater. The best way of flood proofing the building is to maintain it well, which leads to the next step which is… understand the building. So you need to understand the building and it might interact with floodwater. Just like the flood risk, the risk of damage is going to be unique to that building.

Robyn: Yes, absolutely. So for a start you've got the condition of the building. Is it well maintained or not? And if you've already got problems with your rainwater goods and roof, and so then in a big storm, you're going to get them failing on top of everything else. Then there are the types of materials that you've got.

These are going to interact with floodwater and with different types of floodwater in different ways, so an earth building might resist a flash flood remarkably well, but it could be seriously damaged if you've got something like a slowly leaking heating water pipe and the way the materials are put together, of course, really matters too.

And some structures are just much more robust than others, and some can dry more easily if they get wet. It would be interesting to do a post-mortem on this one. It looks like quite a number of things are going on at once and that's why the damage has been catastrophic. There's a film of this going. It's in Hawick, Scottish Borders Country, and it's quite a shocking film to watch this corner of the house and the building go. But they just had building works, which is always a little bit of a red flag, but I think basically there is scour underneath. It's but several things happening at once.

And then on top of that, the final piece of the puzzle is really important too. It's what you're using the building for, and that's because some uses are also much more insensitive to flooding than others. So for instance, it's amusing, or I should say perhaps a bit bemusing to me, that a lot of large building owners want to put their archives in the basement and the attics of the properties which are the two places that are going to be most at risk from flooding. And in in the same way that in a house everyone wants their kitchen to be on the ground floor. Even if they live in a flood zone. A friend of mine who lives in Venice though, tells me that traditionally the ground floors were only ever used as empty reception halls and until recently, there was a ban on having ground floor apartments in her place. They never have furniture that they can't carry upstairs on that ground floor.

The history of the building tells you a lot about this. If it's always tended to flood, they're going to have been prepared for it. They're going to have predicted this and built for it. It's wise to follow on from their lead, so now how good are these old buildings? They have stood up very well. We have these marvellous modern building materials and building systems now. They absolutely are better than these old buildings at shrugging off flooding. Well, to answer a question with a question, we've got another multiple choice for you. Which of these two buildings (the A is meant to be on the building at the left) has suffered catastrophically from the big floods a few years back? Was it the fourteenth century Merchant Adventurers Hall in York, or was it the Civic Centre in Carlisle (twentieth century as you can see in here)? Here's your chance to vote. Which of these two is it? Well done, that's exactly right. Yes, I think I think that was that was very quickly voted for. So we can go on to the next one, Matt. I'll just… there it is. The Merchant Adventurers Hall just shrugged the flood off despite there being a hidden floor in one wall that let the water in that they fixed that floor now and they expect it to do even better next time. But the poor old Civic Centre has been or is about to be demolished. They couldn't get the water out from all those gaps in the curtain walls and in the end they opted to get rid of the whole thing, which is rather a pity. And it's a worry about the White Paper on planning that it repeats this received notion that modern construction materials are inherently more robust and sustainable when, of course, what we find all the time in doing our day-to-day work, working with buildings as they meet things like floods, we find that the absolute opposite is the case. So our ancestors knew what they were doing.

David: OK, so thank you for that. We're getting into our third step now. It’s this thing we call prepare. So that's really to take what you've learned in steps one and two and use it to prepare a unique plan. For your unique case and you might find you need to do very little beyond good maintenance. So you might or you might need to do some drastic rethinking, especially if you're at risk from climate change. I'm sure looking at those two, you had a picture on the left, that's the one about looking back in history and looking at the building doesn't really suffer with flooding, although all around it does. And of course the picture on the right is an extreme way of getting yourself out of deep water, I would imagine.

Robyn: I come from Queensland, where everything is like that. Anyway, it's about preparing. So the first thing to remember is that that you can't do a lot on your own to deal with the local flood risk. There might be a lot you can do if you work with your neighbours. The national flood forum, for example, is really good at helping people to work together. And local flood groups are really good at identifying local risks that the Environment Agency may have missed and at figuring out ways of dealing with them. So, for example, working with local farmers to find ways of stopping runoff safe from flooding from fields are good examples there. So we also then need to think, when you're thinking about your property, and the possible actions that they really fall under two categories. And though they aren't mutually exclusive, you can think of these as one is where you're trying to keep the water out, and that we would refer to as a building that's resistant. Or are you trying to make sure that any water that does get in does the minimum amount of damage? and that's the resilience. And with climate change making flooding worse and worse, the Environment Agency has really started to lean more towards maybe that we should be looking to make buildings more resilient.

Robyn: That's really true, but we'll start a bit with resistance because if you can, you can keep the water back well away from the building, that's obviously terrific. But the key to that statement is, if you can, because that's going to depend on where and how you flood.

This is the perfect example. It's Saint Lawrence in Appleby, in Cumbria, and looking at the map of where it is in that bend in the river, you won't be surprised to hear the church is always flooded right back to the time when it was built, but just before the big Cumbria floods they spent £50,000 to put in a bund in the churchyard, a dam as it were. It's a raised earth wall around the church in the graveyard. I'm really not sure how they got permission to do that because it is grade one listed, but the lovely vicar who took me down to see it a few weeks after the flood was explaining to me, as we walked down the hill, very sadly that they just made the bund just a little bit too low because the water came in over the top anyway. But when I asked her to describe to me how the flooding actually happened, exactly where the water came through and into the building was at the front door, she said, ‘Oh, it came up through the floor as it always does.’ And if you think about that alluvial structure in that river bend, that's really no surprise.

You really can't build a wall that will keep that water out with something. When you've got a situation like this, at least you couldn't unless you dug down a very, very long way. But what the bund did, alas, was to stop all that floodwater running away again, so the church was wet for much longer than it usually is, and this was the result. They had stone decay and corrosion and other damage the like of which they've never seen before, and that's not really what you want at all. So a bund might sound innocent, but it isn't necessarily the case.

And even when they're in the right position to work, a lot of the experts do insist that they have an escape port. So if water gets in behind them, you can get that water out. So if for one reason or another you can't keep the water back from the building, the next step is to try and keep it out from the building itself from the inside of the building, so stopping up the points on the envelope where that water might get through.

And that's not just the obvious ones like the doors, but the many less obvious ones like the air bricks. And if you're lucky enough to have a solid walled building then, unless the walls are really sopping wet like you've had a gutter leak that's gone on for years, they're going to keep that water out pretty well and we've been finding that in our tests that Sheffield Hallam. We’ve been flooding through full sized sections of wall, and when we did it with a cavity wall of engineering brick and cement, the water just went straight through as if it weren't there. But the 9 inch wall of handmade brick and lime barely got damp on the inside face, even after more than 8 hours. I was here for this test and it was fascinating. You could touch the wall, you could feel it was a bit damp, a bit moist, but there was no more water trickling through at the bottom. Then you can see there's a little bit there, it would not. You would have been able to even stop it damaging a wooden floor, though you wouldn't counsel you having a wooden floor if you were in a flood area. But if you look at the photo on the right of this, you can see that that brick on the bottom is still quite dry in the centre.

Well, that was one of the poorly fired handmade bricks and from our driving rain work we already know that lime renders are just brilliant at keeping out the rain. So as soon as we can, we're going to be trying them out on floodwater as well. And I'm wondering if they could help us even rescue things like that cavity wall, but that's for the test to tell us. it's just that I'm hoping that will be the case, but clearly when you see these bricks, the low fired bricks are more resistant. A lot of the preconceived notions of how water transfers are not right. Actually, these materials are very robust, even if they look soft.

The problem is that now so many people have forgotten how those old porous materials and systems work. There's a lot of push for things like sealants for brick and for other traditional materials that you would seal with this magic modern substance. But alas, with the traditional ways of doing things like renders, they're not like this at all. And if anything, when you put on a coating, it actually stops the natural system from working. And if water gets in behind the coating, then the resistance to evaporation means you get things like salt trapping, and that leads to clay and lots of surface. So you know that can be because the water gets through in the flood and then is drying out. But it also can be all the other ways that you can get water into that wall, including gutter leaks and plumbing leaks. This is really common damage. I come from a wall paintings conservation background and, if you like, all of wall paintings conservation is how do you keep something on the wall that's changing the porosity of that surface? And if water gets in behind, what happens if the wall painting peels off? It’s very hard to fix up, so this is not something you would do to a porous material. If you want to know more about this, you can listen to those common-sense damp webinars we did at the beginning of the year and I'll talk a little bit more about it in Part 2 of flooding emergencies as well.

David: OK, thanks, Robyn, and of course the other thing we do now that we perhaps didn't do so much in the past is we have we bring lots of things through holes in walls for pipes, cables and then we say we put damp proof members in and things like that. Generally it's really hard to sell the property because no matter how hard you try, you get an imperfect seal. So around these and they can actually sometimes act as a siphon drawing water in.

Robyn: Yes, the tight joints are often worse.

David: And also, and particularly, a lot of these are now even hidden and below ground, so you don't always necessarily know where they are.

Robyn: I think that's a problem for our old buildings too, because people don't want them to don't want new additions to be seen, so they tuck them in where they can't be seen that they cause a problem that didn't exist before.

David: Yes, and of course one of the weakest links is plumbing. I mean we connect our plumbing systems directly to the drains that can be overwhelmed. Particularly, say, at the bottom of a hill or in an area that's prone to flooding, and so it’s things like that that you need to consider. But of course because there are things you can do even with that, try and stop all the different ways that water might get in. Say, for a back flow from a flood, but finding it can be tricky, especially if you’re in a hurry. So it's probably safest, for example, and that's saying that you don't see that it often is. For example, long bells in your drainage systems that can sometimes prevent that. The only good thing that I’d say about that is, obviously at the same time, if you put something like that, you need to be able to get to it to look after it and maintain it, because obviously they might need checking on a regular basis.

Robyn: Yes, especially when they've got the swing doors, that can get trapped.

David: Yes, so with all of those problems, you might be able to see why in some ways people like the Environment Agency are encouraging people to think of resilience again. Our modern houses particularly are much less resilient than they were in the past. For example, if you can compare these two, kitchens, both providing in some ways to some function. But obviously the kitchen on the right, the new one. If that was to get 300 milimetres of water flooding, it would be quite devastating. Whereas with the one on the on the left, it's probably easier to recover from it. The floor is probably more resilient. Most of the furniture you can move out the way reasonably quickly so there are some lessons which may be to be learned from that. And as I said, there's lots of advice out there on how to improve resilience, and, for example, electrics. Think about when you got electrics in particular and where to put socket outlets. Make sure you know it you know of a flood area and you know the likely levels of flooding, install the electrical sockets above that level.

Robyn: I do them high anyway. I don't like squirreling behind the sofa to try and find a power point myself.

David: Yes, exactly. So even if you're not in a flood plain area, it's a good idea to think about this whenever you're planning a redecoration, so you don't have to bend down on the floor so as you get older and have to plug things in.

Robyn: Especially since we plug our entire lives in these days.

David: Exactly. So what I would say is the thing about planning ahead is it can make all the difference and, for example, and particularly, learn from disasters and then feed that back in and that's the whole principle about emergency planning. It's that you try to prepare, if you have an instant, you respond to it and then from that you learn, you recover, and you feed that back in. So that's the basic principle of have emergency planning, which is what you need to do.

Robyn: So yes, I think that's the key. You need to think about what needs to be done, and then how are you going and then obviously by whom? I mean, who's going to do it? It's the whole principle around how to deal with an emergency.

Robyn: It sounds tiring until you get an emergency.

David: Yes, but the one thing I will say if any of the listeners are involved in something we call larger scale emergency planning is it's all very well having all of the plans and all the ideas in place.

You do you really need to try out and you need to practice your theory just to see that you can actually do it in reality. And that side is what we do on that on our salvage training courses. We do actually teach people the theory, but we give them a nice soaking and we give them some practice in how to try and deal with floods and so that's something we do.

But what I mean is some of you might be thinking when you hear about big emergency plans and stuff like that, Well, actually that's great for large organisations.

But it can be sometimes just simple things, even on a domestic level in your own home. How many of you actually know where to turn off the water supply to your home and how many of you actually make sure that it works? I mean, often you'll find that one of the problems you’ll get is that you know where to turn off the stop valve or the stopcock in your house and it's not being used for such a long time. You can't actually turn it off. And then you got your rushing around trying to find out where the next fruit likely place is and you find it has been covered up in the garden because you have decided to cover it with a flower bed or something like that.

So even if you're not really looking at what I would call major emergency plans. Just simple things. And don't forget, also, you do not only need to think about how to isolate water supplies. Perhaps you should also think about other things such as other utilities that where to turn off the gas, how to turn off the electrics safely. You may have been a location where you don't have on grid gas supplies, so you might have to store large quantities of, say. fuel oil. How do you turn those off? And, of course, there's also always a risk that the oil tank themselves could fail, and then you could have a flood of a slightly different nature. It wouldn't be water; it could be some other liquid that can be perhaps just…

Robyn: Much, much more damaging.

David: Yes, much, much more damaging. Exactly, Robyn. And of course, when I said about training, it's again simple things. We all see the images on the TV of the local authority turning out with bags and bags of sand and everybody is sticking sandbags up. And yes, basically yes, that's alright but more damaging to you. You do really need to practice these physical activities so you can get it so you can get it to work. So sand banking for example, seems and sounds interesting. It's simple, but it's a team effort. You need to practice as a team, particularly if you’re doing it in a large area. For example, it’s things like sandbags no more than third full or can you shift them? Can you shape them? You know if you make them too heavy, people can't pick them up. You know plastic sheeting is alright.

Robyn: So you can’t get a good seal with them.

David: Yes exactly. Plastic sheeting is waterproof.

Robyn: It’s not the bags keeping it out, it’s their holding in place.

David: Yes, exactly. So it's things like that. You know you need to lay up the bags a bit like bricks, tucking in the ends under and staggered in rows and kicking them down as you go. So it’s the whole thing about how you just go through. So it’s the whole thing about how you just go through. These are stills from a training film. When I tell you where it’s from, you can guess where they’ve come from. It's from the Queensland State Emergency Service and you can watch these and others online, but nothing beats actually doing it. So if you if you are responsible for larger planning get yourself in a separate team, get out the materials and go in and practice so that when you need know what you're doing. And that’s exactly what you do. And as I said, that's what we do. As I said, we do a training course for people, and part of that is on flood management as well. We don't deal with large flooding, but we deal with what we would call escapes of water. Robyn?

Robyn: Yes, we're talking more next month about what to do when, despite all your best efforts to keep a flood away, it hits you because then you need to go into recovery mode and so that's the subject of Part 2 and it will be on the 24th of November and in the meantime we have lots of other webinars, past and present, which you can watch live or on recordings. (Sorry, more on the slide).

So you've got the link. You can watch these all past and present on the Technical Tuesdays page and we also put out lots of written guidance. It's being updated all the time. We do know, though, that our website is really hard to navigate and so that's why we produced this technical advice booklet. So if you download that as a PDF, it has all the hot links to take you straight through to the right page. Includes web and R hot links, and so Matt's posting a link to that, I think, in the chat space. He has done so.

In case you don't already have it, we've also started a technical conservation newsletter which goes out on the last Tuesday of each month. And that will keep you up to date about all our new technical, specifically technical publications and training. So not the general publications from Historic England, but those of particular technical importance. And Matt's going to put up a window that will let you sign up to that now. And don't worry if you're not sure whether you've signed up already, Sign up if you're not sure. We’ll only send you the one email we don’t do double checked names. If all else fails you can also drop us a line at [email protected] and that’s our one-stop e-mail for technical queries so they can be passed on to the right person to get you the right answer. But we do actually have some time left, so we would both be delighted to answer some questions now and I thought that some very interesting ones had come in on the chat actually. Let’s see.

Matt: I've got them all down here, actually we could work our way through them. Thank you very much for everyone who's asked to sign up to the newsletter as well. I'll move that away. Also someone mentioned that they rather liked your diagram for flood resilience.

Robyn: It’s not my diagram. OK, so there you go, if you'd like to download the diagram which is there, just click on the diagram that and you'll see the download button will appear at the bottom of that window. Also we can bring this window in so if you have any questions you'd like to ask David or Robyn, please type them into that Q&A box there. There you'll see the text box at the bottom of the window and we can. We can view your questions as they come in. But whilst we're waiting for you to frantically type your questions away, we have a few questions already from the chat. So firstly, are you aware of increasing issues with basement floodings in large towns and cities as a result of increased water table levels, as a result of increased development, reduced amounts of land for water runoff. Forgive me if I read that out badly. I hope it makes sense.

Robyn: Well, yes and no. I think that we do still see problems in areas that have always had problems. It's interesting, for example, that under your cathedral when we looked at the water table. The water runs in the different strata in different directions. It can be very complicated. And so things can get disrupted quite easily. I don't know so much that it's reducing the amount of land for water runoff, but reducing where the water runs too. And of course, if you're doing major developments and people do these deep foundations now, they will be disrupting the normal passage of water. But, in truth, the majority of basement flooding is usually traceable back to leaking mains and sewers. They use a lot of water and the water companies, for example, don't consider it a serious leak, unless it's losing more than 30% of the flow, and that's a lot of water and gunk that's getting into our properties and that is something we're trying to raise awareness of with the water companies at the moment.

Matt: But there's a quick question in the chat that’s just come in, which is very close to my heart, living in a rural area. Do farmers have a legal responsibility to maintain their ditches?

Robyn: Oh, good question.

David: The only thing I could say, there, is obviously as I mentioned earlier, there are some rules and regulations about controlling runoff from land into water courses. So I'm guessing it will be one of those things where, if it could be shown that through poor maintenance of that they are, for example, instead of the water being channelled the way it should be, it's now allowing runoff into, say, streams and rivers that it shouldn't be. Then that would be a reason for someone, probably the Environment Agency or someone to get upset. Particularly important on farming if they're using chemicals and pesticides on the ground and it runs off into streams.

Robyn: Yes, Giles has put up.

David: I would imagine mostly that it will be things that will be seen as a consequence rather than a direct thing, it would be for the person to manage the land and then if they fail to do that.

Matt: Indeed. Thank you. Let's move on apace because we have very little time left. One question here regarding Historic England. Responding to the planning white paper in terms of flood risk, I think because the white paper is still in consultation, we're not allowed to comment, I think I'm right, yes?

Robyn: I think that is probably right.

Matt: Yes, so many apologies for not being able to respond to that question, but I'm sure you could understand our position currently. Moving on, I wondered if anyone knows how the amphibious house on the Thames was performing. I remember that for a rather well known television program they built a house that actually floated. Yes, which was OK. It's a houseboat, maybe, but it was a tethered one, and it was very clever. But yes, I remember that one. I'm not aware. I would hope it's performing extremely well.

Robyn: It is a boat, isn’t it?

Matt: Oh, it's essentially a boat. OK, so does Historic England have a view on the creams that are also claiming to be microporous or breathable. I tried to resist their use, but homeowners regularly bring them up as they appear to be successful in the short term.

Robyn: It depends on what you mean by successful. When you don't have a flood, you don't have a problem. So if you put if you put a coating, whether it's a cream or anything else on a wall of water, it is something that changes the porosity. So the water is not going to get in. It's not going to entirely stop the water. They don't claim that it does. They say it stops 90% or something like that. Now it's probably less than that that it actually stops on a real wall. They do the testing on small blocks. They don't look at joints and so, but even if it were 90, you've got to think that means there's still 10% getting in. And it's got to get back out again through that coating, and that's where you get this real damage and unfortunately what it means is because you're building up the moisture content, what you're doing is actually making that wall less resistant, not more resistant, because the drier the better for the material. So what you do is take a system that actually works and you stop it working. And if you want some more details about that, have a listen to the two common sense damp webinars from January and March, isn't it? And they take they go into that in quite some detail.

Matt: And they are on our website, if you care to go and have a look, you'll notice I put another little window in the web links with three web addresses there. If you actually click on the word webinars or advice and guidance you'll see the URL appear at the bottom of that window. So on the webinars you'll find those flooding webinars. So next question, the problem is how to convince the market that traditional products are better. We are constantly fighting this battle with householders. Some of us know this stuff, but there needs to be a publicity campaign by HE or something or someone to raise public awareness. Well, yes, I think that's more of a comment than the question.

Robyn: I think so too, but I think it's a very wise comment and it is something actually that's so far up the agenda for us in technical conservation. I think that we're also coming to those conclusions that it really needs a push on it. Unfortunately, what we're pushing against is the number of companies that make a lot of money. It's interesting that people would rather trust someone who makes money out of something than us. But there you go, but the physics is very obvious. The reality is very obvious. We can see all these things, but you're right that it needs perhaps a campaign to make people again feel confident about how old buildings did it, and that goes on, yes?

Matt: We need the construction industry overlords, as it were, the governing bodies of the construction industry to buy into that agenda.

Robyn: Yes, if you can get them using these materials. They do see how it works and how big one is really on the lime plasters and renders. I notice Joyce is asking about that. Lime renders, the work we did on damp towers, showed unequivocally that even when you had a whole wall that was very, very void. All you had to do to make it resist the water, and indeed to dry out from having been wet, was to put renders on it. The buildings were rendered, we even see tapered brickwork buildings with render, that were rendered afterwards, probably when they started to fail when the joint started to fail they rendered it with lime, not with cement, it has to be it the way it works. It depends on this porosity and permeability, and so the very opposite of what people think. You don't want to make it less permeable. You want to draw on that permeability and they work extremely well and, as I said in the talk, I'm really curious to see how well they work when you put them up against floodwater, it ought to be just as well. We will be trying that over the next few months.

Matt: OK.

David: A few other things on the construction side. There's also the speed of construction, now the construction world wants things to go out as quick and as fast as possible. You know, a lot of the techniques that developed have been around. I think that's their principle, isn't it? It’s the speed of construction.

Robyn: And idiocy of construction, I have to say, because the old builders were very skilled but building is no longer a skilled craft. And that's a real pity because, in the past, you learned from your mistakes. It’s back to your diagram for emergency planning. You won't get any good unless you're there, revisiting what you've done, seeing what works and doesn't work. And unfortunately there's no system for doing that anymore. That whole feedback system has gone.

Matt: OK, let's move on apace. I did note just very quickly that someone has said in the chat that we have beavers in the Forest of Dean, which is slowing the flow into the Wye River to reduce flooding in a village on the river. Yes, absolutely, yes. More beavers please, absolutely. We’re all for that. So another question, what are your thoughts on the Telling Unilit lime plasters, renders and similar that claim to be good for retaining walls? I assume that's a product, Telling.

Robyn: It's a standard lime, Telling make lime. I don't know what they're adding. I would be tempted not to add too much. That's another thing that will test when we've done the plain lime wash. We can then test various additives to it, but the additives weren't very much used in past. They did limewash, but there wasn't a great deal of adding additives when you go into the past to make things waterproof, and when they did they tended to fail. There was an attempt with the Houses of Parliament to use bitumen and it failed. So I think people were aware that the traditional things worked. So I've got lime on a retaining wall and it's a very fine shade of green but I thought it would just drop off and it hasn't. It's fine. It's actually standing up much better than the cement.

Matt: Now here's a very interesting question. Insurance companies are dictating repair and reinstatement specifications. Is Historic England talking to insurance companies about special materials?

Robyn: Oh, yes we are. You bet we are and we are involved in the DEFRA Flooding Roundtable. The trouble is that the insurance companies on that are just as aware as we are about the benefits of traditional materials. One of the people is Natalie Lloyd, the technical director of the Concrete Institute and she's even more so. She stands up there and she says, Cement is a wonderful material for many things, but renders aren’t one of them or plasters. Do not do this. So the trouble is, of course, when you get the people who aren't around the table you always have a problem of talking to the converted but we keep pushing away. We get a lot of help from the National Flood Forum who are brilliant about this, but it is about getting through to people how the traditional buildings and systems were meant to work.

Matt: James mentions grey coats rather than overcoats. Don't get Robyn started on grey coats and raincoats. James mentions that Unilit, he thinks, has some cementing it. Oh, so there you go.

Robyn: I wouldn't go there. Why bother? It works without. We have a tendency to be scared of the works with that.

Matt: I know we've run over, but I'll ask a couple more questions. I wonder if our farming practices are going to change after Brexit, which might reduce the amount of pasture coupled with the spread of housing development. I think that was actually a question asked of one of the other attendees.

Robyn: One thing that might be interesting to point out at this point is one thing that we've been talking with the BGS and the Environment Agency about. With old farming practices was how the old hedgerows and field boundaries actually worked. The hedgerows actually are better than a French drain. They actually, when the water hit them, they tended to go down. So that already cut runoff and they tended to be positioned in a way that stopped the runoff anyway, plus they were positioned where they could plough the soil back up again because it's about loss of soil as well. And so they were put where they would gather the soil and then when it came to ploughing they ploughed it up to the top again. So there's a lot to be learned there as well. Again, they weren't stupid.

Matt: Indeed there are many, many of the more ancient and arcane practices which that they've been doing that for a long time. So they figured they were for good reason. I'm just looking through and there's another question, but I think that's for the next session. Saying there's an issue of convincing the insurance companies, and their surveyors, which is perhaps absolutely right.

Robyn: That's why we're doing all those tests too, because being able to show how a full scale wall actually works, is much better than anything you can say about the science. You’ve got to show it.

Matt: Absolutely. Fantastic. I think we've pretty much responded to all of your questions. If we haven't, please say so, we'll have a look at some more. If you're happy to hang around, but I note that we have gone overtime as we always do, so apologies for that.