River paid a visit. Lots to fix. Some questions!

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Roger440
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Joined: Fri 7th Feb, 2014 1:48 pm

River paid a visit. Lots to fix. Some questions!

Post by Roger440 » Tue 29th Dec, 2020 7:50 pm

Sadly, on the 23rd, the river decided to pay our house a visit. Not quite the christmas i had in mind, but here we are.

it was always going to happen sooner or later, but its happened now, so the work i wanted to do has been brought forward.

Keeping it as brief as possible. Front half of house, early 1800's cottage. Brick, 9 inch wall. Back half 15 years old, conventional brick/block construction.

The front half, i already intended to remove the gypsum plaster (well ive already started prior to this) and some form of limecrete floor. (with a sump pump system of some sort)

Now is the time to make it more resilient to flooding. So lime on all the walls, as it will be coming off in every downstatirs room.

However, nice insurance peeps are saying the floors in the new part need to come up as they are screed ontop of insulation board, on top of concrete. They suspect the insulation layer not to be waterproof, so out it must come, to be replaced by waterproof version such as EPS. They pop a screed back over it and tile.

At which point i start to ask questions.

Would it not make sense to use a lime screed? So any water that gets trapped in there can, ultimately find a way out. Thoughts on this idea?

The intention is to tile the whole ground floor, so along with walls that will dry out, we can wash it out and continue living. The flooding is fast, quick, and with a submersible pump can be maintained at approx 1.5 inch depth. As the river/brook is a very small tributary to the ouse, this is what it does. Long periods of standing water are basically never going to happen. We are too far upstream.

Accepting the above, what im struggling to establish is what material the tiles, flags etc should be for the underlying lime screed to work, be it over insulation or foamed glass(front of house). I.e, it needs to be breathable. I assume i cant whach down cermaic tiles for example?

Ive also the challenge in the new part, that i cant put down anything to thick.

All thoughts welcome.

Lime
Posts: 2743
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Location: East of England

Re: River paid a visit. Lots to fix. Some questions!

Post by Lime » Tue 29th Dec, 2020 9:43 pm

The first thing I'd do is drill a large hole in the new concrete floor and find out what the insulation is actually made of.
The insurance company may be worrying about nothing.

YorkshireCottage
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Joined: Sun 22nd Nov, 2020 4:04 pm

Re: River paid a visit. Lots to fix. Some questions!

Post by YorkshireCottage » Wed 30th Dec, 2020 4:15 pm

It sounds like you have a combination of flooring which may complicate matters, particularly from an insurance perspective. They seem very keen to make house "waterproof" rather than breathable. If I was in your position, I would read this:

https://www.heritage-house.org/

and contact them for advice, as your insurers may not like the concept of potentially removing concrete to lay something breathable and, by definition, water permeable. You may need the help of experts to argue your case.

Sorry I can't offer advice on the type of flooring - stone flags seem to be the preferred option in my area where some houses suffer repeat flash flooding. I'm not sure how ceramic tiles would bed onto lime ...

Good luck with it all.

Roger440
Posts: 32
Joined: Fri 7th Feb, 2014 1:48 pm

Re: River paid a visit. Lots to fix. Some questions!

Post by Roger440 » Wed 30th Dec, 2020 9:05 pm

YorkshireCottage wrote:
Wed 30th Dec, 2020 4:15 pm
It sounds like you have a combination of flooring which may complicate matters, particularly from an insurance perspective. They seem very keen to make house "waterproof" rather than breathable. If I was in your position, I would read this:

https://www.heritage-house.org/

and contact them for advice, as your insurers may not like the concept of potentially removing concrete to lay something breathable and, by definition, water permeable. You may need the help of experts to argue your case.

Sorry I can't offer advice on the type of flooring - stone flags seem to be the preferred option in my area where some houses suffer repeat flash flooding. I'm not sure how ceramic tiles would bed onto lime ...

Good luck with it all.
Im intending, once the plater and floor have been "stripped" to take a cash settlement from the insurance company and manage it myself from that point forward.

Im familiar with that website. Indeed, Peter surveyed my house prior to purchase.

The basis of my intention and hence questions is that i dont want to take up what is basically a servicable concrete slab (with services underneath). Just trying to figure out if the slab can stay but use breathable techniques above it. Next week will involve some phone calls, including to Peter.

88v8
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Joined: Wed 15th Jun, 2011 7:01 pm
Location: Glorious Gloucs

Re: River paid a visit. Lots to fix. Some questions!

Post by 88v8 » Sun 3rd Jan, 2021 10:08 am

Roger440 wrote:
Tue 29th Dec, 2020 7:50 pm
The front half, i already intended to remove the gypsum plaster (well ive already started prior to this) and some form of limecrete floor. (with a sump pump system of some sort)
I admire your positive attitude.

Gypsum off, yes.
Then my own dehumidifier would be top of my list.
Limecrete floor, hmmm.

The merit of limecrete is its ability to breathe away pervasive underlying damp. And not send damp into walls which have no dpc.
Unless you have this issue, which you may have in a cottage with no dpc, I think limecrete would be a solution looking for a problem.

Flooding, couple of days, drying out, this will not be helped by a limecrete floor. Indeed, because limecrete is more absorbent, arguably it could be detrimental.
So as an offset to flood residue, I wouldn't.

Skirtings... I would forget, if you have them. A quarry tile skirt, lime pointed, would do the job, if you use old black & red tiles it could look pretty good. Beyond the skirting, I would be leery of quarries as although they are 'period' they are also absorbent. I dislike ceramic tiles, but..... and the tile cement and grout must be waterproof.

Sump pump.... do you mean a pump in a hole? Perhaps a pump fed by a perimeter land drain?
There are two types of float. The enclosed type which can fit in a small space, or the tethered float which needs more room and a deeper hole.

The enclosed float type is very sensitive to dirt in the water. The float jams, it stops working. Not suitable for flood water.

What is needed is a dirty water pump, like this https://www.pumpsalesdirect.co.uk/clark ... -230v.html other brands and suppliers are available.

Give it its own power supply so if water gets into it and it trips out, it won't trip the whole house. Put it on an RCBO. Yes, they're supposed to be waterproof...

Depending on the water depth, it might be worth building one end of the floor higher, so if you're going to be away during winter you can move your furniture there, just in case.

Internal joinery, door frames, doors... there may be scope for making the bottom few inches unscrewable so it can dry out without warping.

Can you raise the external door thresholds, even a few inches. Yes it would make a step up, but..... I've seen this done on old coastal houses.

I presume there is nothing you can do in the way of making a bund around the house.

Here's to a better 2021.

Ivor

Roger440
Posts: 32
Joined: Fri 7th Feb, 2014 1:48 pm

Re: River paid a visit. Lots to fix. Some questions!

Post by Roger440 » Thu 7th Jan, 2021 10:19 pm

Thanks for the reply.

Fortunately, i already own 4 dessicant dehumidifiers at work. These were duly moved home ASAP!

Ref the limecrete floor, i have a conundrum

Yes, its a typical cottage of that age. Solid 9 inch walls. They were very damp when we moved in 5 years ago. The fireplace was bricked up, but the chimney not capped even though someone previius fitted a wood burner with no flue liner. So when it rained, it rained on the floor behind the bricks!. Add to that 3 hearts, original, then plastic, then another, then more plastic, with the internals wall of the fire place render in concrete. And the soil outside a foot higher than floor level. You can imagine what it was like. All sorted, well apart from plastering, currently bare brick. All nice and dry that end now (well until 23rd december!.

The remaining walls mostly still have gypsum plaster on. Theres no obvious damp, but stick a drill into one and its not completely dry either.

The floor looks to be 2 inches of concrete screed over mud!. Which has moved. A lot.

So, floor has to come up, flood or no flood. Given the walls are still a bit damp, im extremely wary of putting of slapping down a concrete slab and making things worse, or even no better. Ignoring floods, i cant see a downside to the limecrete floor with the foamed glass under.

As i alluded to, any floods are fast. In my fire place, having taken up the hearth, its been bare soil for a year or so. Mid flood, there was water circa 18 inches up the outside wall and the soil was still dusty dry! At no point did i see water coming in here. Im sure given time the water would have come up through the floor, but it was 3 hours. According to locals, this was the highest and longest lasting since at least 1968.

I hear what you say though. But i only have 2 options. Concrete, and in effect a "waterproof" slab, which, logically would be over some form of insulation either modern EPS or similar, but which in turn would need a sub base. So, sub base, insulation and concrete. Thats quite a depth of build up. Which means digging out whats there. Makes me nervous. Limecrete floor system can be as little as 220mm, as the sub base IS the insulation.

Im not sure there is a "right" answer. But given a short window of flooding, i cant imagine the limecrete absorbing that much water?

Part of the thinking was driven by the back rooms, which are concrete, then insulation, then screed.

Even with waterproof insulation installed, using a regular concrete screed means there will be water trapped between the insulation and both the concrete below and screed above. Using limecrete screed would allow this to dissipate over time. Yes, i could dig up the concrete floor and start again, but i really dont want to do that.

It is as i say, a conundrum. You cant succesfully stop the water coming in. Lime can dry out. Water trapped behind gypsum and concrete cant. It requires destructive work. I want to get to a point whereby, i can mop up afterwards, give it a good clean, and return to life as normal. I believe its possible. Indeed, the 2 oldest houses in the village which are rather more flood prone, but pretty much all original inside, thats exactly what they do. Furniture on blocks, wait till the water leaves, good mop and clean, return to normal.

You have made me re-think what im doing. Which is never a bad thing.

Which also leads to the pump. You can actually buy a specific system (cant find the link now) that has a drain around the inside of the room and the pump in a well. If water comes in, it simply pumps it out. Rather more efectively than my lashed up submersible that really needs a couple of inches of standing water to work. Generator is a given, though with the pumps, keeping the water at an inch or so meant we didnt lose power. But thats not to say we might lose incoming. I was, pleasantly, surprised how slowly the water came in. And most of that was through the patio doors which are hopeless, and the wall penetrations for the boiler, both of which can be fixed. Having had the dubious privilege of experincing it, im confident we can pump out faster than it can get in.

None of the doors or door frames have suffered at all. Like wise with skirtings. Though if i retain, id make them removable. The water just isnt here long enough or deep enough.

Realistically no way of raising anything far enough. Its still going to come in through the cracks, gaps and up around the sides of the floor. As i said, trying to prevent water ingress is futile. It just needs removing as fast as possible.

Need to talk to our limecrete freinds and see what absorption rate is....................

88v8
Posts: 2818
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Location: Glorious Gloucs

Re: River paid a visit. Lots to fix. Some questions!

Post by 88v8 » Sun 17th Jan, 2021 10:40 am

Roger440 wrote:
Thu 7th Jan, 2021 10:19 pm
Ref the limecrete floor, i have a conundrum....floor has to come up.........digging out whats there. Makes me nervous. Limecrete floor system can be as little as 220mm......limecrete screed would allow this to dissipate over time. ....I want to get to a point whereby, i can mop up afterwards, give it a good clean, and return to life as normal.
Mmm, yes.
Depth can be an issue. Foundations perhaps minimal. Undermining.
Necessary limecrete depth partly depends on room size, larger = deeper. Our 12x15' room, we went for 6" over 8" of LECA. (This was before foamed glass became 'the thing').
Even with that minimal excavation, the builder said that if Building Control were here, they would insist on underpinning, and I sad 'well they aren't so we won't'.
Nine years, OK so far.

As you say, perhaps there is no downside. Lime wets easier but dries easier.

In our cellar, flooded and mopped out Xmas eve, if you can call half an inch/20 gallons a flood, sandstone slabs over concrete, still damp.
Roger440 wrote:
Thu 7th Jan, 2021 10:19 pm
Which also leads to the pump. You can actually buy a specific system (cant find the link now) that has a drain around the inside of the room and the pump in a well. If water comes in, it simply pumps it out.
That's what we had installed in the cellar. We have two water sources there, the one that occasionally floods us as per Xmas, which we knew nothing about when we moved here, and the one that the pump deals with. That's land drains which terminate against our stone stairwell.
We had the stairs out for refacing, a duck lake developed down there. Arrrgh.

So now around the perimeter of the stairwell footprint we have a 3" land drain leading into a chamber with a pump. Only problem is that the pump has a float in a little plastic chamber, and periodically it jams. Like this https://www.permagard.co.uk/cellar-sump-pump-kit-platon from Permaseal who frankly should know better.

Our perforated drain is wrapped in two layers of Terram, so not much gets through. Only clay fines, like talcum powder, but it still gets in the float and jams it, not often, but all the same.... When it's been raining a day or so, that pump is shifting a regular 20 gallons down to 8 minute intervals.
No good having a dirty water pump if its float can be jammed by dirt!

What is needed is a pump with a float like this https://www.ebay.co.uk/itm/Clarke-Pvp11 ... Sw-itgAc4l that will never jam.

There are package systems with non-jam floats, this for example https://www.ebay.co.uk/itm/SPD-uk-SPD10 ... SwSYVf2M0J which might be a bit Mickey mouse or might be fine for very occasional use.

Me, I'd be more inclined towards one of the big name-package systems so you can sure of future support, just don't let them sell you the wrong type of float.

Ivor

Flyfisher
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Location: Norfolk, UK

Re: River paid a visit. Lots to fix. Some questions!

Post by Flyfisher » Sun 17th Jan, 2021 9:16 pm

Roger440 wrote:
Thu 7th Jan, 2021 10:19 pm
Which also leads to the pump. You can actually buy a specific system (cant find the link now) that has a drain around the inside of the room and the pump in a well. If water comes in, it simply pumps it out. Rather more efectively than my lashed up submersible that really needs a couple of inches of standing water to work. Generator is a given, though with the pumps, keeping the water at an inch or so meant we didnt lose power. But thats not to say we might lose incoming. I was, pleasantly, surprised how slowly the water came in. And most of that was through the patio doors which are hopeless, and the wall penetrations for the boiler, both of which can be fixed. Having had the dubious privilege of experincing it, im confident we can pump out faster than it can get in.
Woud it be feasible to implement a similar sort of system but external to the house? Not necessarily right up against the house so as to avoid any complications with foundations but a sort of 'dry moat' with a suitably sized pump on standby that could clear the moat as fast as water came into it.

I recently did some renovations on our ponds, which necessitated pumping them out completely. I hired a 6-inch diesel pump and was amazed at how much water it could move. It emptied a half-acre pond about 6 feet deep in only a few hours. Once empty, the pump could be set to tick over and it would keep the water level low even with water continually seeping in through springs and the nearby river. It was self-priming, electric start and simplicity itself to use.

Now that you've unfortunately experienced such a flood is it possible to calculate the rate at which water flowed would flow into an external 'moat'? A pump sized at, say, double that rate should then be more than capable. Admittedly it would involve some capital expenditure so might actually end up costing more than just paying for insurance, though it would of course avoid all the upheaval involved with flood damage.

Digging the 'moat' shouldn't be too expensive either. In the course of our pond works I discovered that a 16-ton excavator only costs around £500 per week to hire. OK, not exactly peanuts, but the amount of work it could do in a week was simply astonishing!

Anyway, just a thought.

Roger440
Posts: 32
Joined: Fri 7th Feb, 2014 1:48 pm

Re: River paid a visit. Lots to fix. Some questions!

Post by Roger440 » Sun 17th Jan, 2021 10:46 pm

Flyfisher wrote:
Sun 17th Jan, 2021 9:16 pm
Roger440 wrote:
Thu 7th Jan, 2021 10:19 pm
Which also leads to the pump. You can actually buy a specific system (cant find the link now) that has a drain around the inside of the room and the pump in a well. If water comes in, it simply pumps it out. Rather more efectively than my lashed up submersible that really needs a couple of inches of standing water to work. Generator is a given, though with the pumps, keeping the water at an inch or so meant we didnt lose power. But thats not to say we might lose incoming. I was, pleasantly, surprised how slowly the water came in. And most of that was through the patio doors which are hopeless, and the wall penetrations for the boiler, both of which can be fixed. Having had the dubious privilege of experincing it, im confident we can pump out faster than it can get in.
Woud it be feasible to implement a similar sort of system but external to the house? Not necessarily right up against the house so as to avoid any complications with foundations but a sort of 'dry moat' with a suitably sized pump on standby that could clear the moat as fast as water came into it.

I recently did some renovations on our ponds, which necessitated pumping them out completely. I hired a 6-inch diesel pump and was amazed at how much water it could move. It emptied a half-acre pond about 6 feet deep in only a few hours. Once empty, the pump could be set to tick over and it would keep the water level low even with water continually seeping in through springs and the nearby river. It was self-priming, electric start and simplicity itself to use.

Now that you've unfortunately experienced such a flood is it possible to calculate the rate at which water flowed would flow into an external 'moat'? A pump sized at, say, double that rate should then be more than capable. Admittedly it would involve some capital expenditure so might actually end up costing more than just paying for insurance, though it would of course avoid all the upheaval involved with flood damage.

Digging the 'moat' shouldn't be too expensive either. In the course of our pond works I discovered that a 16-ton excavator only costs around £500 per week to hire. OK, not exactly peanuts, but the amount of work it could do in a week was simply astonishing!

Anyway, just a thought.
Sadly, the front of the house directly fronts the road. So sadly, this isnt an option.

That said, at the back, it was a foot or more up the patio doors, so and moat would be overwhelmed in moments. The speed of the flood was, frankly, amazing. Though not unexpected.

So an internal pump is really my only option. Cant find the link to the system right now :(

Roger440
Posts: 32
Joined: Fri 7th Feb, 2014 1:48 pm

Re: River paid a visit. Lots to fix. Some questions!

Post by Roger440 » Sun 17th Jan, 2021 10:50 pm

88v8 wrote:
Sun 17th Jan, 2021 10:40 am
Roger440 wrote:
Thu 7th Jan, 2021 10:19 pm
Ref the limecrete floor, i have a conundrum....floor has to come up.........digging out whats there. Makes me nervous. Limecrete floor system can be as little as 220mm......limecrete screed would allow this to dissipate over time. ....I want to get to a point whereby, i can mop up afterwards, give it a good clean, and return to life as normal.
Mmm, yes.
Depth can be an issue. Foundations perhaps minimal. Undermining.
Necessary limecrete depth partly depends on room size, larger = deeper. Our 12x15' room, we went for 6" over 8" of LECA. (This was before foamed glass became 'the thing').
Even with that minimal excavation, the builder said that if Building Control were here, they would insist on underpinning, and I sad 'well they aren't so we won't'.
Nine years, OK so far.

As you say, perhaps there is no downside. Lime wets easier but dries easier.

In our cellar, flooded and mopped out Xmas eve, if you can call half an inch/20 gallons a flood, sandstone slabs over concrete, still damp.
Roger440 wrote:
Thu 7th Jan, 2021 10:19 pm
Which also leads to the pump. You can actually buy a specific system (cant find the link now) that has a drain around the inside of the room and the pump in a well. If water comes in, it simply pumps it out.
That's what we had installed in the cellar. We have two water sources there, the one that occasionally floods us as per Xmas, which we knew nothing about when we moved here, and the one that the pump deals with. That's land drains which terminate against our stone stairwell.
We had the stairs out for refacing, a duck lake developed down there. Arrrgh.

So now around the perimeter of the stairwell footprint we have a 3" land drain leading into a chamber with a pump. Only problem is that the pump has a float in a little plastic chamber, and periodically it jams. Like this https://www.permagard.co.uk/cellar-sump-pump-kit-platon from Permaseal who frankly should know better.

Our perforated drain is wrapped in two layers of Terram, so not much gets through. Only clay fines, like talcum powder, but it still gets in the float and jams it, not often, but all the same.... When it's been raining a day or so, that pump is shifting a regular 20 gallons down to 8 minute intervals.
No good having a dirty water pump if its float can be jammed by dirt!

What is needed is a pump with a float like this https://www.ebay.co.uk/itm/Clarke-Pvp11 ... Sw-itgAc4l that will never jam.

There are package systems with non-jam floats, this for example https://www.ebay.co.uk/itm/SPD-uk-SPD10 ... SwSYVf2M0J which might be a bit Mickey mouse or might be fine for very occasional use.

Me, I'd be more inclined towards one of the big name-package systems so you can sure of future support, just don't let them sell you the wrong type of float.

Ivor
I cant find the ,link to the one i was considering (laptop died :( )

But hear what you are saying re float switches. All good info.

As it turns out, the new part of the house ISNT screed over insulation over concrete. Its actually screed over concrete, and one assumes / hopes, over insulation. The test holes i created show the screed and concrete to be completey dry. So looks like i can stick to conventiol tiling in the new part, and keep the limcrete just for the old part.

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