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Water under the floor


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#1 Guest_Den Butler (Unregist_*

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Posted 22 August 2004 - 10:10 PM

Hi, We have damp interior and exterior walls, we think this could be the problem of a high water table as there is pools of water under the floorboards in every downstairs room. Who would i contact to get a professional opinion as i don't think an every day builder will be able to give me the information i need. Also if the solution was to install a concrete floor, how much am i looking at?

Thanks

#2 Guest_horshater (Unregiste_*

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Posted 23 August 2004 - 10:25 AM

Check the water table by digging a trial hole outside and seeing where the water level comes to, in this weather you could easily have a water table which is only 6 inches below the surface, or even above..It's called a flood then!!! However, a high water table wouldn't explain damp walls, as the function of the DPC is to stop damp coming up the walls, which it should do unless the water table is above the DPC... see above (flood)

You should get rid of all water below the floorboards though, and this should be done by putting in a DPM and laying concrete on top of the DPM underneath the floor boards. You don't say how large a vertical space you have underneath your boards?. is it > 3 ft?

#3 Guest_Den Butler (Unregist_*

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Posted 23 August 2004 - 12:44 PM

Thanks, the vertical distance under the floor is about 1ft. The whole house has had a DPC installed prior to us moving in, but the walls are still damp. So i'm still confused about why it is happening, the house is quite old (1930's) however i don't think this is the main cause. Thanks for the advice though, is there a type of tradesman who could investigate further?

#4 cobra

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Posted 23 August 2004 - 08:22 PM

Hi might be you have a land drain that is damaged, you say work has been done maybe it got damaged or if it is an old house maybe it has just collapsed, not dagerous but might explain the water

#5 Guest_horsehater (Unregist_*

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Posted 24 August 2004 - 09:02 AM

You say that you had a DPC installed before you moved in, I guesss you mean a magic fluid one? These, in my opinion are highly unlikely to work with standing water less than a foot below your floors. The other problem may be that the plaster wasn't taken off the walls and replastered with the correct stuff after the new DPC was put in. You really need to dig a trial hole to see what the water table level is, that would also help identify a bust land drain if the water table is lower outside in a trial hole. Is it possible to construct a drain/ditch around the house to lead the water away from the building? You would need to get a architect who is up on damp problems and doesn't have a vested interest in any one solution. (Pun there)

#6 Guest_Den Butler (Unregist_*

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Posted 24 August 2004 - 06:57 PM

Hi, Thank you both for your advice, we didn't have a dpc installed, the previous owners did, i'm not quite sure what a magic fluid one actually is, all i know is that there are little plasic rivet type things in the walls going all round the house about a foot and a half from the floor, and we have seen the plans from the dpc company of what walls they treated. I am going to dig a ditch at the rear of the house to see the were the water table is, so thank you for that, then i think i will contact a chartered surveyor to check out the foundations just in case.

#7 Guest_horsehater (Unregist_*

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Posted 25 August 2004 - 08:18 AM

Hi Den, yep, that is the magic fluid one. i.e. a liquid is injected into the wall, which deposits a waterproof chemical into the pores of the masonry, through holes which are now covered by your little brown caps. I am being sarcastic when I say 'magic' The problem with the fluid injection system is that it is tested and approved under ideal situations, and unfortunately, in practice things are far from ideal. This leads to poor performance and dissapointment, as to replicate ideal situations and comply with the relevant British Standard is so time consuming, no-one could make a profit in what is an extremely competitive area. It is also not as affective as a plastic membrane DPC and expecting it to work when the wall is sitting in water a foot or so below is straining credulity. If there is a guarantee with the DPC system, and often the guarantee seems to be 'lost', don't get too bogged down in claiming from it. To check the water table a couple of holes a foot or so across is all that is needed. No need to go to the effort of digging a ditch at this stage.

#8 crookieguy

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Posted 13 March 2006 - 10:57 PM

I too have water under my home. We lifted the floorboards from beneath the dining room at the back of the house and there is about three inches of water running beneath. The floorboards are wet underneath. The floorboards are also wet underneath in the living room at the front of the house but there is no water. There is, however, damp on the interior wall in this room. I'm a first time buyer. I have no clue about houses but does anyone have a layman's explanation for this problem? Is it usual, expensive to fix and who would I contact?? Please help!

#9 saddened1

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Posted 14 March 2006 - 09:46 PM

dig a hole in the garden outside and check that that fills with water to the same level as the water under the floor. This will tell you whether it is a high water table in your area, or whether her is some under floor problem, like a leaky pipe. If it is a high water table, search the threads for this problem, which has already been covered ad nauseum.

#10 patrickd

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Posted 16 March 2006 - 05:00 PM

Den

If you have a 1930's house then you have a bituminous felt dpc already installed within it and the necessity for the injection one was, at least, questionable.

Your problem is most likely being caused by high relative humdity beneath the floor. You'll probably have at least one and possibly two courses of brickwork above the original dpc but beneath the level of the floor, thus within an area of high rh (probably 80% plus).

This time of year you probably have condensation occurring on the brickwork and this will manifest itself as 'rising damp'. The high water table isn't going to be helping amd you may have to address this to cure things.

Have a look at the article on my website www.pdoyle.net/wet_feet.html. It's something I come across on a regular basis. If you need further help, post back here or on the forum on the website

HTH

Patrick

#11 caliwag

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Posted 16 March 2006 - 10:25 PM

Damn good site Patrick, hope more people follow up your thoughts!
Good luck to you.
Wag

#12 patrickd

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Posted 17 March 2006 - 07:07 PM

Ah shucks, you're making me blush now :-)

Patrick

#13 frankie

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Posted 29 June 2007 - 03:31 PM

On the brink of purchasing a 1930's bungalow, present owners had new joists and floorboards and big new airbricks fitted some six years ago. Valuation surveyor recommended specialist contractor to investigate cause of apparent damp walls and inspect sub floor. My own investigations into the void revealed no concrete oversite, and soil damp enough to retain shape when squeezed into a fist. I spoke to the builder who did the work and he told me that whilst he was doing it, he was paddling in 2" of water. There was evidence of water on the walls.

Local building control officer says he has seen no evidence of high water table when inspecting the footings for recent extensions in the area.

Should I back away from buying this bungalow? It is in every other respect exactly what I want.

#14 Guest_cwatters_*

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Posted 30 June 2007 - 09:19 AM

A spring perhaps? Is the house near higher ground/on a slope?

It sounds like the previous owner has tried and failed to cure the damp problem. I think if there is still a damp problem you'd want to budget a lot in case a more radical fix is required. Perhaps taking up floors etc.

How high is the DPC above ground level? Is there enough height that you could add a layer of sand/concrete/membrane without having to excavate a lot? Perhaps get a builder to quote to do that then make an offer that much lower and some for the hastle factor/accomadation while work done etc.

#15 frankie

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Posted 02 July 2007 - 02:02 PM

Thanks for responding Cwatters,I imagine if there was a spring, there would be water there all the time? The house is on highish ground which begins to slope slightly in two directions. I am no longer worried about obvious traces of damp on walls near windows as I think this is probably condensation from poor ventilation and inadequate heating. What was of concern was the presence of damp and/or water sloshing about where I can't see it and the possible consequences. I am much comforted by Patrick Doyle's advice (see Patrickd post no. 7 above) and his response to my query on his own website forum.

#16 Guest_cwatters_*

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Posted 02 July 2007 - 06:47 PM

Yes if the floors aren't showing signs of being effected by damp then any on the walls is probably from another cause.

When I said spring I meant in the wider sense.. Our garden slopes slightly and there is a small "spring" in the front garden that comes and goes when it's wet. It caused by the trench dug for a water main acting as a French Drain. Surface water runs down the slope in the gravel surrounding the pipe and emerges where the trench was filled with soil further down.

It's not hard to create the a similar situation under a house. Our house has several foundation walls that run across the slope. I was concerned that water might collect on the uphill side of each wall/foundation. The soil is clay so water tends to hang around in puddles. To be sure I had our builder put in french drains to run any water off to the side and away.

#17 mitsu

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Posted 19 July 2007 - 07:53 AM

I have found 2 inch of standing water under my floor bards. I have no idea how long it has been there. I live half way down a hill and my block paved drive slopes towards the house. I live in a clay area.I am not sure if this is just due to the wet weather we have been having
I am not sure if i should contact my insurers. Can someone please advise me what to do. Should i try to pump it out or will it go itself, will i end up with dry rot??

#18 Guest_cwatters_*

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Posted 19 July 2007 - 05:50 PM

Don't panic.

Does the house have a Damp Proof Course (DPC)? Check where the water level is in relation to that. If it's above the level of the DPC then something should be done reasonable soon. If not then check the following and wait to see what happens..

Check that any paving is below the level of the DPC. Nothing should bridge it - no soil or paving up against outside walls above the level of the DPC. If the paving slopes towards the house there really should be a surface water drain along that edge something like this connected to the surface water drainage system..

http://www.hunterplastics.co.uk/underground/surfacedrainage/default.html

The void under the house should normally be ventilated. Typically there will be some air bricks in the outside wall. These should be above ground level to stop water flowing in via the air brick. Check they are clear/unblocked.

#19 mitsu

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Posted 21 July 2007 - 10:33 AM

the house was built in the early 60s, i cant see a dpc, maybe because the house was repointed 2 years ago. the water is about 12 inch below the bottom of the airbrick and the block paving is 1 course below the airbrick, the airbricks are the bigger ones, the size of 2 house bricks.

#20 lawley

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Posted 04 May 2008 - 01:27 PM

i`ve recently pumped 2" of water from under my floorboards,i believe the reason is the water table, the problem now is the smell of stagnent water. does anyone know if this smell will go and can i do anything to get rid of it.