Running water in void under ground floor

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RichD1

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On fitting a new rad in the hall for my daughter I found that the floor joists had gone rotten so I started to replace but noticed that the floor of the void which was covered in mud was quite damp. The void is about 4' to 5' deep at that point which is considerably lower than the side driveway and the front of the house.

Today I've just been down there and cleared the 1" or so of rubble and mud which appears to be on a concreted oversite, back from the side wall for a foot or so to see what was going on and found that water was running in from the outside at the very bottom.

The area the house is located in is referred to as a 'Spa' so we've always been led to believe that there are underground springs somewhere. The ground is also solid clay from about 9" from the surface.

This water is causing a massive condensation problem in the house and the weather is not really cold yet.

I can see that there are not enough airbricks fitted but until the water can be stopped from getting into the void this appears futile at the moment.

Any ideas on how to cure running water getting into the underfloor void?

Some pics of the water puddle.
 
Sorry Guys, forgot to add the pic.
 

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The water is not ideal but with sufficient ventilation and damp proof course that's intact it shouldn't cause a problem directly.
The fundamental solution is to ensure the ground level outside is lower, but that ship may have sailed already. But do make sure any drains are not leaking and all paving slopes away from the house and is drained if it ends up too close.
Have you checked with the neighbours to find out if it really is a high water table?
The final solution would be to remove the floor timbers,replace the sleeper wall doc with modern plastic put hardcore, DPM and concrete to weigh it down in the floor void, and improve the ventilation.
Even that could be risky in case it builds up underneath and starts making the house walls damp.
 
Thanks for the response John.

Annoyingly the ground level slopes from the front to the back of the house and on the back half there is a single storey single brick walled outhouse type of arrangement which presumably was a coal hole etc. and this is solid concrete so prevents the water easily running away in that corner.

The outside ground level is about 2 to 3 bricks below the DPC level. But the majority of the inner walling below the DPC is dry it just appears to be running down the outer leaf until it hits the footing and then comes in.

The side driveway was paved several years ago by the previous owners so wondering if that might cause problems.

Also where that puddle was forming in the bottom of the void we've found that there was an outside drain which appears to be blocked! However, I don't think that is the main problem but certainly not helping.

I think one of the first things we ought to do is get someone in to clear the whole of the oversite of muck which will obviously hold a lot of water. Once that's done we might be able to see if there is a major problem or not.

Is there any solution to stop the humidity coming up through the flooring and into the house apart from increased underfloor ventilation? Could I install a couple of small extract fans to draw more moist air out? Is putting a vapour barrier down under the carpet underlay a solution?

Eventually we would want to insulate the ground floor if we're going to increase the air circulation, but what's the best method and could a vapour barrier be put across the bottom of the floor joists? Or will this cause more wood rot problems?

Richard
 
You may need a ground test to see if this is high water table or a spring. After having the supply and waste pipes checked for leaks.

A sump pump may be needed if the condensation can't be controlled via air bricks.
 
IF, you were to fit a dpc in the void, it would have to be done below any wood, or they would eventually rot. Better to do the checks first to find where the waters coming in, then decide on the course of action from there.
 
RichD1 said:
<Snipped> Annoyingly the ground level slopes from the front to the back of the house and on the back half there is a single storey single brick walled outhouse type of arrangement which presumably was a coal hole etc. and this is solid concrete so prevents the water easily running away in that corner.

The side driveway was paved several years ago by the previous owners so wondering if that might cause problems.

Also where that puddle was forming in the bottom of the void we've found that there was an outside drain which appears to be blocked! However, I don't think that is the main problem but certainly not helping.
Click to expand...

Any hardsurfaces outside that run back to the house walls without suitable drainage will aggrevate or maybe even cause your problem. Blocked drainage is a serious issue and needs to be resolved, that can include a CCTV of drains to make sure they are not broken and leaking elsewhere. Adding dyes to water in the drains can sometimes reveal if water elsewhere is coming from the drains, however unlikely to help if the leak is minor. Certainly check the void after heavy rainfall.
 
The lying water has almost gone today and the water when it was puddling was clear and not smelly which doesn't suggest a drainage blockage. There's no rain forecast for the next few days so will keep an eye on it to see what happens.

Thinking of digging a hole in the front garden by the bat window to see if we can get an idea on the water table. It might be that a french drain across the front wall and round and down the side might be the answer.

Just discovered that the house across the road had french drains put in across their back garden to divert water away from the foundations when they had a rear extension built. The ground level runs downhill from this property toward our property so am going to contact the Surveyor who worked on the project to find out what he discovered.

Thanks for all the advice guys.

Richard
 
RichD1 said:
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Just discovered that the house across the road had french drains put in across their back garden to divert water away from the foundations when they had a rear extension built. The ground level runs downhill from this property toward our property so am going to contact the Surveyor who worked on the project to find out what he discovered.

Richard
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My Father in Law had a similar problem that he only found when they had an extension built. He had at least 12” of Gin clear water under his floor. It didn’t affect any of his woodwork but it was some way up the brick piers that supported the downstairs floor. He had the water board out who took samples - it wasn’t mains water but he had houses across the road to him that were higher than his. His garden, which was about 300’ long, ran downhill away from his house so all he did in the end was break through the lowest point in his rear footings and insert a drain pipe into a soak-away and that cured his standing water problem. I don’t know whether he ended up with the mud that you have though. They lived there for at least 15 years after that with no other problems that I can recall.
 
Hi Motman,

That sounds exactly like our situation.

The back garden slopes quite a lot away from the house and the back steps down even in very dry conditions always has a slight weep of water. At the moment it is sodden.

Unfortunately that back corner is where the solid outhouse floor is or your suggestion would be worth looking at. Sometime next year they are thinking about an extension but I don't think those footings will be touched. Perhaps our Surveyor who is going to do the drawings might be able to help.

Richard
 
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