Water ingress in crawl space

hdh74

We have a bungalow with a crawl space and clear evidence of water ingress, though not to flooding depth. It is however leaching lime from the mortar and salt from the bricks. There is evidence of pointing needing replacing but the walls are damp. So far the timbers remain dry and in good order.

I'd really like to get someone out to have a look and advise us on how the water is getting in - I've already had cameras down nearby pipework and ruled those out, and what if any remedial action we need to take.

I've tried damp companies who say ask a structural engineer, and structural engineers who say ask a damp company. Access is a little difficult, though both myself and my hubby have been down there - it's not a 'suited and booted walkaround. It may well be nobody wants the job - it seems whatever work we want doing lately, trademen are cherry-picking the easy payoffs.

I have thought about using a combination of pea shingle and damp membranes to line the base to reduce moisture levels then repointing the brickwork. Not sure if this would fix it, though.

Any advice welcome.

stuart45

How deep is the crawl space? It sounds like it's ground water from a high water table.

tacpot12

I'm inclined to think that a french drain around the foundations would be more certain to cure the problem. You might start by digging some test pits around the foundations to see if the problem is worse in a certain area. If the problem is quite localised, it might be a burst pipe or faulty sewer. If the problem is present in all areas, a high water table is the likely culprit and a french drain would be the solution IF you can can find a low point to drain the water away to. 

hdh74

stuart45 said:

How deep is the crawl space? It sounds like it's ground water from a high water table.

It could well be. The crawl space goes about three feet below ground level. Best solution - any idea please?

hdh74

tacpot12 said:

I'm inclined to think that a french drain around the foundations would be more certain to cure the problem. You might start by digging some test pits around the foundations to see if the problem is worse in a certain area. If the problem is quite localised, it might be a burst pipe or faulty sewer. If the problem is present in all areas, a high water table is the likely culprit and a french drain would be the solution IF you can can find a low point to drain the water away to. 

tacpot12 said:

I'm inclined to think that a french drain around the foundations would be more certain to cure the problem. You might start by digging some test pits around the foundations to see if the problem is worse in a certain area. If the problem is quite localised, it might be a burst pipe or faulty sewer. If the problem is present in all areas, a high water table is the likely culprit and a french drain would be the solution IF you can can find a low point to drain the water away to. 

A really awkward layout would make a french drain very challenging. The house is joined sideways onto outbuildings in one direction- right up to the boundary, and another house in the other, meaning there's no way of getting lateral drainage to a low point. There is also pipework across the front where I would lay part of the french drain, this then runs away at right-angles to a soakaway. This has all been checked and appears to be draining freely.

stuart45

The modern method for suspended timber floors is to have a concrete oversite that's at least 150mm below the bottom of the joists, but above the highest point of the external ground level, or if not it's laid to fall to a drainage system. 
Alternatively as tapcot12 suggested.
Or some people just leave it.

Eldi_Dos

Create a sump at where you perceive to be lowest point then instal a submersible pump with a float switch and run discharge line to a drain.
Get a competent electrician to do the electrics for you.

I always felt more at ease if it was a 110 V pump.