How to make a sump for underground water.

[RichD1]

Whilst replacing joists and flooring in our hallway I've discovered that corner of the house has lying water in the underfloor void. This is probably why the flooring has gone and that we suffer from condensation in the winter.

I've started clearing the oversite which is like mud but as I take the level done, water runs from under the stair well which is at the front of the house. The water is clear and not smelly and as we haven't had any significant rain for the last four or five weeks I'm feeling that is must be an underground water course.

Interestingly the lounge void is next to the stairwell void at the front of the house and is dry. This confirms my suspicions that the watercourse runs under the corner of the house.

My thoughts are to dig a hole outside on that corner of the house to see what is going on. If I find running water how can I make a lined sump so that I can divert the water away from the house. I would then fit a sump pump to take the water away. The sump would be fed by a french drain running along the front of the house.

Your thoughts on this would be welcomed as would alternative methods to solve my problem.

Richard

PS: I've checked the mains water supply and we have no leak.

 

[JohnD]

Have you got a water meter?

 

[RichD1]

Yes, that's how I checked for a leak.

Richard

 

[jacko555]

Before building a sump, get the water tested to see if its tap water. Doesn't mean there isn't a leak elsewhere

 

[RichD1]

Before building a sump, get the water tested to see if its tap water. Doesn't mean there isn't a leak elsewhere

At the moment it is like a mud bath down there as the oversite in the void corner has broken up whilst trying to clear it exposing the underlying clay soil. This hasn't help with the water collecting there.

 

[^woody^]

Your flooring has gone and you suffer condensation because of inadequate ventilation/circulation to the floor void. Timber floors are ok with standing water, which it's no different to just having damp oversite concrete in terms of humidity.

 

[jacko555]

At the moment it is like a mud bath down there as the oversite in the void corner has broken up whilst trying to clear it exposing the underlying clay soil. This hasn't help with the water collecting there

The water is clear and not smelly and as we haven't had any significant rain for the last four or five weeks I'm feeling that is must be an underground water course

Maybe a gypsy well?

Maybe it's condensation like woody says. Maybe a river. Maybe a leaking water main / drain.

Before going to the effort of digging a sump and drainage system I'd want to be sure of the source.

Watched a grand designs years ago. They found what they thought was a underground stream. Spent tens of thousands adding pile foundations. Turned out to be a leaking water main on the next road.

 

[RichD1]

I did think about this and it looks like there have been more air bricks fitted over the years. I'm going to fit a couple more around the corner walls where the water is lying.

Someone suggested fitting an underfloor fan to push or pull the humidity out. Is this a possible solution?

Richard

 

[RichD1]

The area I live in is called Radipole Spa. Apparently up till the 1950's there were two laundry's about half a mile away serving the main town and they had large underground tanks to collect water.

 

[mattylad]

I live in Spring Terrace, we had a leak/flood once and we were being told we had a spring running under us.

Turned out to be a local land drain was filling up and flowing through its wall then into our terrace because it was blocked at the bottom.

Investigate well.

 

[RichD1]

Decided I will add a couple of more air bricks above where the standing water is and also rough plied bricks in the water to create a bigger surface area to allow the water to evaporate quicker. Will then investigate the underground water when I’ve got more time.

Richard

 

[oldbutnotdead]

As above, make sure underfloor is well ventilated. Sump- if you want to, get yourself a submersible pump (machine mart, Toolstation, Amazon all flog them), dig an hole deep enough and wide enough to take the pump & make sure there's enough room for the float switch to work properly, give it power, pipe the output to your drain & off you go. If the hole starts filling itself in, line it with a few beer crates or a gabion cage or something like

 

[RonnieE]

Before building a sump, get the water tested to see if its tap water. Doesn't mean there isn't a leak elsewhere

I'd agree with this, a salts analysis test will tell you if you are dealing with water with chlorides (from the tap or waste), nitrates (from water rising through the ground) or neither (usually rainwater)