Water coming up through concrete slab

[reb78]

We have installed stables in the end of one of our barns. Most of the time it is fine but with heavy rainfall like recently, the water comes up through the joins in the slab. We are on a hillside and the ground behind the shed is higher (rapidly slopes up about 10ft from the rear of the shed to a flat field. So it appears that as water soaks into the ground, the pressure is forcing it up through the floor of the shed. Is there anything that is not massively drastic that could be done to stop this? The only solution I can really think of is to remove the stables, lay a membrane on the exisiting floor and then pour a thick slab on top of that in one piece but financially it doesnt make sense to alleviate the effect of a few days a year of wet, so I dont think thats going to happen.

The only other thought I had was whether it would make sense to deliberately make holes in the centre passageway that could be covered with a grill to actively let the water out where we allow it rather than inside the stables themselves the shed is 34' wide by 40' deep with stables all around the edges so dont know if drainage holes to let water UP in the centre passageway would alleviate the pressure pushing it up through the slab at the perimeter?

 

[addjunkie]

Dig a trench round the outside, line with weed membrane, lay in polly drain pipe, back fill with gravel, and give the excess water an exit route.

 

[Gritineye]

On the high side dig a trench across the back and down the sides to below the bottom of the slab, say 6' min. That will take the water pressure away, fill with hardcore membrane and cover over if you feel fit afterwards.

 

[reb78]

I did think about the trench idea but the shed is one of four linked together and its about 200ft in total. The ground behind slopes up quickly from the back of the shed so I would have to dig a channel to get a digger in as well as I cant do it by hand and then that leaves me with worries about bank retention after I have excavated the current bank back!!

 

[AVI_8]

The trench won’t have to be as large as you might think, around 18 x 18 inches, I can’t think of any other way to get the water to route around the buildings rather than under them, it’s easily do-able by spade even if it means just doing a bit at a time, if you paid a guy to do it I can’t think it would be more than a days work.

 

[Morrisman]

Our local 'bikers' cafe is like that. This year, for the first time ever, water is coming up through the join in the concrete floor where the main room was extended years ago. A lot of the surrounding ground has also flooded for the first time ever. I'm assuming the water table is high enough to force it through the slab.

We've also had major floods on the main road to my village, which has never happened in anybody's memory.

 

[gaz1]

a fench drain at rear of your stables with a drain dug underneath through yours then allowed into a drain or at low poimt allow to run free is only alternative

 

[DAPPH]

If it is seeping / running in at the damp course level or wall join to the floor slab ....disc cut& clean out a trench on the inside ...... adjacent to the wall , make it foot wide a 3 inch deep run off gully. You should be able to use a brush & shovel to keep the gully clear

 

[brightspark]

Dig a trench round the outside, line with weed membrane, lay in polly drain pipe, back fill with gravel, and give the excess water an exit route.

ive just done that for a customer yesterday and today. her garage was flooding tanked the floor and part way up the walls as well as land drain and gravel all round

 

[winchman]

Photos would be good, but basically have a look around and see why the water table is up, local stream blocked, grass now concreted etc
Then if all else fails a French drain type thing behind the wall should help, don't worry about the hill falling as you can dig out tank the wall, then back fill so the water has an easier path.
I do wonder if the drain would work at the top of the 10ft slope at the top of the field as this should remove much of the water before it hits the slope?

 

[GG1]

One of our sheds is on a slope and needs a french drain around the high side for the 2 or 3 times a year water comes in, but it's visible surface runoff.

No idea what the going is like under your slabs, but from what you describe it might effectively be the water table rising and finding its way up, which a french drain might not help. In which case your idea may be the way to go - an aco drain, set it in place and drill through both the drain and the slab in the appropriate area.

 

[addjunkie]

I did think about the trench idea but the shed is one of four linked together and its about 200ft in total. The ground behind slopes up quickly from the back of the shed so I would have to dig a channel to get a digger in as well as I cant do it by hand and then that leaves me with worries about bank retention after I have excavated the current bank back!!

While I appreciate the challenges, Id say do it once properly, not keep revisiting the issue. A decent digger man would make fairly light work of it. If your worried about bank slippage, set in galvanised I-girder with either proper railway sleeper wall or concrete panels.

Foot deep trench is probably enough!

All depends how steep it is really.

 

[500e]

Might cure if you cut a trench at the front to reduce back pressure, also have seen a horizontal drilling machine 100mm that they slid a pipe into the hole as soon as removing drill, I think it was steerable used for getting cables under roads etc.

 

[Bullet2012]

Nope, everyone is incorrect.
Tank the walls, add a heater, a pump and jets and an overflow through a wall at about 5 ft.
Market as an equine hot tub/ jacuzzi.
charge extortionate fees.
Sorted.

 

[voipio]

Trenching around the perimeter is the easiest way forward, but it doesn't need to be massive, unless the water inflow rate is huge. I just use a trenching shovel to dig a 3" wide trench, and that is plenty enough to get a surprising amount of water out of the way, and not flooding the sheds. One thing to ensure, is that the drainage channel has a slope for the water to run down, and that there is a drainage path to lead it away from the stables. There's no need for a digger, and the trench doesn't have to be deep. It's probably no more than an hours work to go round the 40ft by 34ft. As the drainage channel is being dug, there's a chance you may notice water springing up, which might give some clues as to where to best put your efforts.

If there's a low point in the stables where the water tends to gather, it might be worth considering cutting a square out of the concrete and digging a sump to put a submersible pump into.

 

[Gareth J]

A french drain, with perforated pipe at the bottom, with a bit of run on it, around the underground bits is really the best course of action. However, if that really isn't an option, you could try cutting a ~6" chanel through the concrete (along the join/s) digging out the concrete, going as deep as you can muster, and with a good run on it, putting in perf pipe. Backfill with clean gravel and reconcrete.

 

[reb78]

I'll do some pics. The rear of the shed is basically maybe a foot more of.the concrete slab and then earth banks very steeply up about 10ft. The earth here is about 1/2 inch topsoil and then stone. Digging a 200ft trench in that will be back breaking unfortunately. Theres no room to get a digger in unless you also dig room for the digger.

 

[reb78]

One of our sheds is on a slope and needs a french drain around the high side for the 2 or 3 times a year water comes in, but it's visible surface runoff.

No idea what the going is like under your slabs, but from what you describe it might effectively be the water table rising and finding its way up, which a french drain might not help. In which case your idea may be the way to go - an aco drain, set it in place and drill through both the drain and the slab in the appropriate area.

Water table could be right. We are on a pretty steep hill - 15% up from.our house and steeper down from it so roughly 1in 6 to 1 in 7. The shed slab is 10' below the field above but thats because the shed is cut back into the hill. In the part I have as a workshop, the PO has laid what looks like a new 4" slab on top of the old - I suspect for this reason.

 

[Screwdriver]

Might cure if you cut a trench at the front to reduce back pressure, also have seen a horizontal drilling machine 100mm that they slid a pipe into the hole as soon as removing drill, I think it was steerable used for getting cables under roads etc.

Exactly what I was thinking. Not the ideal solution but it wouldn't do any harm to improve drainage away from the buildings. Sounds like it would be much easier access too.

 

[reb78]

Might cure if you cut a trench at the front to reduce back pressure, also have seen a horizontal drilling machine 100mm that they slid a pipe into the hole as soon as removing drill, I think it was steerable used for getting cables under roads etc.

This is kinda where I was leaning - in my mind if I give the water an easy exit point that might alleviate pressure back under the slab so it isnt forced up and through the more difficult exit points?