Water Under House

[rsbhj]

Hi

Not sure if this is the right section under Building.

I had a problem when I moved into my property where the main drain was blocked and water was underneath a section of the house.

The drains were unblocked and the water then retracted. The drains were checked by camera and no collapse or damage, the guy said with it being old clay the water would have seeped out and thats what cause it to rise under the floor.

When I pumped the water out I could see the area it will fill up from the ground below. Once drain was cleared it stopped.

No issues for over 6 months since yesterday with some real heavy down pour of rain, there has been water under the same section, its gone this morning, and suspect it was only there for a very short period yesterday, it was the smell I noticed this morning, checked under floor and its damp ground but no standing water.

Where do I start in getting this looked into as I cant have water coming up under the house even if this is just 2-3 times a year when there is a heavy heavy down pour. The rain was torrential and as I said has been fine for last 6 months.

Thanks and any advice on this is very welcomed.

 

[KenGMac]

rsbhj, good evening.

One possibility is to make an insurance Claim on your home Insurance under the heading of damage to underground services? but next year your premium WILL rise, that is when you shop around.

Most glaringly obvious possibility is that your old clay drain has blocked up again. Do you know what caused the blockage last time? was it roots, and if so was the drain "Lined" with a modern material.

Do you have a single [so called] Combined drainage system where rain water and waste water use the same U/Ground drain?

Does the drain that was "cleared" serve any other properties? if so it could be considered a Sewer that is repaired by the local Water board.

Ken

 

[rsbhj]

Hi

We made a claim last time as there was lots of standing water and drains needed cleared. The blockage was due to wipes. Drains were checked with camera all all ok, even watched the footage myself.

The pipe is definitely not blocked this time as all the rain water cleared fairly quick once the rain stopped, along with what ever came under the house must of cleared quickly.

I believe it is a single pipe combined pipe. The pipe only serves my property, meets out in the main street the rest.

The amount of rain that fell was huge, its clearly been too much water for the pipe and system to handle but the fact that it came into the house again is something I need to sort, might only happen once or twice a year, as last 6 months its been dry even with steady rain over the winter and spring, but the amount on Sunday was sever which caused a lot of standing surface water for about 45 mins then cleared in about 30 mins.

 

[Harry Bloomfield]

The amount of rain that fell was huge, its clearly been too much water for the pipe and system to handle but the fact that it came into the house again is something I need to sort, might only happen once or twice a year, as last 6 months its been dry even with steady rain over the winter and spring, but the amount on Sunday was sever which caused a lot of standing surface water for about 45 mins then cleared in about 30 mins.

My own guess, is that you are correct - it's a lack of capacity in the pipe leading from your houses. I doubt the authorities will be able to do much about it, perhaps you could dig a sump and add a sump pump for those occasions when it does flood?

 

[rsbhj]

so could that be in the driveway to sit between the drain pipe and the house? See rough sketch, dashline is drain pipe with 2 manholes and small drive way drain, the 2 circles are sump possible locations as it is only that side of the house that is effected and only really the front half of that side if house (basically hall and under stair area).

The plan is to extend out the side but prob 4-5 years off doing that.

Whats the sump do just take the excess water into a well type container, where does that water pump to tho?

Or does the sump sit under the area of the house that is effected?

The water seems to come under the foundations and rises just under where the stair cupboard is and then spreads out

 

[rsbhj]

Would digging a trench along the side of house back filling with gravel and a land drain pipe be a solution? The issue would be where to empty that land drain pipe.

The water must be far enough down and spreads under the house where it finds a path to rise under the hallway

 

[Harry Bloomfield]

Would digging a trench along the side of house back filling with gravel and a land drain pipe be a solution? The issue would be where to empty that land drain pipe.

The water must be far enough down and spreads under the house where it finds a path to rise under the hallway

Or a rapidly rising water table?

 

[rsbhj]

Or a rapidly rising water table?

Water table is high in the area, but the fact it only comes under one section of the house means there must be a weak area? see attached red area is where it covers X is where I suspect it rises.

The issue is when the pipe was blocked and when there was a mass down pour. During normal conditions and days of rain its fine even with a high water table. Its when the pipe is full that the occurs.

 

[wessex101]

A camera survey alone is not enough to establish whether the drains are leaking. Did they do a pressure test on the drain? If not it is a relatively simple job that should not cost much and well within the realms of DIY with reasonably cheap drain testing tools.

 

[rsbhj]

No a pressure test was not carried out but I think from the 2 examples that has performed it’s own 2 separate pressure tests firstly a blockage and secondly a mass surge of water into the system.

The water clearly comes in due to these situations, although the occurrence is rare and never been enough to caused damage it’s still managing to find a path into the house and rise in the same area.

I am not sure redoing a man made pressure test would tell me any different to what I know? However open to hear differently.

The issue is capacity and what’s best to increase or divert away from that side of house.

 

[wessex101]

But the drain should not leak even if it is blocked or flooded. The worst that should happen is appliances and gullies etc. should start to back up and overflow.

It sounds to me that the old clay drains are past it, probably all the collars and joints are leaking. So it doesn't matter what else you do if you do not replace the drain run you will always get leakage into the ground which will find it's way into the house.

 

[rsbhj]

Hi

yeah exactly, and I said the same to the guy who came out with the camera, why did the water not back up the pipes.

His take on it was that obviously water will take the easiest path and the out clay pipes will allow water to seep. He seemed to think the joints were ok but who knows.

so the fix is dig it up and replace the clay pipe, or increase capacity with another pipe either way going to be a fairly big job to dig up, how deep are these pipes normally? The manhole at driveway before the street is deep, maybe 5ft as an estimate.

it’s maybe one to wait until I extend out the side and try think of a temporary fix until then as will be a few years away?

 

[JohnD]

how old is the house?

IME clay gullies and bends are always cracked, broken or leaking in old houses

though somebody once told me thhere is an old house with no cracks, I have never seen it, and don't know where it is.

 

[rsbhj]

House is late 60s

the thing I am struggling with is it comes up in the same area under the floor, strange to me that even if there is a crack and then under pressure it forces it’s way to the same bit.

the camera survey definitely never highlighted any major defects.

would a temporary soloution be a land drain down that side of the house, our with the pipe being further down any leaks would bypass that?

how far down are the pipes usually?

 

[KenGMac]

As johnD above gullies are notorious for leaking and cracking, they are generally not fully surveyed with the CCTV because the camera cant get around the bends, so easy to get at cracks go un noticed.

Given you have an old clay system for what ever reason a leak can occur especially when there are old cement joints in the collars

Question? does your main drainage line run near the area that tend to flood under the house?

As for depth of existing drains?? [obviously] from "0" at a gully to the depth at the nearest M/Hole, suggest you get an idea by lifting a M/Hole cover and measuring what you have.

As for the idea of a land drain? I would completely exhaust investigations of the existing drain first.

If you are installing a land drain, you need to [in effect] work back the level from the [proposed] land drain "outfall" which will probably be a manhole, the outfall can be at any reasonable level in the manhole [obviously] above the invert of the passing drain.The beauty of a field drain is that it only needs a very, very small drop in level to work.

Ken.