Water under subfloor - best solution?

Foul and surface water, private drains and public sewers, land drains and soakaways, filter drains and any other ways of getting rid of water.
Findizle
Posts: 11
Joined: Thu Oct 26, 2017 8:27 pm
Location: St. Helens

Post: # 114863Post Findizle

Hi,

My first post on here.

Moved into new house a few months ago, ground floor is suspended floor with crawl space and concrete foundation. I have found that along the back half of the house there is a water on the subfloor (varies up to 1 inch in depth).

I have had the drains CCTV'd and no issues there except a small crack in the soil pipe connection just below ground level which doesn't actually leak anything when toilet is flushed. Level varies so doubt it is mains water. The walls are also wet which leads me to think it is a combination of ground water and surface run off. The soil is very dense/ wet clay. The patio was running towards the house and you can see the driveway from my garage also slopes towards the house.

I am trying to figure out what the best solution is. My thoughts were.

1) Put a channel drain across drive at bottom of slope from garage.

2) Dig out soil along the back of the house and just around the gulley near drive and possibly waterproof paint the wall? I was then considering re-filling with appropriately sized gravel/ membrane. Possibly also perforated pipe and connecting to drainage to act as land/ french drain.

3) Re-lay patio so water is directed towards garden.

Have attached a few pictures of the current situation. You will see I've pulled a few of the flags up and excavated small areas to investigate.

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Any help and advice would be most appreciated!

Thanks,

Dan

digerjones
Posts: 889
Joined: Fri Jan 18, 2008 9:32 pm
Location: cheshire

Post: # 114864Post digerjones

What problem is the water causing in the subject floor
dylan

Findizle
Posts: 11
Joined: Thu Oct 26, 2017 8:27 pm
Location: St. Helens

Post: # 114865Post Findizle

Hi,

No problem as such other than a length of wood (looks like it was retrofitted possibly to help prevent problems with a wobbling washing machine). But surely having water under the house isn't good?

Couple of pics below, ignore the dye that was poured onto the surrounding ground to check for water ingress (you can see lots of it).

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Thanks,

digerjones
Posts: 889
Joined: Fri Jan 18, 2008 9:32 pm
Location: cheshire

Post: # 114866Post digerjones

Like you've already suggested, stop all water getting near the house make sure all drains gullies etc are working correctly
dylan

seanandruby
Site Admin
Posts: 4713
Joined: Mon Jun 26, 2006 11:01 am
Location: eastbourne

Post: # 114867Post seanandruby

Could be groundwater seeping in. You can tank it, waterproof frim inside...expensive.
sean

Findizle
Posts: 11
Joined: Thu Oct 26, 2017 8:27 pm
Location: St. Helens

Post: # 114876Post Findizle

Hi,

I think it might be groundwater too, I am going to dig up the patio and re-lay it so it drains away from the house. Would digging out the clay soil along the back of it and replacing with gravel help matters?

I have excavated around the drain, any idea how I could go about connecting up a channel drain to this. Likely I will replace the old clay gulley so I can get the downspouts and kitchen waste pipes under the grids.

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The channel drain would be running literally infront of the gullet across the driveway. Unsure if I can tap into the plastic gulley from the channel drain or if I need to fit a mini inspection chamber?

Cheers,

Dan

seanandruby
Site Admin
Posts: 4713
Joined: Mon Jun 26, 2006 11:01 am
Location: eastbourne

Post: # 114883Post seanandruby

Cut out side of the gully the size if your aco.
Placing shingle against house wall will encourage water to head that way. As you say reverse slabs, or install aco. Look at tanking it also.
sean

jwill
Posts: 148
Joined: Mon Feb 08, 2016 6:00 pm
Location: leic

Post: # 114901Post jwill

If you pump away the water does it come straight back or only after prolonged/heavy rains?

Was thinking if you have a deep enough invert level you could simply drain the water from dumbfloor?

jwill
Posts: 148
Joined: Mon Feb 08, 2016 6:00 pm
Location: leic

Post: # 114902Post jwill

*subfloor

seanandruby
Site Admin
Posts: 4713
Joined: Mon Jun 26, 2006 11:01 am
Location: eastbourne

Post: # 114903Post seanandruby

jwill wrote:If you pump away the water does it come straight back or only after prolonged/heavy rains?

Was thinking if you have a deep enough invert level you could simply drain the water from dumbfloor?
To where? Groundwater will keep on coming. Usually tanking from outside, or sealing from inside will remedy it. A fall to a sump then pumped can control it, depends what Dan ontends to use it for and if viable options. As stated it can become expensive
sean

jwill
Posts: 148
Joined: Mon Feb 08, 2016 6:00 pm
Location: leic

Post: # 114912Post jwill

If you had a low point under subfloor where you could run some perf pipe could this not be connected into a storm water drain if invert level allowed? Not to stop the water coming but just to drain it when it does come.

Findizle
Posts: 11
Joined: Thu Oct 26, 2017 8:27 pm
Location: St. Helens

Post: # 114921Post Findizle

Hi all,

Thanks for the replies. Update is I have had the clay pipe P trap and gulley replaced with plastic and they have fed a channel drain into this. Also had cracked rest bend fixed on soil pipe. Slightly annoyed they didn't install the second aco for the rest of the drive, suppose I can always add that in though.

Now, where my downspout and 2x kitchen wastes empty to the gulley I need to sort out how they enter here as some spill behind the back (hence the bit of plastic gutter). Now I noticed that they have fitted it lengthways along the wall whereas a lot of pictures on the internet showed it at 90 degrees to this, is there a correct way? If I rotated it could I use the 2 boss inlets on the sides for the 2 kitchen 40mm waste feeds or is it meant for a gutter downspout? Quite hard to find out what they are meant to be used for.

As you can see water still gathering here, next steps will be to re-pave and then get the patio running the opposite way, too wet for that today though!

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Thanks,

Dan

digerjones
Posts: 889
Joined: Fri Jan 18, 2008 9:32 pm
Location: cheshire

Post: # 114922Post digerjones

Looks ok to me. Just extend the waste and rain water pipes into gully. You can cut holes in the gully top
dylan

lutonlagerlout
Site Admin
Posts: 15182
Joined: Fri Aug 04, 2006 12:20 am
Location: bedfordshire

Post: # 114924Post lutonlagerlout

personally i wouldnt do this as it is not a roddable gully
rather the leaves and crap sit on the grate than go straight down into the system
cheers LLL :)
"what,you want paying today??"

YOUR TEXT GOES HERE

seanandruby
Site Admin
Posts: 4713
Joined: Mon Jun 26, 2006 11:01 am
Location: eastbourne

Post: # 114927Post seanandruby

Soil pipe = trapped gully.
sean

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