Author Topic: Brick wall - plastic sheeting under foundation  (Read 1916 times)

stacheonfire

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Brick wall - plastic sheeting under foundation
« on: April 24, 2016, 05:36:48 PM »
I was digging out a garden bed that abuts the brick wall of our house. About half a foot down, I came across some plastic sheeting that extended out from under the foundation and into the garden bed.

I wanted to remove it, as it prevents water from draining from the garden bed, but I guess it's there for a reason. What is it there for - something to do with waterproofing of the house?


Miss Piggy

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Re: Brick wall - plastic sheeting under foundation
« Reply #1 on: April 24, 2016, 08:00:30 PM »
My assumption is it's preventing leakage into your basement. My elderly neighbors were advised to use plastic sheeting like that rather than spending thousands on a more permanent solution to their occasional leaking.

stacheonfire

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Re: Brick wall - plastic sheeting under foundation
« Reply #2 on: April 24, 2016, 08:52:44 PM »
thanks MP - I forgot to mention that it's a single storey house :)

lthenderson

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Re: Brick wall - plastic sheeting under foundation
« Reply #3 on: April 25, 2016, 08:50:53 AM »
For a single story house with no basement and no perimeter drain, it is probably just the water barrier put down before they poured the slab and can be cut back to the edge of the slab. They probably just left it long and then backfilled over it instead of taking the time to trim it back. If you have a perimeter drain, it may be acting as a filter fabric (not plastic) to prevent the gravel around your drain pipe from getting clogged with dirt. You definitely don't want to remove it if it is this situation.

Frugal Lizard

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Re: Brick wall - plastic sheeting under foundation
« Reply #4 on: April 25, 2016, 09:57:54 AM »
I have seen it used in the application noted by others and also to discourage termites when there is horizontal rigid insulation below to reduce frost penetration.  I wouldn't remove it.
I would move the plants further away from the house where there is more moisture.

Fishindude

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Re: Brick wall - plastic sheeting under foundation
« Reply #5 on: April 25, 2016, 02:05:42 PM »
My guess is that is was placed over the bare soil prior to putting in the garden bed on top of it, to prevent weeds from coming up in this area.
Most use a perforated weed barrier now for this purpose which stops the weeds, but still lets a little drainage through.

stacheonfire

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Re: Brick wall - plastic sheeting under foundation
« Reply #6 on: April 26, 2016, 05:32:35 AM »
Thanks to everyone for their response, I really appreciate it. I'm thinking that it's the water barrier for the slab that has been covered rather than trimmed back. There is no perimeter drain and no rigid insulation. There is weed matting adjacent to where the plastic sheeting stops, which is a different material (the weed mat is porous).

Thanks again :)