Basement wall membrane

[RustyF]

I have had this issue where the builders plastic, which has been used as part of the waterproof membrane, is coming away from the wall.

The surface had been compacted there, and shrunk leaving a gap between the fill and the plastic.

As I have no eaves, the water was running behind the plastic and presumably onto the slab. There is a noticeable damp in the cavity of the basement.

To add to the issue, the plumbing had come off at the bottom of the downpipe, also where the plastic was away from the wall, flooding the entire area with water.

I have confirmed there is a perimeter drain with Ag pipe and gravel at the bottom.

What is the best way to repair this section of plastic? I was thinking some new plastic and byute tape it to the wall, but I'm really not sure.

 

  

[JacobZ]

Hi @RustyF,

A warm welcome to the Bunnings Workshop community and thank you for your question.

As I'm sure you are aware, the builder's plastic is there to create a physical barrier between the soil and the concrete to prevent water from soaking into or rising through the slab. It seems very likely that water getting behind this plastic is the cause of the water ingress issue.

My advice is to clean out any dirt from behind the plastic and glue it to the wall as flat as you can with Selleys Liquid Nails Exterior. I would then use the same Liquid Nails to stick corflute over the black plastic along the full length of the wall. It should extend down to the bottom of the trench with the top sitting slightly higher than the builder's plastic.

You can then use CAgroup Weatherproof Byute Flash Flashing Tape to seal any joins between pieces of corflute and seal the top edge of the corflute to the wall.

You should then backfill and compact the trench to ensure everything is locked in place.

Let me know what you think. 

Jacob