DPM with a retaining wall

29 Jul 2011
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United Kingdom
I'm building a small retaining wall, only 6 rows tall, double skin. I have already done first 5 rows so I am now at the point where damp-proofing should be done.

I have bought a membrane, 1200 gauge, for the external (earth) side of the wall, but I am bit puzzled with how to lay it - since earth will be up to top of the 5-th row only I thought I could start laying it from between two topmost rows (so it's squeezed underneath the topmost row), but I can't find any images or examples that it's the correct way. Does this make any sense?

Another thing is what to use as a protection board, between the membrane and earth? For example I found some sold by "RIW", but they seem to be specialised for industry, not DIY-ers, so I need something that is easier to get.

Any advice much will be much appreciated!
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Hi, thanks for replying!
That thread is quite useful, but still I am not sure about:
1. How to attach the membrane to the wall?
2. What kind of board would do? I think RIW is a bit over the top for this,but there's also 0a mention of a polystyrene board - which sounds ok, but I am not entirely convinced (I guess I just need a second opinion).
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Just use a bit of gaffer tape or similar to hold the dpm in place. Once the protection board/soil is against it it won't be moving anywhere. You can use polystyrene if you like it will work just fine, all you are doing is providing a barrier to prevent any sharp stones from penetrating the membrane, as mentioned in the other thread any decent merchant will sell alternatives to the RIW protection board.

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