Small retaining wall and membrane?

[mrpeter]

I am in the process of building a 600mm retaing wall using concrete blocks from Bradstone. the blocks are 450x150x150. i have left drainage holes at the bottom and propose to partly back fill with pea gravel and then soil at the top Is it necessary or not to put a waterproof membrane between the wall and gravel/soil infill? If so what is recommended? The area behind the wall will be patio. Many thanks.

[The Builder]

Mrpeter, after the last couple of cold winters, similar walls have suffered a lot of frost damage.
I would never have bothered with a membrane before, but, now I would incorporate one. It would greatly reduce the amount of free water soaking into the stone.
Masonry releases water as soon as it becomes wet, even while it's still raining, but the least that can get in and freeze, the better.
As they say ............. "it can't hurt"

[mrpeter]

The Builder Many thanks for swift reply would ordinary heavy duty blue plastic dpc for under floors do the job? I have a large part of a roll left over from another job.

[The Builder]

Yes, ideal :o)

[AlBags]

Double-thickness if you can.
Use SS mesh flat against wall on top of DPM at drain outlets.