Timber Cladding to Block Retaining Wall

[gchloeg]

Hello, I'd like to install timber vertical slats and a cantilever bench to a 900mm high x 100mm thk solid block retaining wall. Our builder didn't apply a waterproof membrane to the earth-retaining side of the wall - I presume this is because it would undermine our neighbours fence post (to the far right of the image) and I'd really like to avoid removing the plants and lifting up pavers.

So, I'm looking for advice on how to best protect the timber from what is now a permanently wet wall. Should I install a waterproof membrane before the supporting battens? Will the brackets we plan to use for the bench supports be ok? (https://contemporaryfencing.com/product/seat-brackets-for-cedar-seating-bench-tops/)

Any hints/tips/advice much appreciated.

 

[freddiemercurystwin]

I would be inclined to fix some vertical 25x50W timber battens with some sloping horizontal 25x50 battens to those, then fit your cladding, fixing a breathable membrane between the masonry and the vertical battens. The gap behind the cladding should be open at the top and the bottom allowing air to circulate, in essence creating a vented cavity. Plenty of bumf on google etc and you might think it's only a retaining wall but the principles all still apply especially as your base wall may be wet. Think about how you'l detail ithe cladding aorund the seats that will have to protude through the cladding and the corner details.

Something like this:

BTW 100mm wide is pretty slender for a wall of that height especially with a load of seats/cladding hanging off it, a double or triple skin (at least at the base) wall would have been a much safer bet.