Fixing timber frame to a cavity block wall

adocholiday

Hi all,

There's an existing well pump house on my property that needs replacing. There's a 4-course cavity-block wall around the base and the original construction has 3x2 boards attached to the back of the cavity wall for framing, with cladding screwed onto the back of that. The blocks are wrapped in therma wrap and the water runs off the cladding onto that. The whole thing is a disaster and there's a pic below.

What I'm planning to do is tear down all of the existing timber and put some new proper framing on top of the cavity blocks so that the whole thing is water tight and can be insulated. What I'm not sure about is how to anchor the new framing to the cavity blocks. Given that the cavity faces upwards, there isn't very much block to anchor to so I'm not sure how to go about it. I could potentially lay a course of solid block on the top of the cavity blocks to give a solid base for the framing, but I'd prefer to not bother with that if I can avoid it. Any ideas or pointers would be much appreciated.

meercat

Keep the cavity blocks inside the new timber frame

adocholiday

https://www.boards.ie/discussion/comment/121039954#Comment_121039954

Unfortunately I can't, at least not without significant excavation. It's set into a small hill so the blocks are below ground level on 2 sides. The framing has to go behind or on top of the blocks

meercat

Fill the cavity with post mix and anchor into that when it sets so

TopCreator

https://www.boards.ie/discussion/comment/121041374#Comment_121041374

you can find some good deals at Chadwick's Ireland for post mix : https://www.chadwicks.ie/all-products/building/aggregates-paving/kpro-crete-post-10-34331.html

hesker

I’d be thinking you should raise your block height anyway to keep your woodwork clear from the ground

adocholiday

https://www.boards.ie/discussion/comment/121041374#Comment_121041374

Good call, I wasn't sure if I could fill the cavity but if that's a valid approach then I'm pretty happy to do that, after all it's just a well pump house.