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Installing small fence onto block wall with future proofing for lean-to?

Postby Spooon » Wed Dec 30, 2020 8:37 pm


Pretty much as the title says. I need to install a small fence on top of an existing block wall... Our dog has realised it can jump the wall and head straight over the road into the woods. The run is about 14m in total and the wall currently is 1.2m at its highest point. Will not need raising by more than another 1.2 at any point. I'd like to leave myself the option of installing a lean-to on a section of the wall/fence at a later date. The wall is sound and solid.

Can I fix 4x4 timbers straight into top of block (via concealed galvanised brackets, or U-shape) which are drilled/bolted/chem-fixed down and them build fence on that. Leaving the 4x4s longer in the area which I eventually want to build a covered walkway/lean-to.

Or, as I suspect, will this compromise wall structure and I'm going to have to attach posts along the side of the wall?? Can I at least notch the 4x4s so I dont have a full 4 inch of timber sticking out from the wall? Alternatively, should fix a timber horizontally along the length of the fence and essentially create 'stud-work frame for fence and lean-to?

Any help/advice/links to relevant hardware greatly appreciated... I've got pics to add to post once I've figured out how to resize :D

Cheers :)
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Simply Build It

Postby stoneyboy » Thu Dec 31, 2020 10:26 pm

Hi spooon
You don’t say how wide the existing wall is but assuming it’s 100mm you must fit posts up the side of the wall. Top fixing on any thickness of wall will not work. The posts can be 100x50mm and suggest you use trellis to minimise the risk of wind blowing the wall over.
Regards S
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