Rendering plywood

[Stan44]

Good morning all,

I need to reduce a door opening in an external, single skin block wall by around 8" and try to match into the existing external render without a join that is too obvious and unsightly.

The easiest way would seem to be 4' x 2" stud clad with 12 mm wbp plywood. I have some rendering mesh if that would help. The question is: can I render plywood?

Any suggestions or advice would be much appreciated.

 

[freddiemercurystwin]

You can, eventually it will rot but will take a good few years though. You can get all encompassing membranes but they're overkill for such a small area. There is also a fair chance you may get cracks around the opening as the expansion will be different for masonry and plywood. Ensure you hack off some render around the existing opening so you can fix your mesh to the ply and the surrounding masonry.

 

[Richard C]

Even if you can get it to stay on the ply/lath without cracking (the ply/stud & render will dry out at different rates), it will most likely crack the first time soemone slams the door.

You will stand a much better chance if you use a cement based backer board rather than ply as this is dimensionally stable when wet but I reckon it will still crack.

 

[^woody^]

You can stud and ply, but you will need to fit a breather membrane to the ply (or building paper), and take the mesh past the join (hack some existing render off), and not have straight joint.

 

[leew2]

why not just use blocks? buy enough blocks for the height of the opening, cut them to length then use a stainless steel tie in bracket to join it to the existing brickwork, then no problems with it rotting or cracking when the door slams.

 

[Stan44]

Many thanks everyone, much appreciated.