Using a router on construction board (e.g. “Wedi”) to make a beveled corner

punkskunk , 11 months ago

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ciferecaNinjo OP , 11 months ago (edited 11 months ago)

Thanks for the feedback.

While you could cut a V and bend the board, I would not trust it to be waterproof and you would need to seal it with the sealant anyway

I think this is where the different kinds of boards differ. Some tests¹ demonstrate Wedi is not waterproof but Schluter KERDI and another brand is. This guy says KERDI board can be scored and snapped to fit into a car, and unfolded at installation and it maintains its waterproof properties.

If I opt for foam board then it would probably be Wedi so indeed it would theoretically need a waterproofing system on top. I say theoretically because I don’t think the shower is waterproof to begin with (it’s apparently tile directly on concrete rendered over brick). But I should still probably practice doing it right.

it would probably be stronger to just do a butt joint with sealant.

I’ve noticed construction board is fastened using a big washer of sorts and a screw through it. If the board is 10—15mm thick and I use those washers on a corner, they would overhang. I suppose I could cut the overhung portions off with an angle grinder. I’m also unclear on how strong the joint is if a screw is driven just into the foam to fasten the butt joint. Wouldn’t the screw pull out without much force? Perhaps I’ll use a 2×3cm piece of wood on the inside corner and screw both boards to that since I have that wood on hand.

Or when you say “with sealant”, do you mean no screws and sealant alone?

1. not sure I linked the right video.. I can’t access videos right now to verify.