sand and cement render in bathroom

M4RTYB · Post by **M4RTYB** » Tue Dec 28, 2021 12:41 pm

Hi guys,

As with most jobs get stuck in and things change.
Its a 1930s house and I’m working on bathroom.
Its tiled around the bath, the rest is painted plaster with its fair share of cracks and hollow sounding plaster. Plan was to remove the lot,dot and dab boards up then tile floor to ceiling all four walls.
What I’ve found is the top half of the wall the plaster/render literally just fell off, and crumbled away back to brick/block. The bottom half looks to of had a new layer of sand and cement and it is solid, there’s literally a line from old to new and the cracks where all in the old section.
Now I can’t decide what’s the best option , Should I just sand and cement the top half to blend in with the lower? Or try to get it off and board the lot? I’ve added a couple of pictures to see the different layers that I’m working with, some sections are really thick 15/18mm other under 10mm.
Any help/ideas much appreciated!
Thanks

dewaltdisney · Post by **dewaltdisney** » Tue Dec 28, 2021 2:31 pm

This is how houses were built up to the '60s, the walls would all have a cement scratch coat with plaster over. Because of the varying thicknesses, you have to make up I would suggest a cement-based scratch coat to get it to a level just under the existing plaster, some would use bonding, and then skim it all over with a finish coat. You could of course batten out and drywall it, or even dot and dab which will all shrink the room slightly.

You can choose whichever way you feel more confident with.

DWD

M4RTYB · Post by **M4RTYB** » Tue Dec 28, 2021 7:01 pm

Dewaltdisney thanks for your reply, so ok to use thistle bond coat to build out the thickness and butt up to the older but solid stuff , then I take it a skim of plaster before tiling? Having read that I can’t tile direct to a bond coat?
Pva before bond coat?

Or a cement scratch coat, would that need a finish on top for tiling?

Thanks!

M4RTYB · Post by **M4RTYB** » Tue Dec 28, 2021 7:31 pm

Dewaltdisney, searching through the forum it appears you did a similar job but using a sand cement mix 3:1?

dewaltdisney · Post by **dewaltdisney** » Tue Dec 28, 2021 7:32 pm

Yes, both would need diluted pva sealer to stop the wall sucking the water out of the spread. A thick bonding coat needs a good day plus to dry out.

DWD

dewaltdisney · Post by **dewaltdisney** » Tue Dec 28, 2021 8:11 pm

On reflection bonding might be the best way to do this as a scratch coat might be tricky for you to get right. Just give it time to dry before applying a finish coat.

DWD