DIY Doctor UK DIY Forums

Hi everyone:
We have a dado moulding around our bathroom walls. I bungled when redecorating recently because (I now realise) I used an unsuitable decorator’s caulk to fill the gap between the dado and wall before painting. The caulk absorbed condensation, causing the paint on the dado to fail, so I’m going to have to take the old caulk out and re-paint the dado. Stupid mistake - Live and learn.

My question is this: What should I do to complete this job properly? My idea was to remove caulk, reprime and paint, then after painting go round the dado with waterproof silicone sealant - but I’m not sure how neat that would look so I’d be interested if anybody has other/better suggestions.
Thanks!

Hi jamoo1980,
Unless the dado rail was dry and was painted all round you are likely to get the paint lifting off due to the damp in the bathroom. Silicone sealant cannot be overpainted so always looks out of place when used to seal between a wall and timber detail.
Prepare the rail, seal to the wall with decorators caulk and allow it to dry for a week or so, then paint. The alternative would be to fit upvc dado rails.
Regards S

Hi Stoneyboy
Thanks for your reply. Yes I was worried about silicone looking out of place. Can you recommend a decorators caulk that is suitable for this purpose? I'm asking because I did seal it with decorators caulk before, and that turned out to be a big problem: even though I'd over-painted it, the caulk still absorbed moisture from condensation running down the wall, making the paint on the dado lift off, and I had to go round and cut it all the caulk out. I'm reluctant to re-caulk and have the same thing happen again!

When you say painted all round - are you asking if the dado was painted all over including the back before attaching to the wall? This was not a new dado installed by me, so I don't know the answer to that, but it had definitely been painted several times by previous owners of the house. I didn't take it back to bare wood - that would have taken ages - but I did sand it and reprime it. I'd be kind of surprised if any moisture was getting round the back of it.
Thanks again for your help!

Hi jamoo1980,
Unfortunately wood in a bathroom will always be expanding and contracting with moisture levels even if it has been painted. You could try using an acrylic frame sealant which would allow you to fill and wipe clean, silicone would be useless because it would spread as you finished it off. You could try using silicone but form a bevel all along the top of the dado, you’d have to do this in one pass with no tooling to finish it off. It’s not easy!
Regards S

Thanks - I’ll give acrylic frame sealant a go if problems seem to be persisting. Appreciate your advice - thanks again!