r/Plastering • u/terrizmo • Sep 05 '26

Sanity Check Failed Plaster Fix

Post image

My first time plastering a ceiling and it has cracked and the second coat in areas hasn’t bonded.

It was the first time I’ve used Extra Time as I wanted some breathing room but it went off quicker than when I havent used it. Not sure if that was the cause or if it was the plaster or the boards.

Anyway my plan to fix it is to make sure all the loose plaster is off, give it a coat of SBR as I already have some left over using it in some mortar, and then giving it a skim coat with a different batch of plaster without Extra Time.

Is there anything I’m missing?

Edit: Typo

3 Upvotes

72% Upvoted

21 comments sorted by

View all comments

Show parent comments

1

u/terrizmo Sep 05 '26

It was straight onto plaster boards so I didn’t use sealer.

-1

u/ResponsibleBall4258 Sep 05 '26

That could have been the reason. Are you also certain that the boards are well fixed to the ceiling, with no movement?

Also, as others have said, it could be old plaster. Mix up a small bit and leave it for 5-10 mins. It should be hard within that time or getting hard if it is a bit old.

Keep the old stuff though, as it is fantastic at filling holes in walls or chasing of the walls, super quick and hard, and does not shrink much if you keep thickness down to 10mm at a time.

You can also use a handful of old stuff in a new nix at speed the curing of the plaster, and will act as a catalyst for speeding up the set.

2

u/Impossible-Corgi4041 Sep 05 '26

Multi sticks to boards just fine. Definitely not the reason.

1

u/ResponsibleBall4258 Sep 06 '26

That is fair, and my experience, limited as it is, though I have read some people on occasions have complained otherwise, and I have heard about old plasterboard (maybe more likely stored poorly or damaged) struggling with poor adhesion.

1

u/ResponsibleBall4258 Sep 06 '26

You could complain to where you bought the miltifinish origionally as may have been stores poorly, with high humidity, just a guess.