Plaster popped after timbers shrunk - when to get it re-skimmed?

[TyneFilth]

Hi all, I'm after advice on a plastering snag from my recent renovation/extension. We had the timbers put in in the winter and they've taken up a lot of moisture (they were covered, but moisture in the air and from screeding). They were plastered and all looked great, our builder said we'd be fine to go ahead and decorate but as the timbers have dried out there are a lot of shrinkage cracks and popped nail heads.

Our builder will do a re-skim as standard aftercare, but I want to plan for it to be done at the right time. Should we wait a year after it was originally done (his advice) although that'll be in the spring just after another likely damp season. Or should we push it to later next year? I think some shrinkage is still happening so I definitely don't want to do it this autumn.

The disadvantage with next year is that I worry that he'll say costs have gone up and expect us to pay some extra for the work. Should I try to get the commitment to re-skim for free in writing, as a quote valid for that planned date? Hoping for someone knowledgeable to have good ideas like @pigletjohn, hope it's ok to 'page' you!

Couple of the most noticeable bits around our roof lanterns.

Sorry but i cant see anything in those photos?

I'm no expert on popped nails. Was this boarded and skimmed to cover an old ceiling, or is it new plaster board on new timbers?

I think I have only seen it where the joists above were moving, for example a poor-quality loft conversion where the loft floor was not strong enough and flexed when walked on.

if it is round the roof lanterns it might be that the timbers were cut to form the opening, and insufficiently reinforced. You sometimes find this round loft hatches.

Have a look at the BR plans to see what size and spacing of timbers was designed, and try to remember if that's what was fitted. You can measure ceiling depth at the velux.

I don't see why drying-out shrinkage would cause nail popping.

if it is just a few I'd probably just use easiplast to fill them, not a ceiling reskim. But if the ceiling is moving I would first use screws (not nails) to improve the fix of boards to timber, anywhere it seemed loose when tapped.

hammers or guns to drive nails tend to shake ceilings and may encourage further cracking.

"Wait a year" might mean "leave it till you've forgotten, and I've got away."

Yes @bilbodog sorry it's pretty difficult to get a good shot when it's bright outside!

It's most visible in the entirely new part, so not cut to form an opening. I am confident the builder has done everything to the spec set in BR/our plans. No worries on that front. And he's also reputable and I don't think he's not going to come back. Lots of other examples of him doing elements thoroughly and explaining why.

I might prefer that our decorator do the filling when she comes to finish the painting. She's done that in a few places where there have been slightly proud fixings.

It’s a common problem on sloping ceilings for plater to pop/ crack around plasterboard screw heads. It’s like you say if the timbers had a high moisture content when installed, once the heat of the sun starts to dry them out in summer ,then you find will crack.

You don’t need the whole ceiling reskiming, just fill the holes with either easifill or the gyproc stuff they use to fill plasterboard joints on dry lining ( can’t remember the name ). Get a screwdriver and screw the screws in a bit deeper before you fill over them, it will make the hole a bit deeper and give the filler better adhesion.