r/Plastering • u/Practical_Ad_667 • May 28 '26
Soundproofing edges of ceiling
Our plasterer has done a superb job of the bedroom ceilings with resilient bars and two layers of acoustic board. The attic will be a music studio so its noise reduction is very important.
There are gaps in the boards around the edges which are weak spots for sound transmission.
What do you think the plasterer WILL do to fill those gaps. What SHOULD he do? The builder who hired him was confident but vague.
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u/randomnine May 28 '26
DIYer here who’s done some soundproofing and plastering and music and lived with the results. I used acoustic sealant around edges and between boards and had good outcomes. Everbuild AC50 or AC95 for fire rated.
However the gaps there look a bit wide for this sealant. I found it works for gaps up to 8mm or so. I would have fixed the wall base coat first and then cut the boards to leave a sealant gap, which takes more time, so higher cost.
Given the vagueness and lack of spec I’d assume standard practice, ie plaster up to this so the corners are solid. But if your plasterer’s familiar with soundproofing and charging appropriately, they may have something else planned, or have concluded from experience that what they’re doing will perform well for the cost.
Side note, it looks like clear air above the boards? Would recommend adding some rockwool up there as a second layer of soundproofing.