Can you plaster out a small sag?

[tombodge]

Ive got an old house and ive replaced all the lath and plaster with 12mm plaster board.

One room the ceiling was sagging really badly so I replaced all the joists

The landing area didnt look bad so ive plasterboarded it but it turns out it is sagging in the middle. Its only 1.6 meters wide and with a strate edge on it theres about 3/4 of a inch each side which would need building up. (The lowest part of the sag in the center is 3/4 lower than the edges)


I can add a timber in the loft to stop it moving any more and with the help of a acro improve on it alittle bit but is it possible to skim this sag out? With bonding and a state edge?


Im really not in the mood to pull all my plasterboard down and replace all the joist's.

Thanks for any advise

 

[stef99]

you don't need to replace all the joists. But i'm not sure how they were installed un-evenly in the first place?

One way to remedy it is to pull the plasterboard down and pack the underside of the joist with thin strips of wood.

if the joists are not level properly, does that mean you used un-regulated joists? that's never a good idea. for the obvious reasons.

however, 3/4 inch of plaster is not going to happen unless the plasterer is prepared to mess around with it (for which he will charge you).

a skim usually is never thicker than 2-3mm. that should give you an idea f how flat it needs to be.

 

[tombodge]

Hi. Thanks for the reply. The joists that ive put up are fine. Its the 100 year old 2x3 that are all over the place. I guess over time they have sagged. For some reason i never thought off packing them down . Ill do that cheers