boards sagging

[stevethespreader]

if that was my ceiling i would take the boards down and put noggins in , its going to be a waste of time skimming that if you dont want cracks and joint lines

 

[bagofjuice]

I pushed up the sagging part and screwed in at ~5" spacing. The result is better but still sags 2.5mm on the one board I tried.

I was planning on having it skimmed. Will the skim not cover this kind of thing assuming I finish screwing all the boards with lots more screws? This is still being used as a garage so not looking for aesthetic perfection.

I'll take some more photos tomorrow with a proper camera.

 

[stevethespreader]

Will the skim not cover this kind of thing assuming I finish screwing all the boards with lots more screws? This is still being used as a garage so not looking for aesthetic perfection.

I'll take some more photos tomorrow with a proper camera.

of course skim will cover it but just be aware that you may have a crack at some point as in my opinion there is not enough screws holding the board up along the joint no matter how many screws you put along the joists it would have been better putting noggins in to pull the board up tight

 

[cajar]

Does nobody agree the problem is he's put screws between the boards instead of into them?

 

[roy c]

Does nobody agree the problem is he's put screws between the boards instead of into them?

Thats what I thought when I first read the post, but what he meant was he only put screws in @400mm on each joist so as "kingandy " said there would have only been 12 screws per board....

 

[cajar]

if you check the pics though it looks as if there is one screw between two boards. This would cause the boards to droop imo.

 

[kingandy2nd]

I pushed up the sagging part and screwed in at ~5" spacing. The result is better but still sags 2.5mm on the one board I tried.

I was planning on having it skimmed. Will the skim not cover this kind of thing assuming I finish screwing all the boards with lots more screws? This is still being used as a garage so not looking for aesthetic perfection.

I'll take some more photos tomorrow with a proper camera.

Pushing up the sags and extra screws won’t work my friend.

If you imagine it like this, you have plasterboards that are 1200mm wide when flat, however if you hold them in the air the length from one side to the other might be 1195mm (the board is still 1200mm but it’s sagging down a few mm making the distance from one side to the other slightly shorter).

Due to the way that you’ve screwed them in, i.e screwing in one side then the other you’ve incorporated the sag/bow of the plasterboard into the ceiling. If you try measuring the width of one of the spaces on your ceiling that your plasterboard has been fitted into, you’ll find it’s a bit shorter than 1200mm. Measure it by putting your tape measure onto the adjacent board at the edge, otherwise you’ll just measure across the board including the sagging bit.

As you’ve now fitted 1200mm PB into, say, a 1195mm the PB has to sag otherwise it won’t fit a no amount of extra screws will help as the additional PB has nowhere to go.

The only solution I’m afraid is to take down the PB and refit in the correct manner. As the other guys have suggested, it’s worth fitting some noggins at the same time. Try spacing the screws at 250mm instead. You can re-use the same PB, but don’t re-screw into the same holes.

I know it was probably a pain to get the PB up in the first place, and the last thing you want to do is to take it down, but better to get it right in the long run.

 

[joe-90]

I'm pretty sure that those boards will push up without binding. If they don't just run a Stanley knife down the joins - it'll get taped anyway.

 

[bagofjuice]

if you check the pics though it looks as if there is one screw between two boards. This would cause the boards to droop imo.

I've draw lines on the boards so I know the centres of each joist. I think you've mistaken that for two boards.

...but what he meant was he only put screws in @400mm on each joist so as "kingandy " said there would have only been 12 screws per board....

That should be 20 screws.

Due to the way that you’ve screwed them in, i.e screwing in one side then the other you’ve incorporated the sag/bow of the plasterboard into the ceiling.
...
The only solution I’m afraid is to take down the PB and refit in the correct manner. As the other guys have suggested, it’s worth fitting some noggins at the same time. Try spacing the screws at 250mm instead. You can re-use the same PB, but don’t re-screw into the same holes.

I spent a large part of yesterday adding more screws so now there's 50 screws per board.

Due to the cuts for staggering of boards and cutout for the loft hatch there is actually only 1 whole 2400x1200 board up there.

I think taking all the screws out and starting again is beyond me. If it was a room in the house then it would be a different story. I was thinking of perhaps adding noggins from above to the affected areas without taking the boards down.

 

[bagofjuice]

Some pics now it's finished.

 

[joe-90]

Nowt wrong wi that bro.