Hi all,
Just wondering what length of drywall screws people would recommend using for 12.5mm boards for a ceiling. I've got some to put up at the weekend and I've got a huge box of 3.5 x 25mm screws and I would rather use them than buying more (I know they are cheap - it would just save me a journey :)
Thanks, Richard
You might get away with those for a wall board, but for a ceiling you really want about 1" of screw in the joists. A box of 8 x 1.5" should do you nicely. Make sure you've the torque control on your drill set to something suitable - plasterboard is not especially strong and if you drive the screw deep into the plaster, the edge will crumble away very easily. Screws only need to be just below the paper surface.
-- "Caution: Contents under pressure"
No. Too short.
For 12.5mm boards, the recommendation is normally 38mm screws assuming that you are going into timber.
Have a look at this:
download the datasheet on wallboards.
Which is another reason for getting the proper screws. These have a sharp edge at the outer edge of the head and cut through the paper neatly when driving the screw rather than crushing both the plaster and the paper over a wider area.
But the screw doesn't go through the paper?!
The point is that the screws have piercing points to make nice holes to get the screw started and the bugle head is designed to reduce the amount of material that has to be displaced/crushed to get the head below the surface. If you break the paper with the head you've gone too far. The pull-out strength comes from retaining the integrity of the paper layer, if you go through into the gypsum the whole thing's much weaker and liable to move.
I'm surprised at you Andy, I would generally have expected you to know better!
Fash
Especially having read that book on drywalling he's been plugging ;)
I recommend you get proper plasterboard screws and drillbit from screwfix. the drillbit has a "hat" on it, so it stops turning the screw when its in far enough. The screws are VERY VERY sharp.
Rick
Rick
Yes, you're quite right. My mistake - I was thinking about the points and they are not only for piercing the paper but also avoiding the need for drilling, which considering the number of screws required is a Good Thing.
I normally do. This was just a test to make sure that you were paying attention.
How many copies would sir like to buy?
So it sounds as though using more screws would not be suitable? Especailly since it IS a ceiling! Also I guess 12.5 mm gypsum board is pretty heavy? Interesting info, thanks.
The paper that you must not break through has marks on it that show you where to put the screw. Obviously if you cut the board or have different distances for the supports then you need to use different placings but the distances apart will be the same.
That tin s**te that the government is not going to set up a committee to stop the use of in the near future will probably be the stuff that the screws you have will be intended for.
.. >On Jun 22, 1:50 pm, Richard Conway wrote: .. >> Hi all, .. >>
.. >> Just wondering what length of drywall screws people would recommend .. >> using for 12.5mm boards for a ceiling. I've got some to put up at the .. >> weekend and I've got a huge box of 3.5 x 25mm screws and I would rather .. >> use them than buying more (I know they are cheap - it would just save me .. >> a journey :) .. >
.. >You might get away with those for a wall board, but for a ceiling you .. >really want about 1" of screw in the joists. A box of 8 x 1.5" should .. >do you nicely. Make sure you've the torque control on your drill set .. >to something suitable - plasterboard is not especially strong and if .. >you drive the screw deep into the plaster, the edge will crumble away .. >very easily. Screws only need to be just below the paper surface.
I recently painted a few rooms where a lot of the plasterboard fixings which had been skimmed over .... let the plaster crack on the fixings and in some cases the plaster dropped off sed fixings.
Why ?
Mike P
I've seen this happen where nails are used and not driven far enough. The skmimming plaster cracks and comes away.
If you place one drywall screw every 400mm or so then it will hold fine.
40mm screws would be ideal, but if the joists are reasonably solid then you can probably use your 30mm ones. The correct shrouded screwdriver bit is vital - it lets you whizz them in fast and know you will always get tee required seating of the screw. Note that unlike many screw driving tasks, you can stick your drill on a relatively fast speed since the screws are fine and easy to drive but also have a fine pitch that takes quite a few turns to drive home. 23kg / sheetIf you are doing a ceiling on your own then make a "dead man" to help. The is a couple of lengths of 2x1" The short one can be 2' long. The long one wants to be about the height of the room plus an inch. Screw the short one onto the end of the long one to make a big "T". You can now use this to hold your plasterboard in place for you while you fix it. Offer the board to the ceiling and hold in place with one hand. Then spring the dead man in underneath, it then keeps it held against the ceiling while you fix it. Once you have one or two screws in place they will usually take the full weight of the board if they are near the balance point.
A bit short for half inch pb but yeah they would work, _IF_ theyre PB screws.
If theyre ordinary non-pb screws forget it, you'd regret it. Standard pozi screws will ruck up the PB around the screw hole, making more to cover at skim stage, and making that skim sit on weak broken up pb. Also non-pb screws will rust slightly when anything wet is applied, staining the pb or possibly popping lots ofholes in the skim. Dont do it.
NT
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