Hi, simple plasterboard question with luck:
What fixing plasterboard on wall studs and ceiling joists, is it OK to screw the plasterboard on, cover the joints with scrim tape, and skim, or, is it better to fill all the board joints with bonding plaster before taping and skimming?
Yes that is ok
cover the joints with scrim tape, and skim,
Yes that is correct
No the adhesive Scrim we use now, will not adhere to a damp surface.
If you were using the old cotton Or jute scrim that was the way we did it
Kind regards Edward
Good, that saves a job ;-)
================================================================/ Just mention: On TV recently saw use of a fibreglass mesh tape that is slightly sticky and is applied to the joint BEFORE any plastering mud is used. With other tapes AFIK usually some mud is applied to the joint and the, typically perforated paper, tape is stuck to that initial application and 'smoothed' into it with the trowel. Further applications of mud (plaster), as many as two or three more, finish the joint. Metal is best for 'outside' plaster corners. Terry.
The stuff I have is fiberglass mesh, slightly tacky on one side.
I believe the mesh tape you saw is the scrimtape used almost exclusively in the modern building trade for years now.
Glen
Yup thats the stuff! :)
Also...for anyone who is interested....you can buy it in extra wide rolls for covering larger gaps/joins between boards. Can save alot of fannying around.
Glen
Also the screws to be used are the black ones. Look for the words gyproc on the box if they are zinc coated. They are not supposed to break the paper, just press heavily into it. That means take care to set them square on.
You only need the tape on the joints not the other columns and rows of screws.
The boards are usually marked with the correct spacings for them. Use the white face of the sheet.
The ones I have are a black pasivated finish (Screwfix IIRC), bugal head etc. Using one of the shrouded "dry walling" bits seems to work quite well at setting the depth.
Must admit I had not seen any markings on the boards I have (1/2" Knauf) I will go have a closer look. I have been fixing on 400mm centres (i.e. joist / stud spacing), and using three or four screws across the width of the board. Doing the ceilings first - I might reduce the screw count a bit for the walls.
Is adhesive scrim as good, though? With jute scrim, the plaster coats it & the board face - with stick-on scrim the plaster can only go on one face, and doesn't fill gaps.... eh?
J.B.
The gaps are big compared with the material -- the plaster goes right through it. The stuff is only slightly tacky anyway -- just to hold it in place until you cake it in plaster. The sticky doesn't and isn't meant to form any part of the strength of the finished plasterwork.
But the plaster only pushes up to the board, I shouldn't think adheres so well.
Yes, I have actually used it somewhat.
No, of course not. Having used both for a couple of houses, I think that:
Jute does a better job, but takes longer to apply. Self-adhesive scrim is far quicker and looks neater, but is only a "one sided" fix, and not as good.
That said, the most important things for avoiding cracking are suitable framework and fixing.
J.B.
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