Plasterboarding question

[snadge]

We are going to board the ceiling later today and i have a few questions

1. Is it necessary for all 4 edges of the board to meet on joist/noggins?
(we are going to run them in opposite direction to joists but full lengths dont end/meet on a joist, to install a noggin would mean fitting in 2 others to fix it too or should I cut the board to fit?)

2. Is it necessary to use filler in joins?
(Ive laboured for a few plasterers in past and ive never seen them fill the joins, they just put scrim tape over them then plastered it)


thanks

 

[ajrobb]

Is it necessary for all 4 edges of the board to meet on joist/noggins?

It depends on the joist spacing and board thickness. I think a single layer of 12.5mm board doesn't need noggins up to 450mm and 15mm board can go up to 600mm. I think the perimeter should be supported with noggins within 50mm of the wall.

 

[snadge]

Is it necessary for all 4 edges of the board to meet on joist/noggins?

It depends on the joist spacing and board thickness. I think a single layer of 12.5mm board doesn't need noggins up to 450mm and 15mm board can go up to 600mm. I think the perimeter should be supported with noggins within 50mm of the wall.

I just got 9mm for the ceiling so maybe I will cut them or use a bridge plate which I read about elsewhere

thanks

 

[ajrobb]

I just got 9mm for the ceiling so maybe I will cut them or use a bridge plate which I read about elsewhere

http://www.british-gypsum.com/pdf/SB07_Timber joist_02.pdf

 

[^woody^]

9mm boards are only really suitable for 450mm joist spacing, and in any case wont give you the required fire protection or sound insulation to the ceiling. They should be 12.5mm boards

If the edges are not jointed on noggins or joists, then they will bow and the joints crack

You only need to fill the joints is using paper tape and joint filler. You can use self adhesive mesh scrim tape instead

 

[Richard C]

Boards should be 12.5mm as woody suggests. Regards the need for noggins on the cross boards or perimeter, this depends on board thickness (9.5mm is not good), joist spacing & weather or not your just taping & filling the joints or skimming the whole ceiling afterwards. You can find all the detail in the link ajrobb posted.

Providing you close butt the boards you don’t need to fill before taping but I always rough fill the screw heads & apply an initial tight skim of plaster over each tape forcing it well into the mesh as I apply the 1st skim coat to the ceiling.

 

[snadge]

430mm spacing on ceiling joists - we took 9mm down from ceiling too

will 430mm be OK for 9mm? weve got the boards now

 

[Richard C]

9.5mm may be what was up there before but even British Gypsum now specify 12.5mm for ceilings with up to 450mm joist spacing without noggins or 15mm up to 600mm joist spacing. Virtually no one uses 9.5mm for single layer boards over ceilings these days but if you’ve bought the boards