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  1.  
    Hi,

    I know it's short notice, but Iam due to start plasterboarding the ceilings tomorrow, just checking if what we are planning sounds ok.

    Decided to use 15mm thick plasterboards as the manufacturers/Building Control say that you don't need noggins for 600mm spaced joists. The room is approx 3m x 8m

    Most internet advise says to lay the long side perpendicular to the direction of my metal web joists. Just want to be sure I stagger them correctly.

    I plan to lay boards end on end across all the joists at one edge of the house (8m edge), cut the last board to size and then start the next row with a full board and head back towards the original side of the house, introducing a stagger between rows. (all outer edges of the room have supporting battens to fix to already)

    Then start the whole thing again for the next rows. So it will look a bit like a starndard brick wall layout, although the stagger will probably not be 50%.

    I do however worry about the absence of noggins between the joists along the long edges of the boards. Plus people say to stagger like this to avoid cracking along the board joints, but I would still have a long join running in a line across each row, so don't see how it helps.

    The whole house is being skimmed and I plan to screw in fixings at 230mm intervals.

    For the walls, the room heights closely match the board heights so I will lay full 12.5mm boards vertically and cut longways to suit the often irregular pattern of studs/battens that the timber frame company helpfully created.


    Does this all sound ok, or do you think I should have an early start tomorrow and spend a couple of hours screwing in extra noggins before my help arrives for the boarding party !


    Thanks

    Pete
    •  
      CommentAuthordjh
    • CommentTimeApr 24th 2018 edited
     
    Posted By: OracsRevengeMost internet advise says to lay the long side perpendicular to the direction of my metal web joists. Just want to be sure I stagger them correctly.

    It certainly makes sense since that way the long length of the PB sheet is supported at multiple points. In our case, we laid them parallel to our metal web joists but that was because we have resilient bars at right angles in between. We didn't use noggings and have had no problems.

    I plan to lay boards end on end across all the joists at one edge of the house (8m edge), cut the last board to size and then start the next row with a full board and head back towards the original side of the house, introducing a stagger between rows.

    We started the first row at one end (A) and finished with a part board at the other end (B). Then we used the offcut to start the second row at end A. Rinse and repeat. Unless your width is a multiple of 2.4 you will get a stagger.

    edit: somethiing to think about: we took all the offcuts and glued them to the back of the boards used for the walls to provide extra mass. We used Everbuild AC50. The result was almost no plasterboard waste to dispose of and we're very happy with the noise performance.
    • CommentAuthorowlman
    • CommentTimeApr 24th 2018
     
    Perhaps you could use djh's offfcut method for strengthening the long joins, between joists, as you go along, or from above? afterwards. Just don't use too big pieces thereby possibly creating a sag.
    • CommentAuthortony
    • CommentTimeApr 24th 2018
     
    Will be fine
    • CommentAuthorMarkyP
    • CommentTimeApr 25th 2018
     
    15mm boards are nice and stiff (and heavy!), I think British Gypsum have a table to give advice on whether noggins are recommended at different board thicknesses and from memory 15mm is OK at 600mm without noggins. If it makes you feel any better i used 15mm boards and didnt fit any noggins.

    remember Tony's tip, dont screw too close the wall intersection, this will allow the board to flex a bit with thermal expansion and mean it's less likely for the wall/ceiling joint to crack. I didnt do this and wish I had.

    15mm boards are hard work on a ceiling, it may be too late now but if you have a larger area to cover hire a board lifter, I did an 80m2 ceiling on my own using one, was a cinch.
  2.  
    Even with two of you a pair of these props makes life a whole lot easier. Well worth the investment (they'll still fetch something second hand).

    https://www.machinemart.co.uk/p/draper-expert-quick-action-telescopic-support/
    • CommentAuthorbhommels
    • CommentTimeApr 25th 2018 edited
     
    Is there a room above the ceiling? In that case I can really recommend to fit resilient bars between the joists and the layer(s) of plasterboard. Yes it means extra work, but the additional soundproofing you get from it is certainly worth it. The bars themselves are not expensive.
    Advice on how to fit can be found here:
    http://www.soundservice.co.uk/installation_resilient_bar.html
    • CommentAuthorTimSmall
    • CommentTimeApr 25th 2018
     
    You can use off-cuts from lightweight steel metal partition walling stud frame (should be available from local builder's merchants and can be cut with tin snips) at joins. We did this when using 12.5mm with 600 centres, no problems...

    Alternatively bits of ply or OSB offcut will also work if you have the space behind the plasterboard.
    • CommentAuthorborpin
    • CommentTimeApr 25th 2018
     
    I double tacked the dense board (can't remember the designation). With insulation as well, sound transfer is virtually nil. Joiner wasn't happy though....
    • CommentAuthordelprado
    • CommentTimeApr 25th 2018
     
    Doesn't it make sense to plan to leave a gap around the perimeter and fill with acoustic sealant of some sort?
    •  
      CommentAuthordjh
    • CommentTimeApr 25th 2018
     
    Posted By: delpradoDoesn't it make sense to plan to leave a gap around the perimeter and fill with acoustic sealant of some sort?

    I don't think there's anything wrong with that plan, certainly. It's what's advised for the walls in any case, so I guess it makes sense for the ceiling too.
  3.  
    Hi all,

    Thanks for the help, I started early this morning and followed the original plan, all went smoothly.

    Didn't have time to install anything special, but did leave a small gap around the permieter to allow for expansion.

    Heavy work, but there were 4 of us, so no problem.

    Film crew got in the way a bit, but other than that, no dramas !

    Cheers
  4.  
    Hi,

    For the ceilings on the 1st floor, I have GTEC fire resistant pink boards. Will these be ok ok their own on the bathroom/ensuite ceilings, or should I use some kind of moisture barrier paint?

    To have the pink boards and then another layer of moisture-resistant green boards on the ceiling would make the build-up too thick, hence looking at paintable options.

    I will be using the green boards on the bathroom/en-suite walls and a proper tile-backer board in the showers, it's just the ceilings I'm not too sure of.

    Thanks
    • CommentAuthortony
    • CommentTimeApr 30th 2018
     
    try it with ordinary paint first and see how you get on, it is fine in my bathroom but some people have problems, you can add layer of different paint if you need to.
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