Insulated plasterboard not wide enough

Discussion in 'Builders' Talk' started by Rozza2021, Dec 6, 2021.

  1. Rozza2021

    Rozza2021 New Member


    I am fixing insulated plasterboard to 2 chimney recesses in a bedroom, however the boards (provided at 120cm wide) are about 5cm narrower than the recessed wall, meaning there will be a gap between the board and the chimney breast.

    The only way around this i can see is to cut the boards lengthways, rather than using them as provided, however this creates 2 problems - there will be 2 joints between the cut boards as the ceilings are quite high so i'll need 3 sections (2 large sections and a final section at the top), and also the way the plasterboard is stuck to the insulation creates a slight overhang of plasterboard, which will result in a 2-3mm gap between sections of board, thus creating a potential cold spot.

    Has anyone else experienced this?

    The alternative is to stick the whole board in one piece, and fill the 5cm gap on the side with something else?
  2. Jiml86

    Jiml86 Screwfix Select

    Or buy more boards and rip to suit.
  3. Wayners

    Wayners Screwfix Select

    Fill and gaps with expanding foam.
    Can stick boards on with it too.

    B@Q sell a metal gun for £10 in building section not around the paint / filler section where there is a plastic gun for £8 ish.

    I'd probably use board foam as it hardly expands and if required shove a silicone mastic tube nozzle (push on) it's a hack but works to get in gaps if the supplied pipes are a bit flimsy.
  4. CGN

    CGN Screwfix Select

    Either way will be fine...don’t overthink it
    and as Wayners has said, a squirt of expanding foam if necessary. You can trim back the board to the foam if they’re not totally flush, and you’ll probably find that the wall to ceiling is out of square anyway.
  5. MRY

    MRY Active Member

    I like that, but maybe use sticky foam rather than ordinary expanding, and the gun I bought not long ago, a Faithfull Heavy-Duty Foam Gun (Full Non Stick Body) is £22 and very, very good indeed. The price of sticky foam is shocking, I bought a box of 12 from "somewhere online" and it was about £65 delivered! Everbuild Constructa. That's also good stuff. I tried a tin of Screwfix's "no nonsense expanding sticky foam", which was also OK, and a nice orangy-pink colour.
  6. CGN

    CGN Screwfix Select

    instastik is one of the best as it dries very quickly.?
  7. Rozza2021

    Rozza2021 New Member

    Dont overthink it? Good one ;-)

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