Internal Wall PIR Insulation Install Cost Via Tradesman

Discussion in 'Eco Talk' started by Bazzy, Jul 30, 2021.

  1. Bazzy

    Bazzy New Member

    Hi All,

    I hope this is OK to ask her since I would like to get input from people in the Industry!

    We have a room built on top of a garage conversion whose longest exterior wall (Solid & NNE Facing) is very thin - only about 100mm or one brick thick with no insulation so it is a massive source of energy loss. The room is width limiting & due to boundary issues, it is not possible to apply external insulation.

    We aim to therefore have installed 62.5mm PIR Insulated Plasterboards via the Dot/Dab method (to save space by not battening).

    The wall dimensions are Length 4.9m x Height is 1.95m.

    Can anyone please kindly advise me on what sort of total cost/quote I can expect to have a tradesman install the insulation please? It would mean:

    1) Removing The Skirting
    2) Applying The Plasterboard Insulation & Properly Sealing
    3) Plaster Skimming For A Smooth Wall Finish
    4) Re-attaching the Skirting.
    5) Anything Else The Process Might Usually Require

    A possible future issue that has come to mind is that the room currently has laminate flooring so I presume the insulation will be installed on top - is that correct? If so this would make it very difficult to change the flooring in future to another type so would like to ask, what would be the best way to mitigate against this when installing the insulation to allow future changes of the room floor easily?

    I have attached an overhead sketch of the room for visual reference to help aid further & would be deeply grateful for any help/advice & input!

    Many Thanks!

  2. Jimbo

    Jimbo Screwfix Select

    If it's solid all the way round then it would be best to fit insulation all the way round too. Worth thinking about the floor - there will be a cold bridge under the floor boards (as still single skin there). I would lift the finish floor and complete gut the room, lift the floor boards and add some fibre glass around the perimeter, then do PIR backed board all the way round (hack off plaster in the window reveals to limit the build-out over the frames), and finally skim the lot. Will cost quite a lot to do I would think.

    But, how is the room protected from moisture ingress through the solid walls?

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