roof insulation

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  • roof insulation
  • cynic-al
    Member

    I’m getting a stack of work done on my house…part of which is to be plastering over the artex ceiling in my kitchen.

    The roof above is flat and there is no insulation (1920’s flat in Edinburgh). I am now thinking of just pulling the plasterboard down and insulating it then fitting plasterboard which should be way easier to plaster.

    Given it’ll be the most heated room in the flat, it’s got to make a significant difference to heating & bills yes???

    footstomper
    Member

    If you have enough hieght then I would suggest leaving the existing cieling in place, put up a false one directly underneath using 3″ x 2″ timber then insulate – plasterboard – skim – paint job done without loads of mess.

    Premier Icon wwaswas
    Subscriber

    what fs said but you may not even need the studs – you can get 15mm insulation panels that really make a difference so those plus another layer of 15mm plasterboard and longer screws through to the existing ceiling joists and you’ll be fine and you’ve only dropped the ceiling 30mm.

    If you do choose to insulate make sure you leave an air gap between the insulation panels and the underside of the roof and that there’s sufficient ventilation for the resulting voids.

    TandemJeremy
    Member

    Mattoutandabout is your man for this sort of thing.

    Pulling down old ceilings is very messy. If you can insulate without removing the old ceiling it would be better from that point of view.

    Premier Icon Stoner
    Subscriber

    Ive used polystyrene backed pplasterboard on some of the internal outside walls of my house. Its ot 10-155mm plasterboard backed by 20mm-30mm of polystyrene. Easy to fix using dabs of bonding adhesive.

    found elsewhere:

    As Mike has suggested with 50mm PUR and 12.5mm plasterboard you’ll reduce the wall U value from around 2.1 to 0.4W/m2K or so.
    That’s giving you an 80% saving through the walls which is tremendous. On your property though I’d imagine that if using a rigid foam thermal board you’ll need to use timber battens so the total build up will be in the region of 85mm.

    Alternatively Aerogel will give you a few thin choices, the first would be a 2 layers of 10mm option ready bonded to plasterboard or Fermacell, this would take the U value to around 0.52W/m2K thus giving a saving of 75%. Both solutions can be fixed directly to the wall. Applied thickness is then 30mm.
    A utility company is supporting the Fermacell option with funding through the CERT scheme so that could be very cost effective.

    Another solution is to use a single layer of 10mm Aerogel with wet plaster, that would give a U value of 0.8W/m2K and a saving therefore of 60%.

    Premier Icon matt_outandabout
    Subscriber

    If I were you Al, I would stick in as much as you can – pull the old ceiling down, leave an air gap under (I assume sarking board in the ‘burgh)of about 40mm, then a soft batt of rockwool, then as said above a foam insulated plasterboard or aerogel right across the whole lot.

    I would not batten it out as first suggested – you end up loosing a lot of the effectiveness of your insulation by cold bridges through the timber.

    Insulation is (relatively) cheap at present, especially compared to increasing energy costs.

    And yes it will make a huuuuge difference.

    Premier Icon takisawa2
    Subscriber

    matt_outandabout…any experience of insulating walls ?
    Any chance you could drop me an email if you have.
    Looking for some advice on insulating shuttered concrete walls in a 60’s council semi.
    PT

    Premier Icon ransos
    Subscriber

    I’ve just had the same work done as Stoner – 20mm of polystyrene plus 10mm plasterboard on the walls. The builder tells me that it’s normally fitted to ceilings and makes a big difference to heat retention.

    cynic-al
    Member

    Thanks all – I don’t mind ripping the ceiling down as the room is bare (no flooring, units etc) so the mess is fine, and would save me lowering the ceiling/creating a new framework of 3×2.

    There’s a 1′ void to the roof (which is adjacent to and “breathes into” a pitch roof/attic space) so I’d thought I could fire up proper loft insulation into that then just fire plasterboard on existing battens – gotta be better insulation than 30mm of polystyrene etc (which can’t be a great fire risk for insurance purposes?).

    Thing is I should really do the same to the other 2 rooms under the flat roof – I’ve just had the ceiling papered in the larger of them…

    Premier Icon matt_outandabout
    Subscriber

    Takisawa – yes, lots, like every day!

    You need:
    http://www.greenbuildingforum.co.uk/newforum/ (and search)

    I can also email you some EST guids on how to do it (they are very good)

    m.robinson AT natural-building.co.uk

    cynic-al
    Member

    Oh and it then sounds like I should also fire some insulation into the 4″ void between the external wall and its new plasterboard?

    Chalkyslide
    Member

    I’d recommend getting some local expert advice on the matter – last thing you want is to form a “cold” roof with inadequate ventilation which could lead to condensation and rot to the roof construction over time. Most modern flat roofs are “warm” roofs (i.e insulation laid over the top of the joists) to help avoid a dewpoint within the structural depth of the roof.

    For some independant advice maybe try googling TRADA and give them a call.

    cynic-al
    Member

    Cheers. My builder’s pretty good so I’ll ask him

    Premier Icon matt_outandabout
    Subscriber

    oops, I missed the bit about it being a flat roof – ram it up against the underside in which case, and make sure you use foam without gaps underneath.

    email me some pics if you want or chuck em on flickr.

    spooky_b329
    Member

    I ripped down my uninsulated kitchen sealing…replaced the plaster and lathe with 2″ polystyrene and plasterboard with an air gap to the tiles, can’t believe the difference after the recent snow…the first half is the insulated kitchen, second half is uninsulated bathroom.

    Insulated V Uninsulated Roof

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