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Attic/Dormer Insulation

  • 07-09-2010 08:57AM
    #1
    Registered Users, Registered Users 2 Posts: 11


    Morning everybody,

    I'm renovating my house and doing a loft conversion on it. Got a quote for spray foam inaulation and I nearly fell over!

    I'm sure there are loads of you who can answer this - but what is the best value insulation. I know spray foam is great but can the same insulation and airtightness be achieved with rockwool and insulated slab.

    Can someone please help cos I've no idea where to start as this is all very new to me?

    Thanks,
    Greg


Comments

  • Moderators, Home & Garden Moderators, Regional Midwest Moderators, Regional West Moderators Posts: 16,716 Mod ✭✭✭✭yop


    Moved from Interior Design.... insulation not really interior design ;)


  • Registered Users, Registered Users 2 Posts: 11 Boumticlad


    Thanks Yop - Didn't know where to put it....


  • Registered Users, Registered Users 2 Posts: 2,292 ✭✭✭RKQ


    It is quite possible to achieve air tightness with fibre glass insulation & plaster slab. Have a look at Siga or ProClima web sites. These Manufacturers give full details on how to achieve same, with useful photographs to help you.

    Retro-fit in a loft is possible also. This artical will also help.
    http://constructireland.ie/Articles/Ventilation/How-why-to-achieve-excellence-in-air-tightness.html


  • Registered Users, Registered Users 2 Posts: 11 Boumticlad


    Thanks for that. I've had a look at this and there's no way I can afford the spray foam insulation. I'm down to 2 potential insulation suppliers. I'm looking at the Quinn-therm insulation and the Aerobord Aerodorm Platinum.

    Any opinions on which of these is best - or should I consider something else? Thanks


  • Registered Users, Registered Users 2 Posts: 2,292 ✭✭✭RKQ


    Have a look at this tread
    http://www.boards.ie/vbulletin/showthread.php?p=58058495#post58058495

    IMO if you intend to insulate between your rafters then use a foil faced insulation board. These boards can achieve the same insulation value with a thinner board - important if your rafters are only 150mm deep ( as you will need to leave a ventilation air gap of 50mm between the felt & new insulation).

    Retro-fit can be difficult but very worth while. I'm not sure of your exact requirements but 2 no. 50mm sheets of foil backed insulation, friction fitted between rafters, with a 25mm layer to the underside of all rafters, could work well. PM for details.

    Sheets can be cut to rafter width with circular saw, for a neat edge - also makes it easier to get them thru attic hatch.

    Hope it works out. Good luck.


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