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insulating an existing roof

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  • 07-01-2009 1:38pm
    #1
    deargas
    Registered Users Posts: 58 ✭✭


    Like the rest of the country, I'm feeling the cold.

    I'm trying to figure out the best way to insulate the loft rooms. Unfortunately the roof and ceiling are already in place, and taking them off to add insulation is not an option.

    I do have access to the cavity in the rafters via the sides of the room, (storage areas), and I was thinking of trying to slide up some insulation between the rafters.

    when I looked at the existing insulation I could only laugh. It's around 10 - 15mm styrofoam boards, so practically none then.

    I did a little searching and came across aluminium foil insulation as a potential option.

    does anyone have any suggestions or recommendations of these products, or even where to get them in ireland.

    b & q supply 7.5m x 0.6 m rolls for EUR 55, so that's a start.


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    #2
    10-10-20
    Registered Users Posts: 7,168 ✭✭✭10-10-20


    Alu foil is a cod.
    Could you get this product into the gap? (Knauf Space Blanket)
    http://www.diy.com/diy/jsp/bq/nav/nav.jsp?isSearch=true&fh_search=5012061107531&selected=products&x=0&y=0

    Or this...
    http://www.diy.com/diy/jsp/bq/nav/nav.jsp?isSearch=true&fh_search=0000003716267&selected=products&x=0&y=0


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    #3
    deargas
    Registered Users Posts: 58 ✭✭deargas


    possibly,

    the problem is that my only access is from the bottom of the rafter, so I was looking at something a little rigid that I could slide up. I think the blankets would go up around 1 metre and then bunch like Y fronts.


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    #4
    lomb
    Registered Users Posts: 6,031 ✭✭✭lomb


    kingspan is what is ideal


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    #5
    RKQ
    Registered Users Posts: 2,292 ✭✭✭RKQ


    Kingspan, xtratherm or polycomp foil back high density insulation. 75mm should suit allowing for 50mm air ventilation gap. Friction fit between rafters os sloping ceiling. 300mm fibre glass, in 2 layers to attic!

    Aluminium foil / buble wrap insulations require 50mm air gap either side to reflect heat etc - so not as "thin" as assumed. I'd like to see an IAB Cert before purchasing.


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    #6
    deargas
    Registered Users Posts: 58 ✭✭deargas


    Thanks for that everyone.

    I've had a look in the building suppliers at the xtratherm stuff. It looks pretty good,

    I've got 110mm cavity between roof and plasterboard, with a 300mm span between rafters (old house), so the 70mm board is probably all I can fit in there.

    It's not going to be ideal as I will not be able to fit the stuff snugly, more of a slide manouver from the bottom up, but it'll be better than what's there.

    got a price for Xtratherm of EUR25 for 2.4m x 1.2m x 50mm from hardware store here in Galway. Does that seem reasonable?

    cheers again.


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