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Attic Insulation

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  • 18-11-2008 8:28pm
    #1
    Lex Luthor
    Registered Users Posts: 11,220 ✭✭✭✭


    I currently have 100mm of fibreglass insulation on my attic floor.

    I'm looking to increase the attic insulation.

    Can anyone tell me which would be more beneficial?

    Adding an extra 200mm thickness of fibreglass or eco wool to the floor or putting this in the roof space?


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


    "This" would be my choice, cut with circular saw and friction fitted - 2 layers of 50 or 60mm will allow attic to be used for storage. Old fibre glass can be re-laid over same in non-storage areas.

    Fibre glass - 150mm between joist and 150 - 170mm laid perpendicular to joists. This would be more economical. Mask, gloves etc required to lay.


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    #3
    Lex Luthor
    Registered Users Posts: 11,220 ✭✭✭✭Lex Luthor


    RKQ wrote: »
    "This" would be my choice, cut with circular saw and friction fitted - 2 layers of 50 or 60mm will allow attic to be used for storage. Old fibre glass can be re-laid over same in non-storage areas.

    Fibre glass - 150mm between joist and 150 - 170mm laid perpendicular to joists. This would be more economical. Mask, gloves etc required to lay.

    Thank RKQ. So you would recommend the roof insulation over the extra floor insulation?


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    #4
    jack of all
    Registered Users Posts: 2,376 ✭✭✭jack of all


    Be aware that if you opt for Kingspan fitted between rafters (I assume this is implied?) this would impact on ventilation of the roof space, unless arrangements are made to ensure that adequate cross ventilation is provided. Personally I'd opt for additional fibreglass- inexpensive, quick to fit and no modification of roof ventilation required, payback time is very short.


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


    RKQ wrote: »
    "This" would be my choice, cut with circular saw and friction fitted - 2 layers of 50 or 60mm will allow attic to be used for storage. Old fibre glass can be re-laid over same in non-storage areas.

    Fibre glass - 150mm between joist and 150 - 170mm laid perpendicular to joists. This would be more economical. Mask, gloves etc required to lay.

    I assumed "this" implied putting foil between joists. Installing between rafters is a major job compared to laying between joists - expensive and time consuming.


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    #6
    Lex Luthor
    Registered Users Posts: 11,220 ✭✭✭✭Lex Luthor


    ok I'll start with the fibreglass on the floor running it perpendicular to the existing fibreglass.

    Any recommendations on any? Is there anything I should be looking at on the packaging that distinguishes one type to another in terms of effectiveness?


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    #7
    jack of all
    Registered Users Posts: 2,376 ✭✭✭jack of all


    RKQ wrote: »
    I assumed "this" implied putting foil between joists. Installing between rafters is a major job compared to laying between joists - expensive and time consuming.
    Fair enough, but I wouldn't suggest using a circular saw for cutting this stuff, a regular panel saw (hand saw) is best.


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    #8
    RKQ
    Registered Users Posts: 2,292 ✭✭✭RKQ


    Hand saw is fine if you can cut a 2400mm straight line and have lots of time. Otherwise a table, a clamp and a circular saw is idea - perfect edge, no gaps.

    Circular saw is extremly fast in my experience. Hand saws and stanley blades tend to bend easy and its easy to go crooked!


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