1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Insulation requirements in roof space (integral garageconv)

Discussion in 'Roofing and Guttering' started by kitessurfer, 3 Aug 2008.

  1. kitessurfer

    kitessurfer

    Joined:
    15 Mar 2008
    Messages:
    166
    Thanks Received:
    1
    Location:
    Kent
    Country:
    United Kingdom
    Hi, would someone remind me please what thickness insulation I should be laying in the roof space of my intergal garage conversion,20cm? 27cm?
    Should it be between joists or should I leave gap between joists then insulation on top. I gather there are different rules depending whether this is topping up existing insulation or new job. This is a new ceiling joist construction as part of garage conversion under building notice.
    thanks
    KS
     
  2. Sponsored Links
  3. noseall

    noseall

    Joined:
    2 Feb 2006
    Messages:
    42,613
    Thanks Received:
    2,638
    Location:
    Staffordshire
    Country:
    United Kingdom
    if the whole of the converted garage is integral then the only insulation requirements are for sound reduction.

    100mm of fiberglass or mineral wool should do.

    if the joists are formed from a prefabricated matrix then you may not need acoustic protection at all. ;)
     
  4. kitessurfer

    kitessurfer

    Joined:
    15 Mar 2008
    Messages:
    166
    Thanks Received:
    1
    Location:
    Kent
    Country:
    United Kingdom
    ..must have been asleep,Imissed the vital info, its part integral as below in pic;
    :oops:

    #
     
  5. noseall

    noseall

    Joined:
    2 Feb 2006
    Messages:
    42,613
    Thanks Received:
    2,638
    Location:
    Staffordshire
    Country:
    United Kingdom
    you will need minimum 270mm of insulation in the ceiling space.

    we normally go with 150mm between joists and 150mm across. saves buying differing thicknesses.

    use foil backed plasterboards on exposed joists.
     
  6. kitessurfer

    kitessurfer

    Joined:
    15 Mar 2008
    Messages:
    166
    Thanks Received:
    1
    Location:
    Kent
    Country:
    United Kingdom
    Thanks Noseall, I've aquired a lot of insulation over the last months from legitimate sources (builders skips next to relatives houses). Its amazing how much good new stuff is thrown away during building work. Obviously I won't be able to get 30cm towards the soffit end of the roof. I know you can purchase plastic trays to sit on the insulation to ensure the flow through of air to the soffit, any ideas on this? Are there any diy alternatives? I was thinking to cut back on the thickness in line with the roof line and leave as is. Thanks for any thoughts on this, if you read it ofcourse.
    KS
     
  7. noseall

    noseall

    Joined:
    2 Feb 2006
    Messages:
    42,613
    Thanks Received:
    2,638
    Location:
    Staffordshire
    Country:
    United Kingdom
    the eaves area of the roof is the most vulnerable, as this is the area where your ceiling is closest to the roof tiles and the outside world. cold bridging can be at its worst at this junction.

    do not skimp here.

    if you have existing soffit or over-fascia vents then you can push fit eaves ventilators between the joists to assist airflow. then push the insulation in as normal.

    if you don't have ventilation at the soffit detail at all, then you would be advised to fit some vent tiles and worry not about eaves ventilation and all that goes with it.
     
  8. kitessurfer

    kitessurfer

    Joined:
    15 Mar 2008
    Messages:
    166
    Thanks Received:
    1
    Location:
    Kent
    Country:
    United Kingdom
    Thanks again Noseall, I see what you mean as you state the ceiling is closet to the roof there, I think I'll purchase the eaves vintilator to assist. I do have new round suffit vents fitted but only at about 80cm gaps, (they should be 50cm intervals). I'll leave them as is for now. I think the two vent tiles nicely vent the roof space sufficiently...
    photo shoing roof vents. The furthest on the right is for extraction fromwc/shower. There's no further vent on the right as this roof space above the door is bricked off.
     
  9. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
  10. Sponsored Links
Loading...

Share This Page