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

Garden outbuilding, insulation and more???

Discussion in 'In the Garden' started by jonnypron, 20 Jun 2017.

  1. jonnypron

    jonnypron

    Joined:
    18 May 2017
    Messages:
    66
    Thanks Received:
    0
    Location:
    Thames Ditton
    Country:
    United Kingdom
    • Please see https://www.diynot.com/diy/threads/share-your-diy-projects-with-us-no-queries-please.74081/
    Hi there.

    I've had some very helpful advice from this forum recently, but need some more if possible.

    Just wanted to confirm the insulation specs. The plan is currently;

    Floor
    75mm PIR insulation laid directly on concrete with glued battens spanning front to back as a fix for scaffold boards which I intend to use as the flooring (sanded down)

    Walls
    75mm rockwool slab or flexi? in-between stud work as 100mm is too deep for 95mm 4x2 timber. Do you need an air gap for this? I presume not as air can flow through it? Obviously on the cold side there will be membrane, battens (for air flow) then cladding.

    Ceiling
    100mm PIR in-between rafters, air gap, then OSB and EPDM.

    Just not sure on the rock wool type. I want to get wiring on the stud work too so how does this work if the insulation is tight in the space?

    Also does anyone know anything about how the membrane finishes with the roof? The rafters are flush with the stud wall as didn't want overhang as such, just wanted minimum possible flashing over the top. How does the membrane sit at the top edge... does it overlap onto the roof sheeting before the EPDM? Does the ventilated area in the walls join up with the ventilated area in the roof, so that the membrane is effectively covering both and breathing for both gaps?

    Maybe I should post this last bit in the roofing section. Any advice on the other points much appreciated.
     
  2. Sponsored Links
  3. motorbiking

    motorbiking

    Joined:
    31 May 2016
    Messages:
    5,715
    Thanks Received:
    641
    Country:
    United Kingdom
    Personally I'd go with 75mm celotex or similar as it also has moisture barrier. Tape the cables in silver tape to protect them
    [​IMG]
     
  4. jonnypron

    jonnypron

    Joined:
    18 May 2017
    Messages:
    66
    Thanks Received:
    0
    Location:
    Thames Ditton
    Country:
    United Kingdom
    would like to, but it's pretty expensive and also need some sound proofing which celotex doesn't really have. Interesting you've laid timber directly on the concrete. Has the slab been down a while i.e. dried out completely or you used a DPC under the floor joists?
     
  5. motorbiking

    motorbiking

    Joined:
    31 May 2016
    Messages:
    5,715
    Thanks Received:
    641
    Country:
    United Kingdom
  6. jonnypron

    jonnypron

    Joined:
    18 May 2017
    Messages:
    66
    Thanks Received:
    0
    Location:
    Thames Ditton
    Country:
    United Kingdom

    Attached Files:

  7. geraldthehamster

    geraldthehamster

    Joined:
    7 Feb 2010
    Messages:
    2,974
    Thanks Received:
    320
    Country:
    United Kingdom
    I don't think Celotex contains solvents that would attack cables, does it? Unlike polystyrene.

    Cheers
    Richard
     
  8. motorbiking

    motorbiking

    Joined:
    31 May 2016
    Messages:
    5,715
    Thanks Received:
    641
    Country:
    United Kingdom
    You know what.. I had so much conflicting info, that it was easier to just tape it in foil tape. Having the added advantage, that it didn't fall on my head or get trapped while trying to put the plaster board up
     
  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