Home  5  Books  5  GBEzine  5  News  5  HelpDesk  5  Register  5  GreenBuilding.co.uk
Not signed in (Sign In)

Categories



Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.
Buy individually or both books together. Delivery is free!


powered by Surfing Waves




Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
 Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.




Housing - Renovation: PIR vs EPS Rafter level Insulation

Bottom of Page

1 to 4 of 4

  1.  
    • CommentAuthoralm
    • CommentTimeDec 27th 2022
     
    Hi,

    Sorry, this is a bit of a lazy question on my part. I'm getting ready to insulate our roof, at rafter level. The rafters are very thin, so the plan was to just fix 150mm celotex under them, taped and sealed, battens and then plasterboard.

    I've also seen some comments on using EPS instead, and how this might be a better material. Would anyone recommend one over the other for this detail?

    The EPS appears significantly cheaper, I know the U-Value will be slightly less which I'm happy to accept, are there any other disadvantages?

    Cheers
  2.  
    When ever I have done the price/performance for slab type insulation EPS has always come out way ahead.

    I don't see any down side to using EPS in this application, accepting a lower U value if you compare like thicknesses. If you can accept to up the thickness of the EPS to get the same U value then you will still come out cheaper.

    Of course my location is a bit different to yours so YMMV
  3.  
    EPS is definitely poorer insulation value than PIR, you'd need 250+mm of EPS to get the same U value as your 150 PIR. At that thickness it becomes difficult to get fixings etc long enough.

    Mineral wool or fibreglass batts have similar insulation value as EPS and are cheaper, and their manufacturing has much less enviro impacts (especially the recycled glass ones).
    • CommentAuthoralm
    • CommentTimeDec 31st 2022
     
    Thanks both for getting back to me, I don't think we'd have the head room (or the patience and extra time!) for 250mm, so might be back to the PIR.

    Appreciate the responses, it's saved me a good few hours research!

    Anna

1 to 4 of 4

  1.  
Add your comments

    Username Password
  • Format comments as
 
Back to Discussions Top of Page
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press