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


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.

    • CommentAuthordelprado
    • CommentTimeJun 16th 2018
    I know expansion tape isn’t just for expansion but is also a means to stop the slab transferring heat into the walls, but given that my internal walls are the only thermal bridge through the foundations now (my external walls are being internally insulated) I think it might be helpful to put some heat into those internal walls to reduce condensation risk?

    Does anyone have any wisdom?

    • CommentAuthorgyrogear
    • CommentTimeJun 16th 2018
    Just to be clear, are you proposing to put the insulating tape under or over the edge insulation ?
    and which way is the shiny side going to go ?

    • CommentAuthortony
    • CommentTimeJun 16th 2018
    No need and no point
    • CommentTimeJun 16th 2018 edited
    You lost me at
    expansion tape ... is ... a means to stop the slab transferring heat into the walls
    • CommentAuthorgoodevans
    • CommentTimeJun 18th 2018
    I think he means the perimeter foam (25mm or so thickness) that surrounds the screed slab.
    • CommentAuthortony
    • CommentTimeJun 18th 2018
    Outside walls only
    • CommentAuthordelprado
    • CommentTimeJun 18th 2018
    Yes I am referring to the expansion foam stuff that is in a big roll.

    1. D you need an expansion on the inside walls to stop cracks or is on the outside only fine

    2. If you don’t do it on the inside, assuming the answer to 1 is that you don’t need an expansion joint all the way around, so you lose too much heat through the inside wall without the foam performing its secondary function as a thermal break?
    • CommentAuthorMarkyP
    • CommentTimeJun 18th 2018 edited
    the foam roll is I think principally an expansion joint detail. It is often a contractual requirement for screeds laid over UFH, I assume owing to the potential for greater amounts over thermal expansion and to create a movement space where it meets a wall. I had an anhydrite screed laid, and this detail was required as part of the contract so I didn't give it a great deal of thought. Whether this is really necessary or just another bit of trade practice that has become standard without ever really being justified, I don't know.

    10mm of foam isn't much of a thermal break. If you had screed laid on insulation and a cold bridge typical of a cavity wall on the inner leaf, then it would make sense to use some insulation up the face of the inner leaf to height of the screed to isolate it. I used 25mm PIR (and the foam roll was installed over that by the screed installer). With backing plaster and skirting, the inner leaf was later built out such that the top of the insulation and foam was just hidden from view. This only mattered because we had microtopping (think posh smoothing/levelling compound) laid on the screed and I needed to ensure the skirting came over the finished floor surface. If you are tiling/carpet/wood flooring then you'd cover whatever insulation might peep out anyway.
Add your comments

    Username Password
  • Format comments as
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   

© Green Building Press