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.

    I'm installing 200mm of mineral wool insulation. I bought rolls of mineral wool from a well known national brand. The wool is sold as 200mm thick, though arrives tightly wrapped on a roll.

    The problem is that, when unwrapped, it doesn't fluff up to anything like 200mm thick. I left some unrolled on the floor and after a weekend it had fluffed up to 100-120mm thick. Obviously this doesn't fill the space I have to the required thickness.

    Am I doing or expecting something wrong? Anyone else noticed this? Anything I can do, other than buy more rolls and double it up?
    • CommentAuthorandyman99
    • CommentTimeOct 20th 2019
    Could have written the above post myself, installed 9 rolls this week and had the same experience. I felt that some bits expanded better than others, possibly the start of the roll that was less kompressed?
    • CommentAuthortony
    • CommentTimeOct 20th 2019
    I reckon wrongly labelled rolls, take them back
    Last time I installed some 100mm, again from a well-known brand, I had 2 packs (6 rolls) which I had had for nearly 2 years, and 2 packs just bought. The newly-bought stuff 'recovered' fairly well, but the older stuff not so. Had the same problem with recyc plastic, where the '100mm' roll never reached beyond about 70mm.

    A pain if you are DIY-ing. Even more disturbing if you are installing for others. If you have budgeted for 2 layers of 100mm (=200mm, of course, except that it potentially doesn't) you might have to pay out of your own pocket for a 3rd layer, to satisfy both the customer and BCO.

    Sometimes 'wrestling' it a bit gets it a bit beyond the 'self-recovery' thickness.
    • CommentTimeOct 20th 2019
    Posted By: tonyI reckon wrongly labelled rolls, take them back


    I'd leave some unrolled for a couple of days, just to be sure it doesn't slowly expand.
    • CommentAuthortony
    • CommentTimeOct 20th 2019
    It usually expands instantly
    • CommentAuthorandyman99
    • CommentTimeOct 21st 2019
    The various thicknesses are also different lengths on the roll. Fairly sure the length was about right for 200mm thickness. so if wrongly packaged they also would have had to wrongly cut as well. Some definitely expanded better than others for no apparent reason. Longer storage sounds plausible, will check expansion in a week or two I cant face going up there again atm.
    • CommentAuthorvord
    • CommentTimeOct 21st 2019
    I pulled the top of mine upwards and shook it around a bit as I installed it and it seemed to fluff up perfectly evenly to the right thickness. True enough it doesn't do that by itself after unwinding from a tight roll.
Add your comments

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

© Green Building Press