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.




    • CommentAuthorluz13827
    • CommentTimeSep 2nd 2021 edited
     
    Hello, for our extension, we are planning to do a cavity wall, with partial fill insulation of EPS (EPS seems healthier choice than PIR).

    My question is, can we use regular EPS, e.g. https://www.roofingoutlet.co.uk/products/expanded-polystyrene-eps-70-1200mm-x-2400mm-x-50mm


    .. or is there something special about a version that is labelled specifically for partial fill e.g: https://www.jablite.co.uk/application/partial-fill-cavity-wall-insulation Only difference I can see is that this one comes in a smaller size board.
    • CommentAuthorMike1
    • CommentTimeSep 3rd 2021 edited
     
    Posted By: luz13827Only difference I can see is that this one comes in a smaller size board.
    Because it's cut to suit standard brick / block heights; better to minimise site cutting.

    Note that fitting partial fill is more dependent on conscientious bricklayers than full fill, though there is plenty of scope for any cavity fill to be be fitted very poorly.

    Given the choice, I go for a solid wall with external insulation.
    • CommentAuthorrevor
    • CommentTimeSep 3rd 2021
     
    Posted By: Mike1
    Posted By: luz13827Only difference I can see is that this one comes in a smaller size board.
    Because it's cut to suit standard brick / block heights; better to minimise site cutting.

    Makes it easier for the fitting of the cavity ties you would also have trouble cutting large boards to size getting them square and butting them up so no gaps. Don't believe you will get sufficient u value with 50 mm EPS think regs requires 75 mm pir but don't quote me. I went overboard with 100 mm T&G PIR in a 150 cavity when it was 50mm regs at time.
  1.  
    Posted By: Mike1Given the choice, I go for a solid wall with external insulation.

    +1
    • CommentAuthortony
    • CommentTimeSep 3rd 2021
     
    Or wider cavity with full fill eps
    • CommentAuthorphiledge
    • CommentTimeSep 3rd 2021
     
    Any cavity build with rigid insulation needs a high degree of attention to detail and unless youve got brickies that fully understand the BBA cert, has a good chance of being done wrong. If you need or want a cavity with rigid insulation then make sure you and your brickies understand the manufacturers BBA instructions. Pay the brickies on a day rate so you can stop the job anytime you want. Most importantly dont accept " we know what we're doing" until youve seen their work in compliance with the BBA cert.
    • CommentAuthorrevor
    • CommentTimeSep 3rd 2021
     
    Posted By: Peter_in_Hungary
    Posted By: Mike1Given the choice, I go for a solid wall with external insulation.

    +1

    We all have our reasons for favouring a particular approach. I am a traditionalist and favour a cavity every time. If the outer layer gets damaged physical or weather there is a protective barrier i.e space preventing ingress into the property. My BCO was an ex brickie and had worked in Germany on many an exterior insulated house but he still preferred the cavity approach and put me off filling the cavity as I mentioned to him I had seen insulation being blown into a cavity on a new build. I have no issue with exterior insulation if you create a barrier between it and the exterior by for example rain screen cladding. That way you get the best of both worlds, a belts and braces approach it also becomes more of a DIY job erecting a rain screen requires less skill than a render coat if you are doing the work yourself.
    • CommentAuthorluz13827
    • CommentTimeSep 3rd 2021
     
    Our builders were planning to use blockwork (I'm unsure whether high density or aerated) - with the internal finishes and an insulating render, I calculated that we could achieve the U value either way. If we stick with partial fill cavity, is the main thing to ensure that the builders butt the insulation very tightly to the inner wall, and then keep the cavity clear? Is there anything else we should be watching for? My husband will be onsite and monitoring so he will be able to keep an eye out, if he knows what to look for.


    If we went with solid wall, what type of blocks would be recommended? The only wider blocks I can see are 'foundation blocks'. Sorry, construction is fairly new to me, and I've learnt a lot already with the help of others, so appreciate people answering my basic questions! Part of the wall will be clad in zinc, so that will act as a rain barrier. Then the side we were planning to render.
    • CommentAuthorphiledge
    • CommentTimeSep 3rd 2021
     
    Posted By: luz13827Our builders were planning to use blockwork (I'm unsure whether high density or aerated) - with the internal finishes and an insulating render, I calculated that we could achieve the U value either way. If we stick with partial fill cavity, is the main thing to ensure that the builders butt the insulation very tightly to the inner wall, and then keep the cavity clear? Is there anything else we should be watching for? My husband will be onsite and monitoring so he will be able to keep an eye out, if he knows what to look for.

    All of the insulation manufacturers will have BBA certs that describe in detail how the walls should be built and how the insulation should be installed. If your chosen manufacturer hasnt, choose a different manufacturer.

    The approved plans will tell the builders which blocks they should be using, assuming youve got plans!
    • CommentAuthorMike1
    • CommentTimeSep 4th 2021 edited
     
    Posted By: luz13827Our builders were planning to use blockwork (I'm unsure whether high density or aerated)
    Never leave it to builders to decide what materials to use! You need someone qualified to specify everything.

    See also http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16963#Comment_288028
    • CommentAuthorrevor
    • CommentTimeSep 4th 2021
     
    Posted By: Mike1
    Posted By: luz13827Our builders were planning to use blockwork (I'm unsure whether high density or aerated)
    Never leave it to builders to decide what materials to use! You need someone qualified to specify everything.


    I totally agree. If you were doing a cavity wall then I could make some recommendations but I have no experience of a solid wall. I am somewhat puzzled as you make no mention of building control nor if you have planning perhaps it is a small extension. However you would need build regs approval either by submitting detail plans or serving a building notice. Who drew up you plans? whoever did whether an architect or a designer they should be able to advise you and submit the building regs application.
    • CommentAuthorjms452
    • CommentTimeSep 4th 2021
     
    Posted By: philedgewe know what we're doing


    I accepted that line a couple of times when I was younger and more trusting - Never again!

    Best countered with something along the lines of 'I think we'd both rather I was specific about what I want done before you've done it'
  2.  
    Posted By: luz13827If we went with solid wall, what type of blocks would be recommended? The only wider blocks I can see are 'foundation blocks'.

    The standard building block over here is Porotherm available in various widths. They are honeycombed clay blocks and are available in the UK. I recently put up an extension using 250mm Porotherm blocks with 200mm EWI. The 250 blocks are sufficiently load bearing.
    The walls finished up as in to out - 20mm render, 250mm Porotherm, 200mm EPS EWI and 5mm render/mesh and thin film acrylic render
    Much quicker (= less expensive) than cavity build and less to go wrong in terms of insulation workmanship
Add your comments

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

© Green Building Press