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.




  1.  
    Best value fixing foam for foil backed boards to painted walls? And maximum thickness it can be used at?
  2.  
    I would really not use any sort of glue alone on painted walls. If the paint comes off, so do the boards! I use http://www.screwfix.com/p/no-nonsense-expanding-sticky-foam-gun-grade-750ml/6576h - £7.99, or £7.19/can for 3 or more.
  3.  
    I intend to use mechanical fixings also...
  4.  
    Ah! That's OK then!
  5.  
    <blockquote><cite>Posted By: Nick Parsons</cite>I would really not use any sort of glue alone on painted walls. If the paint comes off, so do the boards! I use http://www.screwfix.com/p/no-nonsense-expanding-sticky-foam-gun-grade-750ml/6576h - £7.99, or £7.19/can for 3 or more.</blockquote>

    <blockquote><cite>Posted By: Nick Parsons</cite>I would really not use any sort of glue alone on painted walls. If the paint comes off, so do the boards! I use http://www.screwfix.com/p/no-nonsense-expanding-sticky-foam-gun-grade-750ml/6576h - £7.99, or £7.19/can for 3 or more.</blockquote>

    What about using Unibond or similar?
    • CommentAuthorJSC
    • CommentTimeAug 3rd 2016
     
    By unibond do you mean PVA? simply wont work; neither surface are 100% flat and the PVA will not bridge the gaps.

    I have used the screwfix foam and it is fine. Have to put more plasterboard up soon and will be using this method again.

    Speaking from experience ONLY use 100% flat insulations boards; no bends, creases or the like; they do not stick to the wall well; the bend pulls the boards off the wall (no matter how much you try to remove the bend beforehand).

    If you are plaster boarding on top, stagger the plasterboard relative to the insulation board
  6.  
    I have access to plenty of fischer b2 and the firestop foam, will that work?

    I have rang fischer and they have said none of their foams are suitable....
  7.  
    How do you prep painted walls ready for foamed on IWI then?
    • CommentAuthorMarkyP
    • CommentTimeAug 3rd 2016
     
    I think there are foams made specifically for this purpose. That must imply that the foam bond is rated to be adequate to hold the weight of the board. It will also probably mean the foam is relatively fast to cure and low expansion (i.e. you wont come back in the morning to find all your boards are wobbly becuase they have been pushed 50mm further of the wall as the foam kept expanding.
  8.  
    ''How do you prep painted walls ready for foamed on IWI then?''
    If you want to be 100% sure of the bond of the board to *the wall* (not just to the paint), you take the paint off! Sorry! Unless it's very powdery paint even PVA (usually regarded as the universal panacea) will only make you feel better. It won't improve the bond of the paint to the wall, so if that's weak, crash....

    Mech. fixings? Structural skirtings, covings and dado rail?
  9.  
    Is the screwfix stuff actually designed for this purpose? Surely the foam is more to keep the board plumb and the mechanical to stop it falling?
  10.  
    Kingspan have sent me the follow instructions
  11.  
    If the adhesive lets go, 2 fixings per board won't stop it flapping much!

    No Nonsense Sticky foam ''Can be used as an adhesive for fixing large sheet materials''

    On the other hand I use it for sticking foil-each-side Pu boards, followed by battens with mech fixings, followed by boards, so it only has to keep the boards still while I faff about.
    • CommentAuthorJSC
    • CommentTimeAug 3rd 2016
     
    There are foams for different purposes. You need an (adhesive) foam that is specifically deigned for attaching plasterboard and the like; the expansion on these is minimal. Dow do one (its in my garage!); they take a LITTLE bit of finding.

    People do not bat an eyelid at having plasterboard secured with only dot and dab (a glue) but people get the wobbles when you glue the same board with a dedicated foam. I don’t get it...

    If the adhesion of your paint onto the wall is very good I would just go for it. I did and nothing has fallen off the wall! :devil: Use mechanical fixings just as a backup if you are worried.....
  12.  
    The best way to make sure the board/foam/paint/wall interface won't give way is to use battens and screws. The paint is the weakest link - how many layers? or intermixed types of paint?
  13.  
    Any idea how many sheets a 750ml tin secures and how many 'dabs' per board. Just so I can work out if more cost effective to foam or batten on?

    I have my composite boards arriving tomorrow so need to have appropriate fixing method in place.
  14.  
    Posted By: VictorianecoAny idea how many sheets a 750ml tin secures and how many 'dabs' per board.
    That depends...sorry. Firstly if your walls are uneven or tilt and you want to make them plumb you can quickly use up a lot of foam. Also if you are worried about the current paint then you can use more say double. So it really does depend. Also I use lines of the stuff not dabs! Perimeter and horizontal usually. Will be putting some up myself on Sat, onto a very dusty uneven wall. I might use a combination of methods. Glue, foam and just a few fixings; the later more to stop expansion sending things wonky and to get it plumb.
  15.  
    Posted By: VictorianecoAny idea how many sheets a 750ml tin secures and how many 'dabs' per board. Just so I can work out if more cost effective to foam or batten on?

    Probably 30% to 50% less than it says on the tin - which is rated at optimum usage to make the product look better than the rest of the market place. - Think mpg quoted by car manufacturers !!
    • CommentAuthorFred56
    • CommentTimeAug 3rd 2016
     
    I use the orange coloured fixing foam I think it is Soudal brand and I get from Ironmongery Direct but it's available elsewhere. My method is odd, it so I'm told. I just use it to stick the insulation sheets in place and then I counter batten. It creates a service void to run cables then I screw the plasterboard or fermacell to the battens. I would guess I get four or five sheets to the can. I can vouch for the fact that it is very strong. You can't get the boards off whole in the event of an error. It you try it with foil faced board the foil gives before the fixing foam. Grab is minimal though so you gave to prop the in place but it goes off quite quickly. It's the only stuff I have used that can glue polyurethane foam and expanded polystyrene. I've even glued off cuts together to form wider pieces. It's useful but probably horribly bad for the environment.
    I'm sure it will hold your composite boards but as others have said, assuming the paint's does too. Be ready with the props. I don't dab, I squiggle all over.
    •  
      CommentAuthorfostertom
    • CommentTimeAug 4th 2016
     
    A builder friend says he doesn't trust the bond between foam board and foil facing - has seen plenty of foil facings coming loose by themselves even before fixing. So even if the foil face is foamed to background, the board may fall off the facing. Any comments?
    • CommentAuthorDarylP
    • CommentTimeAug 4th 2016
     
    if you clean the foil-faces, dust free, with a damp sponge, the joint will not fail! The foil-facing may delaminate from the C....x XR product, but the foamed joint is strong.
    However depending on the orientation of the board, the PIR - foil-face may not be stressed? I have foamed 200mm boards vertically, the foil-face did not shear.... :cool:
    • CommentAuthorRick_M
    • CommentTimeAug 4th 2016
     
    If you're worried about the paint being the weakest link you could see how strong it is / get rid of the weakest parts with a stiff brush. Or a wire wheel on a grinder. And if it does fail you could come back and add more fixings later.

    I went for grids / lines of adhesive rather than blobs and used Soudal adhesive.
    • CommentAuthorDave_07968
    • CommentTimeAug 11th 2016
     
    I've used just the ordinary (i.e. "high" expansion) screwfix foam to fix insulation vertically before. In our bathroom I over-battened and added cement board & tiles so that was mainly just to help get the boards up and avoid air movement behind.

    However in my garage, for ease of application and because I'm interested in seeing what would happen, I fixed 100mm EPS to the house wall with foam and no mechanical fixings at all. I even foamed 6mm ply onto the EPS as a crude lining - again no fixings. It's still on solid (I can hang off the wall with my hands at the top of the boards, which stop short of the ceiling). I'm not suggesting you do that obviously, but just to reassure that it's a pretty solid fixing.

    If you use high expansion foam, obviously it will expand more, but in my experience using a thin bead for adhesion it expands sideways on the back of the board and doesn't lift it off the surface, providing you've got it properly pressed against the wall (I use plasterboard jacks).
    • CommentAuthorringi
    • CommentTimeAug 11th 2016
     
    With fixing foam you just need to hold the board again the wall for 1 or 2 minutes, as well as putting supports under the board if you wish to leave a gap to foam between the board and the floor.
    •  
      CommentAuthorfostertom
    • CommentTimeAug 12th 2016 edited
     
    Posted By: Dave_07968providing you've got it properly pressed against the wall (I use plasterboard jacks).
    Yes, but that's the onerous snag that 'fixing foam' aims to eliminate.
  16.  
    best way to remove paint from plaster then prior to foaming? Paint is ion good order in most parts, do I really need to be concerned?
    • CommentAuthorJSC
    • CommentTimeAug 12th 2016
     
    No.

    Try a tester if in doubt.

    I'm sure there is an 'engineering term' for this phenomenon, but as an example, If you were to put a suction pad (the ones used for glazing) onto the side of a car, you would be able to, quite easily, rock a 2 or 3 tonne car; all that is connection your suction pad to the body of the car is paint. the paint simply does not "pull" off.

    It is very difficult to rip off a big swathe of paint from a large area.

    Huge swathes of paint simply giving way off a wall doesn't happen (and any kind of insulation board is not really that heavy on a per area basis...)
  17.  
    I thought this was the case, good example!!
  18.  
    Dow Instastik went on fine, boards went up a breeze, should have leveled the one wall prior as slightly out but better than it was originally! Will be interesting to see how my taping and jointing pans out... ;-s

    DO NOT get this stuff on your beard!!
    •  
      CommentAuthorfostertom
    • CommentTimeAug 16th 2016
     
    Posted By: JSCany kind of insulation board is not really that heavy on a per area basis
    In many structural calcs, wind loads dominate - whether inward-pressing or outward-sucking - they can be enormous, far greater than deadweight.
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press