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Products: Semi rigid insulation with a cavity?

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  1.  
    • CommentAuthorMike George
    • CommentTimeMay 19th 2010 edited
     
    I'm looking at a new insulation system for timber frame buildings. Part of the make up will necessitate using insulation between the timber studs. I could use something rigid such as PUR but would prefer to use one of the more 'natural' products. Ideally the conductivity needs to be at least 0.038W/mK [ie as good as thermafleece]

    My question is this:

    Which insulations can be used between timber studs while maintaining a clear 25mm cavity on the warm side? There must be no chance of 'slumping'

    Any help much appreciated
    •  
      CommentAuthorfostertom
    • CommentTimeMay 19th 2010 edited
     
    Icynene.
    You know that any kind of fitted boards, squeezed batts, quilts etc give away so much effective insulation value, to air inflitration
    What's the inboard cavity for? If not for that, then Warmcel is hard to beat, and absolutely needn't slump. To be 100% sure of that, on current project, 'weaving' 1.6mm galv garden wire horizontally, zig-zagging alternately inboard/outboard of the studs, @ 450 vertical c/cs. Gives the Warmcel something to grab onto and not slump. On the same job, eliminating horizontal noggings - the wires achieve inter-stud stability. Where p'b'd or OSB cross-edges need supporting, 0.7mm dryliner's galv flat-strap tacked across the stud face, boards fixed with self-tappers.
    • CommentAuthorMike George
    • CommentTimeMay 19th 2010 edited
     
    Thanks Tom. Do you have a link to any technical literature?

    Posted By: fostertom What's the inboard cavity for?

    I'm bound by confidentiality at the moment sorry.

    The system would hopefully overcome the air infiltration issues. And would require pressure testing anyway.

    The aim is to reach 0.2W/m2K as part of a whole house strategy to hit CSH Level 4 target.
    •  
      CommentAuthorfostertom
    • CommentTimeMay 19th 2010 edited
     
    • CommentAuthorMike George
    • CommentTimeMay 19th 2010 edited
     
    Ingenious solution to the slumping issue, though as you say won't work with an inboard cavity.

    Icynene k = 0.04W/mK so not good enough either:cry: Looks like I'm stuck with something rigid like XPS or PUR.

    I also added more to my post above
    •  
      CommentAuthorfostertom
    • CommentTimeMay 19th 2010 edited
     
    How about studs say 120x50 crossbattened with e.g 70x50s, so 190 thk blown Warmcel or, somehow, sprayed Icynene? Your sheathing cd go in between, so Icynene sprayed from both inside and outside onto it. Foam-in-place Icynene is on the way, in fact another post says it's here already. For roof, multiple purlins instead of rafters, so the 70x50 'cross battens' end up going down-slope, ready for tile battening. I'm relying on the sheathing, gap-filling glued and screwed, all edges supported (incl on flatstraps as above) as the airtight layer - can be completely continuous and uninterrupted, walls to roof.
    • CommentAuthorTimber
    • CommentTimeMay 19th 2010
     
    What about undersizing the studs by 25 mm and then using a slightly wider vertical batten or horizontal battens to retain the fibre insulation (therma fleece, rock or glass wool etc) in place.

    Timber
    • CommentAuthorMike George
    • CommentTimeMay 19th 2010 edited
     
    Posted By: fostertomHow about studs say 120x50 crossbattened with e.g 70x50s, so 190 thk blown Warmcel or, somehow, sprayed Icynene? Your sheathing cd go in between, so Icynene sprayed from both inside and outside onto it. Foam-in-place Icynene is on the way, in fact another post says it's here already. For roof, multiple purlins instead of rafters, so the 70x50 'cross battens' end up going down-slope, ready for tile battening. I'm relying on the sheathing, gap-filling glued and screwed, all edges supported (incl on flatstraps as above) as the airtight layer - can be completely continuous and uninterrupted, walls to roof.


    Posted By: TimberWhat about undersizing the studs by 25 mm and then using a slightly wider vertical batten or horizontal battens to retain the fibre insulation (therma fleece, rock or glass wool etc) in place.

    Timber


    Thanks both, I thought about that but the idea is to give the mass hosing market a system they could readily adapt to without too much difficulty. There is also the question about whether 70mm studs [in place of the usual 95mm] would effect the structural stability of the house.

    Timber, You seem to be involved in timber framing in quite a big way, would you see the thinner studs as a problem? [from both a supply and install point of view]
    • CommentAuthorevan
    • CommentTimeMay 19th 2010
     
    I would have said Hemcrete - slump proof, perfect for ensuring a good seal between battens, can be poured in from a site mixer.. but the thermal conductivity only goes down to about .05.
    • CommentAuthorTimber
    • CommentTimeMay 19th 2010
     
    Mike - Indeed I am!

    What other insulation are you looking to install within or outboard of the wall. I ask this as 70 mm and even 95 mm of 0.038 W/mK insulation would not be sufficient to hit 0.2 W/mK. I guess you are installing some external insulation to hit the required level.

    70 mm studs would be OK, as long as they are strong enough to support the imposed load of the structure, and only a structural engineer can answer that on a project specific bassis or a worst case scenario.

    The most typical timber section for external walls is 140x38 mm CLS C16 softwood. The main reason for this is insulation values. Up until 2006/07 89x38 mm studs were the norm, but you can use any section you want so long as you can get the required structural performance.

    I imagine you are leaving the 25 mm internally for service installation.

    Are these to be kits or volumetric units (or can't you say)?

    Timber
    •  
      CommentAuthorfostertom
    • CommentTimeMay 19th 2010
     
    Posted By: Mike Georgeto give the mass hosing market a system they could readily adapt to without too much difficulty
    Trying to save them from facing up to thicker walls?
    Posted By: Mike Georgemass hosing market
    There's a joke in there somewhere
    • CommentAuthorstephendv
    • CommentTimeMay 19th 2010
     
    Posted By: Mike George
    Which insulations can be used between timber studs while maintaining a clear 25mm cavity on the warm side? There must be no chance of 'slumping'


    Use OSB directly against the insulation and studs (no cavity), so that you can use it as the airtightness layer and tape up all the seams. Then use battens to create the 25mm cavity between OSB and plasterboard, so that you can happily install services without touching the airtightness layer.
    • CommentAuthorCWatters
    • CommentTimeMay 19th 2010
     
    Some of these are semi rigid (Isonat and Homatherm I think)..

    Warmcell (cellulose fibre) = 0.040W/mK
    http://www.naturalinsulations.co.uk/index.php?location=Warmcel

    Isonat (55% wood fibre, 30% hemp and 15% polyester) = 0.038 W/mK
    http://www.naturalinsulations.co.uk/index.php?location=Isonat

    Thermafleece (Sheeps wool) = 0.039W/mK
    http://www.naturalinsulations.co.uk/index.php?location=Thermafleece

    Thermafleece PB20 (Sheeps wool and polyester) = 0.039W/mK
    http://www.naturalinsulations.co.uk/index.php?location=PB20

    YBS Non-Itch Eco Fibre (recycled plastic bottles) = 0.039 to 0.0425 W/mK
    http://www.just-insulation.com/eco-friendly_ybs_non-itch_insulation_general_purpose_cavity_slabs_from_ybs.html

    Homatherm (wood fibre) = 0.040 W/mK
    http://www.einfachunschlagbar.de/
    • CommentAuthorTimber
    • CommentTimeMay 19th 2010
     
    Another question Mike, can you afford the insulation bulging into the 25 mm void? I ask because any kind of fibre insulation will be very hard to install such that it doesn't belly out into the void, or is well overcompressed at the edges.

    Timber
    • CommentAuthorMike George
    • CommentTimeMay 19th 2010 edited
     
    Posted By: TimberMike - Indeed I am!

    What other insulation are you looking to install within or outboard of the wall. I ask this as 70 mm and even 95 mm of 0.038 W/mK insulation would not be sufficient to hit 0.2 W/mK. I guess you are installing some external insulation to hit the required level.

    Timber


    There will be other insulation, yes.

    Posted By: Timber

    The most typical timber section for external walls is 140x38 mm CLS C16 softwood. The main reason for this is insulation values. Up until 2006/07 89x38 mm studs were the norm, but you can use any section you want so long as you can get the required structural performance.

    Timber
    Can I ask what u-value you get down to with this construction?

    Posted By: TimberMike -
    I imagine you are leaving the 25 mm internally for service installation.

    Are these to be kits or volumetric units (or can't you say)?

    Timber


    Back to the ties of confidentiality there I'm afraid.

    Posted By: fostertom
    Posted By: Mike Georgeto give the mass hosing market a system they could readily adapt to without too much difficulty
    Trying to save them from facing up to thicker walls?
    Yes


    Posted By: fostertom
    Posted By: Mike Georgemass hosing market
    There's a joke in there somewhere


    Well it made me laugh anyway.

    Posted By: TimberAnother question Mike, can you afford the insulation bulging into the 25 mm void? I ask because any kind of fibre insulation will be very hard to install such that it doesn't belly out into the void, or is well overcompressed at the edges.

    Timber


    No, can't afford bulging. Though I think I have found a solution to that [thanks to Tom's woven mesh idea] - two part stud with something like strawberry netting holding the insulation in place.
  16.  
    Posted By: stephendv
    Posted By: Mike George
    Which insulations can be used between timber studs while maintaining a clear 25mm cavity on the warm side? There must be no chance of 'slumping'


    Use OSB directly against the insulation and studs (no cavity), so that you can use it as the airtightness layer and tape up all the seams. Then use battens to create the 25mm cavity between OSB and plasterboard, so that you can happily install services without touching the airtightness layer.


    Thanks for the idea but the cavity is essential.
  17.  
    Thanks also to Colin. Some good links there and the Isonat is a real possibity as it hits the k-value target I need.
  18.  
    Found these to be denser than your average batt
    http://www.insulationexpress.co.uk/Cavity-Wall-Insulation/Knauf-Dritherm-Cavity-Slab-32-Ultimate.htm
    not on the eco top ten list , but made from waste glass, i think
  19.  
    Excellent, thanks James
    •  
      CommentAuthorali.gill
    • CommentTimeMay 20th 2010
     
    my thoughts were 2-part stud - especially having seen how warmcel is applied. possibly then followed by an acoustic batten to create the 25mm cavity and achieve part e and other related noise issues for social housing.

    alternatively you could just use a 25x25mm batten on the side of the stud to retain a scrim cloth and pump warmcel through a few holes in it, though it would tend to bulge out if too much is pumped in - but it might help if you need extra fixing surface for the phantom 25mm 'secret bit'.
    personally my bet is that it is some form of heated wall panel.
  21.  
    close but no cigar:smoking:
  22.  
    The Rockwool batts that we use for External Insulation have a good density and won't slump http://www1.rockwool.co.uk/graphics/RW-GB-implementation/brochures/Walls_of_Fame.pdf
    They may be another option!
    • CommentAuthorSaint
    • CommentTimeMay 22nd 2010
     
    MIke, even the most ardent timber frame guys are starting to look at SIPs now either as infill panels or cladding.
    Airtightness, excellent U values, speed of construction etc. etc. The devil is in the detailing as usual
  24.  
    ''Posted By: Mike George
    mass hosing market

    There's a joke in there somewhere''

    I think the Pope controls it.

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