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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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      CommentAuthorSteamyTea
    • CommentTimeMar 29th 2017
     
    Posted By: gravelldBuilders should be engineers really, involved in the appliance of scientific research into building healthy, safe, sustainable dwellings.
    Yes they should be, trouble is that anyone with a toolbox calls themselves and engineer these days.


    Posted By: gyrogearpart of said operations involving sticking their self-identifying bar-code stickers onto each part of structure that they touch...

    so that site inspections would identify who did what...
    That is a brilliant idea, easy and cheap to implement, one sticker on the job, anther on the jobsheet, along with a signature.
    • CommentAuthorgravelld
    • CommentTimeMar 29th 2017
     
    I like it, some sort of NFC tag might be harder wearing and easier to locate though.
  1.  
    I though NFC related to the likelihood of it complying with Bldg Regs....
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 29th 2017
     
    Yes, and anyone that gets 5 bad marks against them has to put their contactless bank card in the wall by the energy meter. Then the owners can just grab 30 quid when they feel like it (as long as they have a card reader).

    Down here, they call contactless payment a Voodoo card, it is magic how it works but not to be trusted :bigsmile:
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      CommentAuthordjh
    • CommentTimeMar 29th 2017 edited
     
    Posted By: mike7Yes, it's Knauf dritherm earthwool, 75mm thick nominally, in a 100mm cavity. so presumably this is intended to be a 'partial fill cavity' , described as one option on the packaging

    Hmm, I'm surprised to learn that it's approved for partial fill. I wouldn't have thought that it has sufficient stiffness to leave a clear cavity. I see that the BBA cert http://www.knaufinsulation.co.uk/sites/knaufuk/files/downloadfile/dritherm_bba_certificate.pdf lists certain specific retaining clips for use in partial fill applications. I wonder if they have been used?

    Knock the wall down and start again would seem to be the sensible option.
    • CommentAuthormike7
    • CommentTimeMar 30th 2017
     
    Posted By: djh
    Posted By: mike7Yes, it's Knauf dritherm earthwool, 75mm thick nominally, in a 100mm cavity. so presumably this is intended to be a 'partial fill cavity' , described as one option on the packaging

    Hmm, I'm surprised to learn that it's approved for partial fill. I wouldn't have thought that it has sufficient stiffness to leave a clear cavity. I see that the BBA cert http://www.knaufinsulation.co.uk/sites/knaufuk/files/downloadfile/dritherm_bba_certificate.pdf lists certain specific retaining clips for use in partial fill applications. I wonder if they have been used?

    Knock the wall down and start again would seem to be the sensible option.


    No such clips seen.The Knauf file above suggests it is ok for partial fill, but the one given below suggests not.


    http://www.knaufinsulation.co.uk/system/files_force/downloadfile/3_1_1-masonry-cavity-walls_1.pdf?download=1

    They quote a tolerance on the cavity gap of 0 to +15mm above the slab thickness, so 85mm thick slabs would just qualify in the case of this 100mm cavity. Whatever, its the lack of close butting of the horizontal joins that is the main problem, made worse if that gap connects with vertical gaps both sides of the insulation.
    • CommentAuthorMarkyP
    • CommentTimeMar 30th 2017
     
    I've used dritherm - good stuff. I think the oversizing of the cavity is to allow for the insulation to expand. I've used dri-therm 32 and it does expand once unpacked a good way beyond it's stated thickness. You'd easily fully fill a 140 -150mm cavity with 125mm thick insulation. I think brickies that have used it before tend to oversize to allow for this, fitting it into a cavity of similar size to the stated thicknes and the expansion combined with inevtiable mortar snots tends to push out the brick/blockwork and they stuggle to keep the wall flat.

    this stuff can be really tightly butted and knits together well. There's really no excuse for those gaps. Even if the ties arent falling quite right you can make a small slit cut in the batt to allow it fit down over the tie to sit tightly on the batt below it.
    • CommentAuthortony
    • CommentTimeMar 30th 2017
     
    http://www.tonyshouse.readinguk.org/icon/house24.JPG

    My cavity was 310 for three of 100 R32 batts
    • CommentAuthorcjard
    • CommentTimeApr 2nd 2017
     
    What made you opt for that particular insulating model, tony?
    • CommentAuthortony
    • CommentTimeApr 2nd 2017 edited
     
    cost :) fibreglass is cheapest bang for your buck in terms of u value. also no possibility of thermal bypass. bricks and blocks work out cheaper than other methods too.

    Mine is pretty much a solid wall with 300mm EWI and a brick rain screen, I used high lime mortar so no damp or wet problems.
    • CommentAuthormike7
    • CommentTimeApr 2nd 2017 edited
     
    Posted By: MarkyPI've used dritherm - good stuff. I think the oversizing of the cavity is to allow for the insulation to expand. I've used dri-therm 32 and it does expand once unpacked a good way beyond it's stated thickness. You'd easily fully fill a 140 -150mm cavity with 125mm thick insulation. I think brickies that have used it before tend to oversize to allow for this, fitting it into a cavity of similar size to the stated thicknes and the expansion combined with inevtiable mortar snots tends to push out the brick/blockwork and they stuggle to keep the wall flat.

    this stuff can be really tightly butted and knits together well. There's really no excuse for those gaps. Even if the ties arent falling quite right you can make a small slit cut in the batt to allow it fit down over the tie to sit tightly on the batt below it.


    Dritherm 32 is the best quality Knauf offer, 37 used in the case I'm looking at. Could be there's more material in yours, MarkyP, more ability to expand, more rigidity in the slab and so less possibility of slumping, which is what seems to have happened to create the air gaps on the horizontal.

    It's clear from their installation notes that 15mm oversize of cavity is to allow for mortar projections from the outer leaf and - I forget the exact term used , but on-site variations, lack of skill, carelessness etc was what they meant. I spoke to a tech adviser at Knauf and sent him the photo. He suggested lifting out the insulation and blowing in insulation as for an existing cavity wall. Sounds laborious, but he assured me it was do-able.
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      CommentAuthorjoe90
    • CommentTimeApr 2nd 2017 edited
     
    Posted By: tonycost :) fibreglass is cheapest bang for your buck in terms of u value. also no possibility of thermal bypass. bricks and blocks work out cheaper than other methods too.

    Mine is pretty much a solid wall with 300mm EWI and a brick rain screen, I used high lime mortar so no damp or wet problems.


    Exactly why I copied Tony in my build.i have to say it's going well and my builders are doing a great job.
    • CommentAuthorwookey
    • CommentTimeApr 5th 2017
     
    I used dritherm32 (100x2) in a 200mm cavity and it works well (when not installed by monkeys). It is just about stiff enough to use for partial fill with clips to hold it to one side, although that's not an option I'd go for.
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