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ADLIan

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Everything posted by ADLIan

  1. ADLIan
    Get the insulation manufacturer to do them. They tend to have the correct software and know the conventions that must be used
  2. ADLIan
    Re U value. Thermal bridge in layer 5 at 15% timber will have a big impact. Resistance of 25mm airspace is wrong, should only be 0.18 (not 1.02)
  3. ADLIan
    This is the problem with any injected cavity wall insulation - the tolerance on installed density and the crude method used to asses the adequacy of fill means it is impossible to be sure there are no voids. Only solution would be a thermographic survey (or build the insulation in so you can see any missing pieces!)
  4. ADLIan
    The U-value of tapered roofs may be based on the maximum U-value/minimum thickness (subject to back stop values in Approved Docs L & C) or the 'average' thickness for the desired U-value. With most tapered systems the U-value is not the simple arithmetic average, the calculation method is in BS EN 6946 and involves splitting the roof down to various set shapes. This is probably a job for the system designer.
  5. ADLIan
    LABC issued certificates for both Celotex & Kingspan after both manufactures approached their local building control office in West Suffolk & Hereford. Kingspan swamped the BCB at Hereford with fire test data and it does not appear that they were experienced or qualified to make a judgement - K15 certainly should not have been classed as ' limited combustibility'.
  6. ADLIan
    Market forces and latest Appr Doc B has sorted high rise!
  7. ADLIan
    The problem with both kingspan and celotex and fire goes back to 2008 when new European/British manufacturing standards were introduced with new fire tests (BS EN 13501-1). If they had adopted these tests their products would have been classed as ‘combustible’ and they would have lost a lot of business. Instead they hid behind the old BS 476, Parts 6 & 7, tests which are simply not relevant to the pur manufacturing Standard. PUR/PIR and phenolic foams will be classed as combustible but may fall into slightly different Euroclass categories (C or D?)
  8. ADLIan
    Where in the Building Regs or Approved Docs does it give information on min. roof falls?
  9. ADLIan
    BS 6229 states design fall should be 1:40 to make sure actual fall is no worse than 1:80 accounting for site tolerances & inaccuracies. There are some waterproofing systems designed for zero falls - these should have 3rd party certification and need careful design (no back falls).
  10. ADLIan
    Could try Recticel or Extratherm, they don’t appear to be caught up in this mess.
  11. ADLIan
    We may drift off topic here. But basically both lied about fire performance, used outdated test data, changed the chemistry of products, openly confused the market.....Does not make for good reading. Celotex also admitted overstating thermal performance just after the Grenfell fire. Yes, other manufacturers are available.
  12. ADLIan
    For a new extension wall you need 0.28 W/m2K. For new build house it depends upon the numbers that come out of the SAP assessment, looking at better than 0.25, ideally better than 0.20. After the revelations at the Grenfell Inquiry this week not sure why anyone would consider Celotex or Kingspan.
  13. ADLIan
    That one looks to be more relevant. Your bco will have to decide if kiwa certificate is acceptable. Kiwa cert looks to be very much desk top study based. BBA have full size test rigs to make sure cavity gets fully filled and system will resist rainwater penetration - not sure if kiwa do this, .
  14. ADLIan
    @oldkettleCheck with manufacturer. Read the certificate very carefully. Does not appear to cover cavity between 2 masonry leaves (a traditional masonry cavity wall detail)
  15. ADLIan
    Awhile since I was involved in consultation on RHI. It was originally planned for upgrading heating systems in existing housing and tied in to certain fabric upgrades. Not sure why self builders were given exemption, as you state with a well insulated modern build payment is minimal.
  16. ADLIan
    There is a table in L1A that mentions 0.18 in walls but this figure is not cast in stone. Possible to still get compliance with a wall at 0.25(ish). SAP gives a lot of design flexibility.
  17. ADLIan
    Very little insulation in a 1980s timber frame house so condensation risk very different from current standards. From memory issue in 1980s was bad building practice and poor detailing leading to moisture penetration and subsequent rot, may also have been issues with fire performance. Also remember reports of media overhyping the issue of only a few actual problems - didn’t help Barrats though. Current timber frame construction is a world away from back then.
  18. ADLIan
    Might not be a common detail but no reason not to insulate in cavity provided 50mm min cavity kept before brick outer.
  19. ADLIan
    Prestige Devs deal with park homes. Requirements here very different to ‘normal’ houses having to comply with Building Regs so the linked diag may not be relevant.
  20. ADLIan
    BCO is probably concerned with timber cladding externally and proximity to the boundary. Can just about guarantee you will not find a test ‘certificate’. As above there are so many materials and possible combinations of materials. I’m pretty sure that a timber stud wall with plasterboard one side, insulation and then osb externally will give 30 mins. fire resistance. The multipro in place of osb should give at least the same performance. Doubt you’ll find the test certificate though.
  21. ADLIan
    You need to check what part of ‘fire regulation’ your BCO is referring to. The A1 rating refers to a materials reaction to fire, this is a test on the martial alone. If looking at the whole wall it is the resistance to fire that may be required depending upon application (load bearing or not, fire from one side or both sides.......). As mentioned there are so many possible combinations of materials they won’t all be tested! As a sheathing alone the multipro will be better than osb.
  22. ADLIan
    That’s the issue. Flat roof vs pitched roof, very different design scenarios.
  23. ADLIan
    Default is to use 15% bridging of the insulation in timber frame - manufacturers will take this into account in their U-values. 90mm Celotex in the above wall will achieve approx 0.35 W/m2K. adding a further layer of say 25mm internally would drop this to approx 0.24 W/m2K
  24. ADLIan
    Asking for trouble with that build-up I'm afraid and I doubt that you get any insulation manufacturer to stand by it. There was a 'rule of thumb' of 2/3 of the thermal resistance above the deck, max 1/3 below but it was a rule of thumb and not backed up in any British Standard. BSs on condensation and flat roofing would warn against a 'hybrid' flat roof.
  25. ADLIan
    The Building Reg Appr Doc gives details for performance/spec of stainless steel wall ties, listing relevant BSs. I don't think the Standard covers other types of wall tie so BBA or equivalent would be needed to show fitness for use. The performance requirement for rebar is very different to that required for wall ties as they are totally different applications.
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