ADLIan

They’re effectively the same product . Other manufacturers also available

In a pitched roof construction insulation between/under rafters = cold roof construction but warm roof space. If all/majority of insulation above the rafter this is a warm roof construction (& warm roof space)

You need to check with Tyvek and their instructions & BBA certificate. This will show required gap any ventilation requirement. Compliance with a bba is deemed to comply with the Regs

MI = manufacturer instruction. Check certification very carefully for use in severe exposure zone and compliance with Regs

Don’t think expanded glass beads are certified or have a history of use in this application.

Slates are quite well sealed and I believe even with a breather type membrane the roof void should be ventilated unless the membrane is certified (BBA or similar) to allow use unvented. construction moisture drying could be part of the problem.

West coast of Ireland + severe exposure + full fill insulation = probably not a good idea. Check MIs, Certification and additional requirements for protection of the wall from wind driven rain (render, tile hanging, rainscreen).

This late in the process solar pv will be the simple, cost effective solution.

The above link references a BBA cert that appears to be no longer valid. The replacement certificate now includes the vent cavity behind the cladding system. Check MIs and 3rd party certificates for exact requirement, accepted good practice is that render should not be applied direct to TF or insulation on TF.

How is eaves to ridge vent provided in that construction?

SAP always includes a heating system, if none specified then default is electric so no need to hide any dedicated outlets.

Approved Docs do cover heat loss from pipes and reference the Domestic Building Services Compliance Guide.

External wall becoming internal? No vertical dpc?

With plasterboard on dab you can add the thermal resistance of the airspace (& dabs) too so will be better than wet plaster. Where wet plaster may offer an advantage is in improving the air tightness of the wall.

Second quality insulation would not be fit for use under the Regs. as it will not comply with the relevant BS, carry CE mark or be BBA approved. Not sure how well this is policed though. Also insulation may be branded as a second for not being the right thickness but more seriously may also have failed other tests such as compressive strength or thermal performance.

Get the insulation manufacturer to do them. They tend to have the correct software and know the conventions that must be used

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)

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!)

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.

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'.

Market forces and latest Appr Doc B has sorted high rise!

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?)

Where in the Building Regs or Approved Docs does it give information on min. roof falls?

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).

Could try Recticel or Extratherm, they don’t appear to be caught up in this mess.