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 But basically both lied about fire performance, used outdated test data, changed the chemistry of products, openly confused the market.....Does not make for good reading.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.

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.

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, .

@oldkettleCheck with manufacturer. Read the certificate very carefully. Does not appear to cover cavity between 2 masonry leaves (a traditional masonry cavity wall detail)

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.

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.

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.

Might not be a common detail but no reason not to insulate in cavity provided 50mm min cavity kept before brick outer.

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.

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.

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.

That’s the issue. Flat roof vs pitched roof, very different design scenarios.

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

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.

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.

3 is very low so don't expect typical contractor to achieve this. Needs very careful design, great workmanship and meticulous attention to detail. The value is not known until tested on completion so if not achieved may need expensive remedial work. If measured the test result cannot be worse than 10. It is possible to avoid the air pressure test on a one-off house but a default air leakage of 15 must be used - probably resulting in a failure under Appr Doc L1A. Also 3 or less means you have to install whole house mech vent.

A&A in liquidation. Now morphed into Insulation South Wales with same owner. Draw your own conclusions. Not sure why anyone would use seconds in a floor (or elsewhere) especially in a self build, life time home. Variation in thickness may give voids in a floor system, made worse if used in multiple layers. What if the reason for being second quality is low compressive strength???? Worth noting also that if second quality product it will not be covered by BBA certificate or comply with Relevant BS.

As mentioned not much detail at moment. New build won't be covered as the scheme is for renovation and upgrading existing housing stock. I doubt DIY will be allowed either as works will probably have to be surveyed & approved by an 'accredited' inspector and then works undertaken by an 'accredited' installer/contractor. All works to PAS 2035 standard?

The SAP rating is based on energy cost. Using an ASHP means electricity is the main fuel. Whilst this is the expensive option it is offset to a degree by the efficiency of the ASHP. The SAP calculation is not very sensitive to elemental U-values so lower U-values will have little effect on the SAP rating. MVHR unless correctly designed (and installed) can actually increase energy use (uses more energy than it saves) and negatively impact SAP rating and Bldg Reg compliance.

The acoustic performance of intermediate floors and partition walls is arrived at by laboratory testing. If you chose not to follow the deemed to satisfy option in AD E then the manufacturer of the floor joist (in this case) should have a lab test & report (see App B of AD E) to prove their system complies with the Regs. The Hickman report does not appear to be to the correct BS. Hickman may have other test reports however in support of the above document.

All Approved Doc E covers detached houses - airborne sound (not impact) in intermediate floors and certain internal partition walls. The standards are not as onerous as those between flats or terraced properties. The AD gives details that are deemed to satisfy the requirements in detached dwellings but only gives suggested construction details for flats & terraced houses (in this latter instance actual compliance must be shown by pre-completion testing or signing up to Robust Details Part E scheme. Intermediate floors in dwellings normally incorporate 100mm of mineral wool quilt with min. density of 10 kg/m3 - note denser will necessarily be better! Some of the engineered joist manufacturers have products/details that omit the mineral wool but follow the MIs to the letter and ask for the test report to prove it.

It is not recommended or accepted good practice to render directly to timber frame or onto insulation on timber frame. Render should be onto a render carrier board with a vented and drained cavity.

The renovation/upgrade of existing floors, walls and roofs is covered by the thermal requirements in Approved Doc L1B (assuming England) which details U-values to be achieved. Building Control do have a degree of flexibility however and exceptions are listed. This type of work however is very badly policed by BCOs, perhaps partly because they're not informed. Lack of proof of Bldg Reg compliance here may affect any future sale of house.

There is normally a vapour control/separating membrane between the insulation and the screed which then inks to the VCL in the wall. If not done then above both seem to be reasonable solutions though a full membrane over the floor may be a bit of overkill.

Is '70' a typo error, should just be '7'? Problem with using the default value of 15 is that it probably results in a failure under Part L1A.