Hastings

Do you mean that this layout avoids the usual regulations? I think the rule is no more than 50% of floor area (and no more than 20sqm in total if I remember correctly). Unless coated in fire retarder.

Can anyone make an informed guess at what is being used for the internal wall and ceilings finish in the COP26 house? The pictures show an effect of horizontal 'v' boarding but surely it isn't all timber painted with fired retardant white paint? Would really like to know if there is a new timber alternative to plasterboard allowed in buildings. https://circularecology.com/news/low-embodied-carbon-house-designed-with-circular-economy-principles

I think the plasticiser often used in PVC reacts with polystyrene over time. There are reports of electrical wiring in contact with it having the insulation sheathing 'melt' away after drawing out the plasticiser from the wire's PVC insulation. A tape might have the same effect on polystyrene.

If only things were that logical in practice. Someone on here reported their tests being refused on the grounds of not including a recent calibration of meter certificate.

Except for calibration of, without which BCO may refuse report?

Anyone come across PEATA (Professional Extraction Airflow Testers Alliance) here? For £80/yr and 1 hr online training - it's not clear if there is another charge for this - you become a qualified tester/commissioner and get one free meter hire.

Thank you @ProDave I just received this from my BCO: "Building Standard surveyors are not registered to sign off Hetas registered installations. Please submit an installation certificate" Not clear if that means I can only have it done by a HETAS contractor? Nearest HETAS person is a long way and would need overnight expenses and a lot of mileage costs etc. Some people say that in Scotland you can self install a wood stove and BC will sign it off if it complies. Does it just depend on which council area your are in? They each make up their own rules? Can BCOs keep insisting on additional installation certificates, not included in the warrant, for various things in addition to the gas and electrics? It's adding £1000s I hadn't budgeted for and I don't know where it will end.

Great topic full of very useful info. Reviving it due to specific Scotland requirements. @ProDave @Crofter Did you need to get HETAS certificates for completion/sign-off with BC?

Totally agree. Why private houses have to be built for public use is baffling.

Be aware that the regulations are designed and applied to the house not just to suit the first or current owner. I found this out the hard way when, after getting through planning and getting a building warrant to start work I was informed by Public Health that even though I had no baths or flushing toilets in the property I would still need to be able to provide enough water (no mains is available) for 150L/day per person (=900L/day for my 3 bedrooms) "in case a future owner wanted them installed." So my rainwater storage system plan was ditched - it needed to be so large it would have cost almost the same or possibly even more than a borehole (my only other option). Another blow to the poor old environment.

I must be being stupid, but could you confirm that you really mean use 600 wide stuff for 400 joist centres? Only, the gap between the posi joists chords is only 300. Never used it before but it seems like squeezing 600 stuff into a 300 gap would be hard and would also reduce the effect of it due to too much compression? I am about to insulate mine and I had planned to use 100mm thick acoustic roll and use the ready cut 400 widths to push up there (and not bother getting inside the joist voids too much). Is that a bad way to go? Thanks.

My understanding is that this might not be ok because standard wallboard like Gyproc wallboard even at 15mm is only 9.8kg/m3 according to British-Gypsum's data sheet for it. The Scottish Building Standards minimum is 10kg/m3 - eg. 12.5mm Gyproc Soundbloc or Wallboard Ten. Please correct me if I am wrong - it will save me loads of money.

This might be England regs? In Scotland it is different and the exemption stated is: So, unless I have missed something, you need to waste some money and speed up wrecking of the planet upgrading walls with doors in them too.

Not me, did you mean someone else?

I have been told by my BCO "installation and commissioning certificate is required" because it is "an integral component of your dwelling". When asked what qualifications of a suitable contractor I would need to hire for a valid certificate there was no relevant answer other than recommending an HVAC installer 4hrs travel time away from me. I will be going the self-certification route at completion next year. I won't ask for approval beforehand. (I am an expert in airflow after several decades professional experience in close up bird flight photography :) Could some kind person please point me to info on hiring/buying meter like a Testo 405i to take the measurements?

@HilldesI'm just going by the official Posi installation pdf from their website that I used to install mine. Yours might well have different specs and method etc.

Isn't there a section of 2x4 strongback missing in the last photo? All the joists should be cross-connected to each other I think?

Did you find out about this? I hadn't come across it and am about to start my MVHR installation. Had been worrying a bit whether burying the ducting under the loft insulation was going to be very effective, especially as it has to cross over some of the roof trusses. Was planning to lay 100mm insulation first, then the ducts, then 200mm more and hope the ducting doesn't prevent the insulation from fitting together snugly.

There is Pavatex/Pavaflex wood fibre insulation. Made in the same factory as Steicoflex. Both are breathable and wick moisture so check your design doesn't rely on that. They are generally used in combo with a techno VCL or none at all too. PIR if you use it best fitted with Gapotape otherwise is unlikely to insulate very well.

For 'O2' in my earlier post, read 'oxygen'. O2 is wrong I think. I've been too brainwashed by big corporations!

To be precise, there is a requirement for the alarm to be able to be disarmed permanently.

Fresh air is about 20% oxygen, a tiny fraction of a percent is CO2. It takes days in a sealed room for O2 levels to get low enough to affect you badly but rises in CO2, even though very small, affect us quite quickly. I think that's why there's little interest in measuring O2 levels - it's very hard to run short of it simply from breathing, even in a highly airtight house.

@saveasteading There isn't a requirement for an alarm, only a visible display, of CO2 level. I am fairly sure that is because you cannot normally die in your sleep from high CO2 levels. CO is the cause of that danger as we don't have a natural body alarm for it. A normal healthy person automatically wakes up if O2 and CO2 levels are reaching seriously bad levels. Hence no need for an alarm in every bedroom. I am no expert so please anyone correct me if I am wrong.

Regs state: 3.14.2 Ventilation awareness in dwellings: " CO2 monitoring equipment should be provided in the apartment expected to be the main or principal bedroom in a dwelling where infiltrating air rates are less than 15m3/hr/ m2 @ 50 Pa. " Is it required for a newbuild airtight build with MVHR system, for when there is a power cut?

Thanks but no, I think that refers more specifically to moisture within the actual building materials. This is a bit different.