DannyT

Battens on top of PIR. If you have ever built traditional with dot and dab and taken off a electrical socket, you will feel the draft running behind the plaster board. 100 boards of 25mm 250m2, more than enough for what I need £1500. 150mm dri therm 32, 250m2 £6000 100mm cavity PIR 250m2 £5400 I’ll say it again though. I build houses everyday and there is no way I’d have PIR in the cavity. I’d rather pay the extra and have 150mm fulfill, 25mm PIR internal and batten service void. 1% extra on the whole budget but much better results.

Not worried about the payback period. And for what I get that’s better than the insulation itself is surface I can tape and seal. You can’t get that with plasterboard dabbed onto thermo blocks.

So I’m going a different route because our situation. we purchased with concrete strip foundations already in place and can only go to a max 350mm overall to allow for required bearing on concrete. Having the 150mm full fill with Dritherm 32 but on the inside we are lining the walls and ceilings with 25mm PIR and taped for air tightness with a service void. That should achieve around 0.15. Just the 150mm full fill is a tad over 0.18

Yes. The BBA certificate is for all exposure zones.

I’m a bricklayer. Just had planning approved for south Scotland. Was told rigid boards (PIR) is the standard with 50mm air gap. I sent a email over to building control about having Dritherm 32 fulfill along with the BAA certification. They replied saying I can go ahead with it as long as installed to manufacturers standards. There was no way I would do PIR. Even on my own build taking all the time in the world it would be a nightmare to install. Looks great on a drawing but it just don’t happen in real life and when the bricklayers not getting paid much to take the time you end up with a right mess as shown in photos above. It repels moisture too so won’t get through the cavity, even in exposed locations like mine.

Planning permission has been granted 👍😁

Just to come back to this. The planning officer did want the energy statement at planning stage by a registered assessor to make sure the building will meet criteria before giving it the go ahead. I went ahead and instructed Energy Digest to do the statement, SAP and overheating report. Yes it cost a bit but it’s done now and ready for the building warrant stage. SAP came in at 111 A+ Co2 reductions below.

I’ve contacted a few companies today and prices of around £500 are coming in. quote from planning officer ‘’I am just reaching out at this time to ask if an Energy Statement could be submitted to supplement the plans, please? This is a requirement of all new buildings as per LDP2 Policy OP1, part f). I have attached the template for convenience if that could be filled in, and submitted in due course.” quote from architect “As you will read, he is looking for an Energy Statement in order to process the application further. The statement has to be provided by a registered assessor.” Dumfries and Galloway template that PO sent. It asks for assessors registration number. This indicates to me they want this information at the application stage now. Energy-Statement-template.docx

Our application is in for the new house design. Planning have emailed to say it’s all ready to wrap up apart from requiring a energy statement from a registered assessor. Does anyone have any recommendations? I have most of the figures from the heat loss spread sheet off buildhub but obviously I’m not registered 🙈 Thank you in advance 👍🏻

Anyone interested in 200mm cavity wall ties, some for sale in the market place on here 😉 Ive had to reduce down to a 150mm cavity due to foundations already been in so can’t build any closer to edge of concrete to pass building control. disappointed but I’ll ad 25mm PIR to the inside to gain a little back.

I’m assuming the membrane will be air and vapour permeable to allow vapour out and air in to flow between the gaps in the sarking board? Thats a different membrane to the standard “breathable” type and more than likely expensive. Sorry if gone off topic a bit but just thinking out loud 😁

@JohnMo Thankyou. It’s so hard to find pictures of an install onto sarking and you have provided. Much appreciated👍 That looks very tidy indeed. Is that a swallow/swift box on the gable?

The house is currently going through planning for changes from the original design. In the meantime I’m trying to get my head around the Scottish way of doing a few things. Standard traditional roof construction from what I understand is as follows, Truss Sarking boards Breathable membrane Slate Now if I’m having built in GSE solar trays, my understanding is we will have to do following, Truss Sarking boards Breathable membrane Counter batten Tile batten Slate Is this correct? It’s okay to have the membrane flat with no slack or would membrane go on top of counter batten and be droopy? Trying to create a thin verge without any facia so looking how to achieve this on the gable ends. cheers

NHBC will do random wall plate checks, say every 10th house. Looking for gaps in socks, etc. checking everything structurally before roof gets felted in also. More about just closing off the cavity on a detached house and getting a box ticked. The real fussiness with fire socks/barriers comes when you are on semi detached or apartments and fire needs to be contained to a single unit.