Thorfun

whoops. apologies, the Thermal Conductivity of the 7.3N blocks is 0.19W/mK. still, not bad when compared to a dense concrete block of between 0.7 - 1.3W/mK according to this website https://knowledge.specifiedby.com/blocks-blockwork/

I guess the only downside would be cost as the 80mm PIR is more expensive than a thinner upstand. But as our ceiling height is 2.6m downstairs I need off-cuts anyway.

yes, TF sitting above a basement. The sole plate is sitting on coursing blocks which have a reasonable lamda value 0.11W/mK (https://tarmac.com/products/blocks/toplite-coursing-bricks/#applications) so should help in reducing the thermal bridge. so there’s no ‘issues’ in running the PIR all the below the sole plate? It’s not detrimental in any way? I have already run airtight membrane from basement as a Tony Tray around the block and beam which will join the AVCL on the ground floor which will sit in front of the PIR. another reason for running the PIR all the way down as I can just carry the basement Tony tray straight up.

So if I do need an upstand would if not be easier to just run the internal PIR down to the block and beam? Then I can run the floor insulation to butt up to it?

Yeah, I think I see what you mean but I was planning on adding some insulation externally to cover the sole plate which would mitigate that cold bridge.

Does that mean it has to be dead on accurate though? And I guess I’ll still need an upstand for the outside of the screed?

I guess the other option is to do the UFH and screed before we install the PIR? but then we'd need an upstand of insulation around the screed anyway so by running the PIR to the block and beam means we won't need to do the insulated upstand?

we're getting ready to fit the 80mm PIR internally to our timber frame stud work and I'm wondering how far down it should go? does it just go to the sole plate or can I just take it all the way down to the block and beam flooring? Here's a drawing from the architect and that shows it only going to the top of the slab which is the bottom of the sole plate. but doesn't this assume that the ufh and screed is already in place? as we haven't done the screed or ufh yet and the block and beam is still where the level is at can I simply take it all the way down to the B&B? e.g. and then simply run some DPM on top of the insulation under the screed and up the wall to protect the PIR from the screed? ps. I know the drawing shows hollow core planks, that what was originally planned but we changed it to B&B.

yep, although there are many other subjects that can/will cause sleepless nights. just put my tools down for the next 2 days. will be back on it again Monday!

ahhhh...buggrit. I've just ordered the Intello Plus from Latzel and will send the Protect VC back. I'm 99.999% sure I've done the right thing! And as @SuperJohnG said it's a small percentage of the overall build cost and not much uplift over the Protect membrane when ordered from Germany. so no more sleepless nights for me on this subject I hope! ?

so, I've run the numbers and using the reflective membrane it looks like my U-value will go from 0.129W/m2K to 0.125W/m2K. so even though it does make a difference I'm wondering if that U-value reduction is as important as the benefit the Intello gives with the variable vapour permeability?

I agree about happy to spend the money, I mean, the VC Foil Ultra isn't cheap either! the techno-blurb on the ProClima website certainly sells the product well in allowing moisture in to the house in the summer to aid in the drying of the structure but how much of that is really required in a normal house? how much is marketing BS? these are the questions I just don't know the answer to. quotes like this from the ProClima website worry me as we have 2 green roofs: "The variability of the diffusion resistance of the high-performance INTELLO systems guarantees impressive protection against structural damage, even on demanding structures that are impermeable to diffusion to the outside such as steep roofs with sheet metal covering, roof linings with asphalt roof membranes, flat roofs and green roofs. " so are my green roofs going to rot and collapse if I use the Protect membrane and not the Intello? I doubt it but the evil marketing departments seem to love to tell you that bad stuff is going to happen if you don't buy and use their products!

the timber frame company used the Protect Floor cassette membrane for our Tony Trays (https://glidevaleprotect.com/product/protect-fcm-750-vapour-open-air-barrier/). I've read your posts and blogs about your Barriair installation and it looks great and I've learnt a lot from that reading. that was a while ago now though so I think a revisit on that blog is required to refresh the old grey matter. I was thinking the reflective membrane might yield slightly better U-values than the Intello Plus but wonder/question the benefit of the variable vapour permeability of the Intello Plus. From my understanding it allows moisture back in to the building in the summer (I might be talking rubbish as usual here btw) but I don't see the benefit of that especially as our MVHR system has an enthalpy exchanger so will increase the humidity in the house if required.

I've recently purchased some Protect VC Foil Ultra as my AVCL but am having a bit of a wobble and wondering if I should've gone for the Pro Clima Intello Plus instead! Anyone been through the same dilemma and would care to share their experiences and decision making process? Generally in life the more you pay for something the better it is (not always the way though) so my latest wobble is should I have gone for the really expensive stuff. I'm sure the Protect membrane is great but it seems that a lot of people are using the Intello Plus now so there must be a reason for it.

another Ubiquiti user here. ?

before self-building we bought a new build and our garden turf was laid directly on builders rubble and clay. it was shocking and sank in places. neighbours had the same issue and they complained and eventually got them to put topsoil down and turf it again. we couldn't be bothered in the end as we were selling up to self-build. but as has been said above there will definitely be resistance from the builder but stick to your guns and get the topsoil put down. good luck

even though I haven't ordered our cladding yet I have had quotes and believe that my chosen supplier will be Permachar (https://permachar.co.uk/product/charred-timber-cladding-deep-char/). I'll be looking to order early in the new year. But the shadow gap profile is pretty standard with most timber cladding suppliers tbh so if you have a cladding supplier of choice then they'll probably do it. I'm also sure you can get the profiles with extra grooves but I don't think Permachar do that. but there are many other suppliers that might!

I think that's exactly what I wanted to hear and probably what I'll end up doing! not sure about buying from Europe though as I'll have to pay upfront. if I buy from Jewsons and put it on my account and then pay that off on the credit card I can push the credit to about 3 months! that's worth quite a lot to me as I juggle funds.

Hi all, getting ready to put the PIR internal to the timber frame. When I had a condensation analysis done and spoke to Isover they recommended just taping the PIR to form the airtight layer. but I am worried it won't be enough and also worried of off-gassing and think it might be better to keep the PIR and it's off-gassing behind a silver AVCL membrane (like Protect VC Foil Ultra) instead. Was just wondering what other peoples opinions are on this? is off-gassing really something to be concerned about from a health perspective and would sealing it behind an AVCL stop any of the potentially harmful off-gassing?

if you're going to make changes like that I presume you'd need to go back to planning for a minor amendment. if so, may I suggest something? you seem to be in a very similar situation to us. we bought a bungalow that came with outline planning permission for a 1 1/2 storey house and full planning permission for a bungalow. we didn't want to build either but knew that planning were willing to allow a replacement building. So we got our own plans drawn up for the house we wanted to build and submitted a new planning application which also allowed us to live in the bungalow while building the house and then it demolish afterwards. it seems to me that you're willing to design things around these plans to fit in with what you want but the whole point of self-building is to build exactly what you want and not what someone else got planning for. I would seriously have a good think about starting a new application with a design that you want. yes, there'll be more professional fees involved but, unless it's a build and sell job and not a forever home, you might be thinking 'if only we did it this way'. just a thought.

price? GSHP inside units are big so need a bigger plant room?

welcome! looks like a wonderful project and I look forward to following your progress. one thing I'd say is does changing the existing bungalow in to a garage affect your zero rated VAT status? might be worth double checking with those on here that know more about VAT claims or HMRC themselves? good luck with it all

we have a new 3 phase connection (it was about £20 more for 3-phase so was a no-brainer really) but the whole house will be run on a single phase so we are having a single phase inverter for our 10.5kWp array. just seemed to make sense to me.

this is a pertinent subject for me as our windows are going in next week and I was going to ensure the breathable membrane was correct this week. Are you saying that the breathable membrane should stop before the windows rather than carry it on past the windows?

thanks. it's a GoPro.