Nickfromwales

If cold air cannot get into the void, then delta T and interstitial temp differences diminish massively. Also helps that the blown-in cellulose slumps back under its own weight so is not in true full contact with the underside of the OSB. The residual air gap is stagnant, and the humidity therefore controlled to a point that this is just non-problematic. I'd prefer this option vs a hybrid, as you have to be very conscientious (there, I spelt the bastard right this time lol) going down any other routes. Critics will choose safety in the face of fear, as in they doubt themselves and take the safe way out.

Oh bollocks......not enough sleep happening atm lol. Consciencous / conscientious. LOL....................................we're both shite at this haha

But not as big a bonus as "reverse VAT" on a LOT of things, meaning you don't pay the VAT in the first place, and therefore you don't have to go out of pocket from the get-go and wait until the end of the build to get it back

Architectural technicians are usually less pretentious and much better value for money. I take it you know you’ll be zero VAT rated for a replicant dwelling also? Start asking questions and searching the forum, fail to prepare - prepare to fail. Much better, and far less stressful, to understand the problem and resolve it before hand vs on the fly when the money clock is ticking

You can go for a hybrid roof there also, but the execution needs to be flawless. Needs a VERY contentious installer.

All I can say is it was the 5m x 5m ish balcony, and then a strip running off that about 1.5m wide x 7.5m long, basically a flag shape section of flat roof. No ventilation, MBC PH TF, and currently been weathertight, insulated (fully pumped with cellulose), and dry for prob 3-4 years, been lived in for 6 months and zero issues.

You are mistaken. These issues probably happened AFTER you took out the insurance. I am sure you just have very bad memory......

I've just moved clients into an MBC TF (PH) that had this exact detail, and the GF flat roof ran between the 2 separated upper floors (house had two staircases) and extended out into a 5m x 5m balcony. No issues there and I have been on site there on/off for a few years, including being up in the cellulose looking for a lost MVHR connection (that was just a delight....). I am finding out, at a saddening rate of knots, that the types of people in the industry I used to look up to are well educated f*ckwits. I've only met 2 or 3 architects over the last decade who have impressed me, others I have recommended the clients dismiss (and go with the one I rated). It's shocking how the public are left to rely on such people to help them and trouble-shoot, even at the design stage (pre-construction) but are just useless on a good day, expensive to the point of destruction on the bad days....

No need to spit on it, just sand gently and paint 🤣 It's Saturday night ffs, and if anyone's posting here whilst sober I want their name, rank and number so they can get a proper bollocking.

That should read "tape & joint" aka dry-lined, as that doesn't have a wet plaster coat. Dot & dab is how the boards are affixed to the underlaying wall and taped and filled joints are the ones always visible forever aka 'shart'. I can recommend a fantastic plasterer in the Coventry and surrounding areas (he'll drive an hour or so). PM me for details.

Yes. Can you get a spirit level or other straight edge and see if the top of the window frame is deflecting downwards (bends down near the crack)? Best to ask a fitter to find out why the window cracked when they call out to remove the glass to survey it for size and type (they'll have to do this to order the replacement anyways).

I am suggesting you double-barrel the ASHP's at the same location, with the same plumbing, to keep cost and impact down (referred to as cascading). You simply do not have enough kW of 'oomph' to keep up with the fabric and ventilation heat loss at the new, significantly lower flow temp.

Do you know the installation methodology of the UFH and thickness of insulation? If the system is otherwise working A-OK, does it still not then get to 21o?

I think you need a new SE tbh. I doubt they have much experience with this type of arrangement unfortunately. This Larson setup is a-la MBC TF, have you seen their website for examples of how this is achieved? My current clients build is with MBC and has a brick plinth, and the outer skin of the truss sits atop the EPS so no cold bridge. The EPS footing blocks come with an extension, to provide a concrete strip for the brickwork to sit on.

Have you seen concrete screws? They go through the timbers and straight into the concrete floor. Drill with a 6mm sds pilot, clear the hole a good few times to remove debris. Drill at least 3/4 of an inch deeper than you need. https://www.screwfix.com/p/easydrive-tx-countersunk-concrete-screws-7-5mm-x-70mm-100-pack/9643h?ref=SFAppShare

Yup. The liquid will get through, then lift the trays. Just gas nail pipe clips down maybe? That’s over solid concrete, 22mm gas nails into the strips. Was very quick going down tbh

@london8 Is this the only form of space heating in the house? Does it not have central heating? I think you’d be better off with a pair of oil filled radiators which have a bit of smoother output vs just on/off like halogen / ceramic or radiant heating does. To answer your specific question I do not know of one. @SteamyTea linked above to the nearest thing to what you have asked for I think. 3000w running constant is going to be very expensive to run though.

Is the pipe sealed well with a good external grade mastic? Also, note the brick vent set into the wall, another possible cause or point where rainwater may be getting driven in. Water / damp does very mysterious things, unfortunately, but could you confirm if this is a solid brick wall without cavity? The air brick makes me wonder, or is that from an extractor fan / other?

Feck or bollocks is fine. Let it all out. Id recommend putting a good quality lining paper on first, as oil based stuff hates taking emulsion. Wallpapering would hide these sins far more robustly.

This is the only way I’d ever install a system for a domestic client. One previous had a huge garden and were almost a small holding, chickens / veg gardens etc, and when the ground-workers were there with a 15T machine I suggested that if they did want to do RWH they should install 2x 5000L tanks whilst cheap (cost-effective) to do so, exactly for the reason of not ever running dry or as near to as dammit. More solar PV went on instead 👌. I said it’s pointless going for anything smaller as it’ll not pay back over time, but sadly there are some great salespeople about….do your own maths people!

I’ve used Compacfoam under the doors and sliders, on a previous job (where I had to removed poorly installed units and refit after the installers made a piss-poor job of it all and disappeared). Very good stuff, just need to see here exactly where the cold bridges exists and how deep the product needs to be to created some separation.

Yup, I think mostly aimed at / suitable for more adverse installs, particularly where freezing is going to be a known issue.

To do this properly, the idiot you called out should have purged every loop with cold mains water (to blast the air out). The problem you face is, the pump will move water through the UFH pipes at a snail pace, so if all the loops are open you can divide the pump power by the number of loops. You need 100% of the pump on each loop individually to stand a chance, hence my advice. Best I can offer at 00:25, but I’ve got 4 kids and I don’t want to see you or them freezing your rear ends off. Go see the ‘technician’ that called out to ‘help’ and kick him in the testicles. Twice. As much use as a kickstart on a submarine.

Each loop needs to be on for 20 mins to bleed itself, this assumes the automatic air vent is open. You start with all other loops off, actuators all removed, and then bleed 1 loop at a time.

So, I think you are now airlocked throughout. Quick hack; take every actuator off except loop 1 (you choose), and then run the system. Wait for 20 mins to bleed out the trapped air, then open loop 2, and so on. Most advice I can give you tonight I'm afraid. Genius. Useless w8nker I hope you've not paid for this disservice?!?