Iceverge

I did a bit of reading. It's apparently very sensitive to getting the slump exactly correct. Small variations of temp can make it difficult to work. Also because it's so runny you need to hermetically seal the EPS or you'll have leaks of watery cement paste and it'll make the concrete crumbly. Normal concrete seems a better fit.

I don't think the caution urged is anything against the SCC. More so DIYing an insulated slab without an experienced crew. I've never used it but it sounds ideal for pouring inside rising walls as a subfloor for example.

From my understanding the applied fools don't last as long. Ligter colours suffer less thermal exoasuand contraction too.

Different profiles and hard ware and quality of assembly make a big difference.

Not exactly. Its more important to ensure no direct air paths through the structure (airtightness) and avoiding interstatial condensation by stacking layers of low permeability materials. In your initial suggestions it was a recipie for trouble with VCL, layers of foil faced PIR, OSB and steel. Wait what's that noise......gold clubs being thrust into the back of a BMW x3.......... Ray bans and newly whitened teeth shining from behind the wheel......... It's the Kingspan salesman off on another holiday. He's on the midday jet2 from EastMids to Faro. He'll be on the course for a quick 9 before sunset. "Thanks again Architect for being too lazy to do any due diligence on my helpful book of detail I left on your desk" he'll say raising a glass of sparkling rose in salute.

There's no easy life with concrete and it takes skill to get it right. As much as plastering a wall in my view. Can you access good contractors for it, it's a real mess when it goes wrong as @Gone West can attest to?

I feel a 40 page bin location design statement AI written coming on. Either that or go on the planning portal and copy and paste someone else's.

U Balkus only takes a static shot of the situation at one temperature. -5 outside (you can change this). Unless you live in Baffin Island this weather is unlightly. If you raise the external temperature to something positive you'll see the condensation risk disappears. As long as you don't have to raise it too high, say much above 7 to 8 deg your wall will be drying for more of the year than wetting and it'll be fine. Remember diffusion is only a tiny part of how water makes it way into the wall. Air leaks through bad airtightness are far more significant. Pay attention to external driven rain on old buildings too. Something like a Auto Brick oil will repel water without compromising the walls ability to dry out.

What they really mean is we don't want to have a house that looks like this,(because there may be poor people inside). What a bunch of snobs they are. White uPvc looks just fine if appropriate care is taken of the proportions of the windows. It's amazingly durable if you get good stuff. I don't know what the aluminum adds really. That's ours below. White T+T Veka Softline 82. White uPvc fascia and soffit and black guttering and down pipes whilst we're at it.

I assumed there was no mains electric but a £10 fan heater would be fine if there was. I have a 2m mini office. Good airtightness, 0.23W/m²K walls and 1W/m² 2G doors and a 3G window. dMEV. Average U value of 0.35W/m²K. Once it's up to temp a couple of hundred Watts keeps it cosy.

A hut probably has a surface area of 30m². Assume it has 50mm of PIR it will end up with an average U value of 1 W/m²K including bridging and windows. At -5 it will need 750w. The smallest timber stove is about 4kW so you'll quickly overheat. A campervan type diesel heater would be more comfortable.

Or a cheapo dMEV fan with humidistat if MVHR isn't in budget or feasible.

Good on you for doing the sums. They're the only place which hides the truth, forget payback times like @JohnMo says. Think thermal comfort. Once you get anywhere near Bregs airtightness and thermal bridging become massively more important than U values. Detailed excellently a 0.3 U value house would be very nice to live in. As for the windows why not PVC? https://sbwgroup.co.uk/products/veka-softline-82-md/ These are the same as ours (Different installer).They've been excellent. €16k inc VAT for 32m² of glazing in 2020. Gealan, kommerling, rehau and Internorm all do high quality units.im sure there's more, just avoid the cheap crap.

Interesting study that. Undoubtedly there's marked humidity buffering effect with the hygroscopic materials. The test was done in the presence of controlled mechanical ventilation. Had this been turned off I suspect RH would have climbed higher than desirable in both cases. Passively/manually ventilating can work with the proviso you have one of the following. 1. Heat driven stack effect. 2. Very large internal volumes. 3. Diligent occupants. Hygroscopic materials will undoubtedly help smooth out the worst RH extremes with the latter two. However for almost all owners I would think mechanical ventilation would still provide much cheaper and more consistent control over IAQ.

About passivhaus levels which is fine. What is your occupancy per m3 of internal volume. If it's low enough the volume of internal air can buffer periods of over and under ventilation. It's one of the reasons old public halls have high ceilings. We are a family of 5 in 500m³ in an airtight build. It takes about 24hrs for the house to feel stuffy with the MVHR off.

It's entirely possible to have good air quality without airtightness and mechanical ventilation, you will just use a lot of energy forcing air through the vents using convection. What kind of data do you have on your own house?

Why do people resort entirely to emotions when making decisions about their own housing? I have very bright friends with strong scientific backgrounds who consider airtightness and mechanical ventilation as some kind of voodoo. They refuse to do the sums or accept scientific papers with the same ferver as a creationist flat earther. What is it about our own homes that makes us morons?

Might be less work than you think. 2 plasterers did ours (48m) in about an hour and a half.

Nicely done. I wonder who could have done that. (Mk4 mondeo Titanium btw?

Airtightness.

Exactly this. https://passivehouseplus.ie/magazine/insight/the-small-passive-house-problem-a-solution

Bin the aircrete and the PIR. Dense blocks and mineral wool batts in the cavity will out perform it in reality.

Any drawings of your roof and wall interface? If it's complex then I would recommend moving your airtight layer outboard of the rafters.

Seal any air paths too with acoustic caulk.

No calling me by my real name. This is supposed to be an anonymous forum.