torre

I dislike Thermalites too. If it helps, for a new build the limiting value is actually only 0.26 (table 4.1 of Part L) which gives you flexibility to use a different block, as long as you make adjustments to improve efficiency elsewhere - it may be easy to add 10-20mm of PIR to your roof or floor, say, to achieve the same SAP score.

Close ups at both ends would really help. Pausing the video it looked like the steel doesn't/didn't even bear entirely on the padstone. Can't tell if it's not quite level or just packed with something but if there's more load on the outside edge of the steel maybe that caused the crack? The other end of the steel looks to sit right at the opposite edge of its padstone too.

Point them towards VAT Notice 708 which covers this. Specifically section 3 about zero rating, then section 14 about building a dwelling which means that consequently they don't need to hold any certificate before zero rating. It's reasonable for them to request a copy of your planning permission as evidence they can zero rate. I can see why small businesses may struggle to get this right (the first couple of times they encounter it anyway) but that's no reason to expect you to pay 20% extra for something. If they've already issued an invoice, they may want to give you a credit note (for the 20% they've applied incorrectly) instead of modifying the original invoice, but then you'd still only pay the balance (being the zero rated cost)

This works really well for Dritherm and Isover https://www.amazon.co.uk/Bahco-PC-22-INS-22-inch-Insulation-Saw/dp/B003Y3SJMG the deep blade makes it easier to cut square. Compressing the batt with a plank on top helps too. Not tried it for woodfibre but have used a fine toothed handsaw which cuts really well. Lots of dust released doing this so wear a mask

How deep are your pockets? Have you looked at Idealcombi Futura+? If you're looking for better u-values but not necessarily timber clad then Decalu 88 Hidden might fit the bill too. Not a personal recommendation for either, but these are solutions I've bumped into researching options for our build

6 years payback for the whole system sounds great but payback for just the battery sounds like 8200 / 650 = 12.6 years . That's pushing the lifespan of the battery to payback at all. Factor in that battery prices approx halved in 5 years (and keep dropping) and I end up thinking that (unlike planting a tree) 'some time in the future' always ends up being the best time to install a battery. Using the above figures as an example, you could instead start without a battery and spend 5 x 650 = 3250 on 5 years electricity and as long as by then the battery price has dropped to no more than 5k you'll still be better off buying later. (and have a new battery) +1 for the heat pump dryer but drying times are much longer. Great if say you work from home and can make those longer cycles work, esp off peak.

A fire rated glass partition where the plans indicate a reduced height wall might be one solution for this, still giving the look of openness

We have experience doing something similar. Build up the blockwork first (think that's recommended for full fill inflation anyway) so you can be sure you can keep the ties running downhill. An insulation saw makes the vertical cuts @Tony L mentioned easier. The insulation should match the blockwork coursing. If you do the insulation yourself you'll be fine, if you leave it to brickies make sure they don't just let the tie drag the insulation down. You're right the coursing will run out, think in terms of 5*86=430 Vs 2*225 = 450 though You may want to use slightly longer ties to make up for them sloping down. You can also get two part ties but they're expensive.

The layout makes clearer what you were saying about wardrobe space - I'd lose the insulation rather than the wardrobe space (you'd need to lose quite a bit of wardrobe width to avoid feeling like you're squeezing around the door) As built does look a fair way from as designed - more like 1900 height than the 2100 planned and you should've had about another stair's worth of landing depth to work with too (and a bit of leeway to move the door). Did you have to make changes along the way? I'd measure that landing depth just to be sure it won't cause a BR headache later.

I don't know exactly how SUDS works in Wales sorry but for there's a recent rainwater harvesting thread here, might that be an option? Or an attenuation tank? Long shot but are you 100% sure as a replacement dwelling you're increasing the affected area enough to even fall within SAB approval?

I'd probably cut the insulation back as a preference for where the door is hinged, but @TerryE's solution is neatly done. (Separate point - the landing didn't look much wider than the door opening so have you checked it is as deep as the stairs are wide for building regs?)

What have they inspected? Just a trench or pipework and stop tap etc? I'd contact them and be up front you realised it's in the wrong place and dig another trench

On a narrow stair you'll already be taking more care and cope better with a shallow landing, plus it's much less likely more than one person will be sharing/passing in the space. Anyway you won't change the regs, you'll have to compromise somewhere. It looks like you might need to swap the top half landing for two quarter landings or similar. Don't you have plans for this? What stage are you at? Try planning just the top half of this using stairbox as suggested.

I don't think this on its own is a problem, but the end of the strap will still need to fit over the outside of the blockwork . It wouldn't be enough to fix with plugs etc to the inside of the blockwork (if that's what you're intending) - it's the difference between the whole folded area of the strap resisting pull forces versus just two or three plugged screws if check with building control that they'll be happy with what you're suggesting - it sounds so sensible from an insulating perspective you wonder why it's not the norm?Maybe just a bit harder to build, or maybe the people who think most about insulation would've already gone for a warm pitched roof

Maybe that wall is needed for mid span support of the last full width truss, given most of the kitchen and dining ceiling joists then hang off that?