Dunc

Yes was hoping to install the stairs myself.... Yes, stud walls are full height and already in place because they are structural racking. Only the stub wall is not structural. I suspect that one at least will have to come out. I'm reassured that I haven't missed something obvious!

I need help understanding how a winder staircase can be installed in a fully-enclosed stairwell, please. CAD drawing shows the as-measured openings between stud/structural walls. Architects plans for context also attached. Stairbox have suggestd an over-stringer width of 1000mm which in principle fits with 20mm tolerance. However, the newel post at the inside corner of the winder overhangs the stringer by 29mm which means it doesn't fit between the walls. They suggested trimming back the studs on the inner corner to set the newel post into the wall. But I can't see how the stair would be constructed and inserted into the available opening as the newel post would have to pass all of the other studs first if the upper run is installed from the first floor with the post attached (which I belive is how it's usually done?).

I need to install the MDPE water pipe from my boundary box to the house. There is no option but to have it under the driveway, which will be gravel over MOT. I'll bury the pipe at least 900mm down. Should I use a duct in the bottom of the trench, or will a bit of sand under and over the pipe be sufficient? Ta.

+1 on the Huepar. I was a bit shy of spending so much money, but I've found it to be a very useful tool so far in the build. Way better than a single-line red DeWalt I had borrowed initially.

To be clear @Nickfromwales whichever scenario is used, the soil stack and AAV (and everything else in the drawings) are indoors on the first floor - the soil stack does not penetrate the ceiling or wall here it just drops to below the slab and exits there. Hence the requirement for the AAV inside to let air in. Gas venting is outside. Access not a problem as this is all in a service coomb behind a false wall. Does this change your view of Option A?

In the upstairs bathroom I have bath, then sink, then toilet running "horizontally" (18mm/m fall) into the vertical soil stack. I need to install an air admittavce valve for the stack. Venting is provided separately, outside the house. If I install as in (A), in the highly technical drawings below, is there risk that the bath and sink would be vacuumed by the toilet flushing? Would (B) be a better arrangement?

Two good suggestions there, thank you! I take it you agree it's worth sorting, rather than ignoring. I guess the squirty foam might be easier. Getting the osb off, having already been thoroughly taped up would be difficult. The tape tends to rip the green layer off. Is all expanding foam equal? Not sure whether the expense of the illbruck airtightness foam is necessary, being on the outside of the airtight layer?

The cellulose insulation was pumped into pur larsen truss frame last week. The installer noted that at each velux window there is a small-ish gap between the head and foot trimmers and the airtightness board about 25mm. Not possible to pump cellulose into such a shallow void. There is insulation behind the trimmers, of course. The TF company have dismissed the gap as "too small to have any impact"...I'm disinclined to accept that when chasing marginal gains in Passive type builds this is a reasonable thing to ignore. Am I being unreasonable? If not, suggestions for a solution?

Scotland - north east highlands. Not sure they're local; think they're travelling from Essex!

MBC are using R.Warville (JW- Insulation.co.uk) for my insulation blow next week.

Dunno if it's in the spirit of the forum to disclose company names? @Buildhub Moderators can delete if required. These are windows from NordVest. Have checked warranty detail. 2 years parts & labour, 5 years glazing & labour; further 5 years glazing but no labour....just shows how variable warranty can be. Perhaps I should have looked into this in more detail when choosing a supplier. But the headline "10 year warranty" seemed comparable with others. Doesn't fill me with joy for the long term. However they have accepted the warranty claim with fairly minimal fuss (a surprise based on previous issues). So new glass is on the way.

Dunno if it's in the spirit of the forum to disclose company names? @Buildhub Moderators can delete if required. These are windows from NordVest. Have checked warranty detail. 2 years parts & labour, 5 years glazing & labour; further 5 years glazing but no labour....just shows how variable warranty can be. Perhaps I should have looked into this in more detail when choosing a supplier. But the headline "10 year warranty" seemed comparable with others. Doesn't fill me with joy for the long term.

When we were getting quote, cost difference between 2g and 3g was about 10% from the same manufacturer in my case. Much smaller than expected.

My timber cladding reveal boards overlap the aluminum of the window which itself ovelaps the glazing unit - they'll have to come off unfortunately. Doable, but irritating given I only finished installing today.

Not bl**dy long enough 👿