ETC

No - I’m suggesting you take up all cavity walls to the flat roof. The only wall that’s not a cavity will be the wall between the staircase and the bedroom which you can either build as a traditional timber stud wall (insulation between and inside with a vented and drained cavity or take the 215mm wall up and insulate the inside and clad the outside. Once you’ve the cavity walls built up clad the outside with vertical and horizontal battens to create the look you want.

Also why are you building a cold roof? For the corner use a Keystone post and lintel system - simple.

The easiest thing to do is to build the walls as cavity and then build out in timber to create the look you want. Keep the window recessed.

https://www.buildingcontrol-ni.com/assets/pdf/TechnicalBookletD2012.pdf

Really……

What about sound resistance between floors?

BCNI_CONSTRUCTION_DETAILS_-_November_2023.pdf

Why are the doors set that far forward?

Out here in the provinces it’s not acceptable since it is too difficult to administer - but then again we are a bit behind the rest of the UK.

I don’t think it’s a conditional approval - more likely a Plan Approval with a note on a drawing to say that certain information will be provided at a certain stage which puts the onus on you to provide that information before you can get a Completion Certificate. This is done quite often for elements that cannot be fully designed until a sub-contractor is appointed such as timber frame, trussed roofs and the like. In your case if an engineer designed a roof and submitted a drawing but no calculations I wouldn’t be too worried and would stamp the application approved - calculations will be filed.

Nope - not acceptable. Can’t condition a plan approval.

Put a service void in front of the plasterboard.

Just give your local British Gypsum rep a call. He/she will be more than delighted to design and specify the wall. And yes - no foam - fire stop with an appropriate material.

If it’s just rainwater from a roof gutter you don’t need a gully trap.

Water butt.

Can you retrofit a direct air feed. Most stoves I see - especially greater than 5kW are fitted with a direct air feed.

NB

Internal.

800mm-1100mm for standard windows. Can be reduced to 600mm for roof windows. Don't forget - if you are NOT introducing a new bedroom AND you didn’t have an EEW in the bedroom before you did the work BC won’t ask for a EEW.

Make it up with links but check the spacing first. Might just be 40mm/50mm from top and bottom for minimum cover.

Standard two storey house fire doors not needed (except between an attached garage and dwelling). You’ll need EEWs to new created bedrooms on the first floor. No new rooms = no new EEWs.

Yes. 50mm air gap is normal.

Check your SAP for your floor insulation requirements. A 1200 gauge DPM is a minimum requirement. Don't forget about a VCL and perimeter insulation.

That’s the stepped DPC above your window. A cavity closer will be either a rigid board like Supalux or a flexible friction fitted sleeved mineral wool closer like the one I posted earlier. I don’t see a cavity closer and the insulation is “wobbly” because it’s just set on top of the stepped DPC and fitted without any wall ties or retaining clips and that’s probably why it’s not sitting flush with the inner leaf.

Yeah - replace it.