PeterW

You’ll need to check with the TF manufacturer that the frame can take the additional load of the larch cladding but that’s a similar design to @JSHarris and the larch is attached to a set of counter-battens

Its difficult to do as it doesn’t polish well due to the strands. Better to scour off and then resin

External ones...? I doubt they will meet any UK standards, and the shipping will be eye-watering I expect.

How much can you do yourself ..?? That’s the big question and you need to honestly answer it.

2 storey rectangle, brick and block with concrete tiles and uPVC windows.

I can concur with that ..! We used a 63mm duct for electric and the 25mm cable was an utter cow to pull through and caused no end of issues at the house end.

None... nothing .... nada... its a skin only.

There should be a purlin both sides. That takes the roof weight so nothing else needed (no ridge beam @ProDave) Those others are ceiling joists and I’d be inclined before you remove the old ones to use that as a platform to install some new ones higher up, then remove the old ceiling. Downside will be the whole lot will need to be brought up to building regs and you’ll possibly have to use PUR as the rafters aren’t that deep

The one with the red arrow ..?? Looks like a purlin

Is that a purlin on the left side resting on the brickwork ..?? Got a better image of the left (and right) just above the ceiling level..?

This is the safety zones for glazing from the current Building Regulations Part K 2013 Full text here https://www.planningportal.co.uk/info/200135/approved_documents/73/part_k_-_protection_from_falling_collision_and_impact

You could use one of the kits from Wunda - they do a variety of them that are suitable for smaller spaces and attached to existing systems. The downside is unless you do some clever use of zone valves, they will only operate when the main house heating is switched on. https://www.wundatrade.co.uk/shop/home/water-underfloor-heating-kits/small-area-kits-52m/single-loop-pumped-kit-joist-panels-2-x-channel/

Is this having a bathroom in it..??? Bearing in mind you'll have finished the house one before this project starts won't you...??? ??

300mm horizontally is the recommendation but it’s not a regulation.

I’ve just used an online company and £1200 for 4x2.2m with 4 panels and 2 tilt and turn. That’s for uPVC @craig what’s the biggest unit you would do..?

Not single panels though ..? Even at 950x2150 a triple glazed panel would only be 63kg. So the total window is only going to be 300kg or so. Double will only save 21kg per panel.

I use Estimators Online

I’ve used uPVC and the frames were no thicker which I suppose is a benefit of that sort of system.

Weight of what ..??

Because its a standard detail and doesn’t need an SEng or anything that you can’t buy from a builders merchant. Also, it can be done by any builder, the only amendment I make is to full fill the cavity below ground level with EPS (as did @joe90 ) which reduces the losses through the slab edge more. Ground bearing slab is ok but needs an SEng to design and sign off.

But that’s the same as a ground bearing slab ..?? It is the final floor too, just edged with blocks.

Cheapest way is a ground bearing slab, with insulation under the concrete slab and blockwork on strip founds. Are you going for brick and block or block and render ..?

Got to wind and watertight on a 165sqm detached brick and block house with 3 rooms in the roof for £58k ... that also included putting in UFH pipes.

Sorry - bit of PTFE and do it up F.T......

The only restriction will be that if it is below a certain height then it has to have toughened or laminated glass in the panel.