Mr Punter

I am happy for it to beep when the timer is up, just not every 30 seconds after. I hoped that there was a built in microwave that does not incorporate this "cunning" feature, or at least allows me to turn it off.

I have a built in microwave and when the time is up it beeps. Useful. Sadly it continues to beep every 30 seconds until the door is opened or another button is pressed. V. annoying. There was no way of turning off the repeating beeps. Said microwave has now crapped itself and I would like a replacement that does not continue with the needy beeping. I tried some appliance suppliers who claimed this to be a safety feature but I cannot work out how it is unsafe as the beeping does not start until the microwave has stopped heating. Does anyone have a built in microwave that doesn't repeatedly beep, or are they all just annoying?

I don't think there is much difference in cost between a metal web engineered joist and an OSB web engineered joist. If you have trusses and no ridge beam you would need a chord lower down and would not get the vaulted look. The zinc is probably expensive.

Given that the floor was designed - I assume at your request - for 8mm deflection, there will be loads of spare capacity for the extra board layer. It is probably equivalent to having and extra 2 average sized people in the room. I would just get on with it.

If you intend to insulate this between the joists with no airflow over the insulation it is very important you have a properly fitted VCL on the warm side of the insulation. With your downlights and MVHR ducting this will be very difficult to achieve so the roof will be at high risk of interstitial condensation and premature failure.

It won't be much use for sound insulation. Can you use it in the centre of the slab and use the better stuff around the perimeter?

That is a bargain. I can only just lift a 25mm sheet of OSB / ply. Hernia time for me!

The diagonals are bracing. It could do with an additional horizontal rail at each lift and a toe board but not an immediate hanging offence and if I was the only one working on it I probably wouldn't bother.

I always go 610 unless it is integrated.

I would do clearance holes through the battens - maybe 5mm so you can load the screws. Assuming you have lots to drill, you could stack the battens and do 3 at a time. Once you have set one up you can use this as a template. If screwing into the rafter without a pilot is tricky you could do a 4mm pilot but not full depth.

I can't work out why the builder is so concerned about rendering before the windows go in. Just bead up the openings and render, measure finished size, order windows, paint render, install windows. A good benefit is that the windows will not get damaged by render or paint.

£200k for brickwork is loads. The contractor should be asking their QS why they missed the Flemish Bond spec.

I have only seen it used for the mains supply up to the cutout. Sub main in SWA.

I would really press the engineer to let you use 140mm blocks. Most garages are 100mm single skin with a small pier midway. Also there is a lot of work in those dormers for not much more space. Can you lose them and have roof lights, or are they a planning thing?

Can you post a drawing? What is the steel supporting? Part A of the Building Regs approved docs may be worth a browse.

I am not sure if it would be feasible to trim and modify the trusses and have them sit on the bottom flange of a steel beam so that the original ceiling height is maintained throughout?

The Velfac / Rationel / IdealCombi family of composite windows all like a gap around the window of about 10mm which get filled with Compriband expanding tape. If you are rendering, you need to get the render on before you measure and fit the windows. Not too difficult. This leaves a nice space inside for insulated plasterboard. If you go for an all ali window the u-values can be pretty poor.

I assume that it is B1 that is an issue, so nothing to do with bifolds? The span for the knock through is really wide and needs a deep beam to provide support. 400mm drop down into the room is a lot though and I can imagine spoils the open look. Perhaps a bit more thought at the design stage would have given a better solution.

Is this not the side elevation, flipped and with less detail? Just send the drawing.

You could just time how long it takes to fill a 5 litre container with the kitchen sink cold tap on full.

You would do well to check the pressure and flow rate of the incoming main, as that will be a limiting factor in the performance of the combi.

With your drainage, the pipes need to go right through the blocks.

You mean the Teplo basalt ones? Crazy expensive.

600 for external walls means more space for insulation.

I don't really believe in the cleaner. Just leave the expanding foam can attached to the gun at all times, even when it is empty.