JohnMo

Which bit is kitchen?

Every time I've used self leveling, you have spread to the desired level and taper the edges smooth into the high spots. The self leveling bit, is any tooling marks smooth themselves out.

You might hope for that, but you will never know.

If your extract is performing poorly, either it's a rubbish extractor, or it is positioned too high on the wall. Our new kitchen was installed a couple of months ago, our extractor performed rubbish. Read the instructions and it said to install 450 to 500mm above hob. Measured and it was at 750mm. Rang company and they stated that the dimensions they alway use. Got them back to install as per instructions and it works great. Recirculation or extract outside your call.

Heard of them, if you look on eBay there is one going quite cheap , not sure if it matches what you need.

We did 3 coats, 2 costs prior to anything being installed. A finish coat after

I would go for a decent natural slate. We used Cupa Heavy 3 slates. Looks good and the roofer likes to use them. Not that expensive we purchased just prior to brexit, so not sure if prices have changed. But if you are matching existing slates, talk to a Slater.

We left enough DPC sticking out, so we could have DPC between the slips that are above and below it.

Best to get a colour card, from your paint supplier. Select a colour you like and get a sample made up. Try the sample in the area or areas where you intend to paint. Let it dry before you say yes or no. Colours change in different light, what may look great to me in NE Scotland, may look rubbish with your light. Good luck

Not sure if you have purchased the controllers/ thermostats, but you will find the reaction time of the slab very slow and once heated, slowly gives heat to the house. We have around 100mm screed and ended up taking all the smart stuff out, as it couldn't react in the right time frame. Now have a thermostat in the hall that can call for heat, and one in each bedroom, they cannot call for heat, but can stop it earlier than the rest of the house, so the bedrooms are cooler. Boiler kicks in for a few hours once a day to charge the slab, even though same heat is set on the thermostat all the time (24/7). Thermostat is set to 19 degs at moment, will drop to 18.5, as slab is in the heating phase and overshoot to 19.5, if the sun comes out, the evening temps can be around 20 to 21 degs.

How thick is you screed and how well insulated are you?

Semi rigid 90mm via plenum box. Ease of DIY install, but also very quiet in use and no cross talk. Most of mine is also going through Posi rafters and there was not enough room to install rigid. If doing rigid, use metal pipes only, most plastic bends the radius this too tight and you get a large pressure drop. Blumberg may be the exception, as their bends have a larger radius. You will also need an attenuator at each outlet to stop cross talk.

Stick in an electric element and have its own thermostatic controller. Something like a Termo One. Then you don't need to fire up the central heating in the summer to just heat/dry some towels.

Just moved out of our previous house, built in 1830, still has most of the original timber framed windows. If they are painted correctly no issues. The replacement windows we installed in 2012, are still good, no need for paint for quite a few years yet. If the windows are factory finished and are good quality windows, see no reason why you should not see 20 years, without the need to repaint. And if fashion's change you can change the colour easily.

Any reasons? Assume you don't have UFH

You can run all your pipes in plastic barrier pipe, except within 1m of the boiler or hot water cylinder. You could also leave the gas boiler there, as a fall back if you have maintenance ongoing on the ASHP, or in very cold weather when the cop is less than ideal. A hybrid system.

We went 3G wood. Eucalyptus, factory finished. Main reason they are made about 3 miles from the house. They came measured, manufactured and installed. So basically any issues were down to them to sort out. Happy with the results. But wasn't cheap.

You can get wood coloured marker pens for that specific type of job. Or use you kids felt tips and then wax

Your all lucky, our front foundation width was closer to 2m wide and reinforced. All the fun you have an a sand hill.

Used 90mm to keep velocities down, managing to use a single run where in 75mm, it would have been ideal to run two runs to the outlet. No issue getting bits.

To answer your question, structural calcs would need to be redone

Schools and COVID precautions are not really appropriate settings to aim for in a living or sleeping space. My recommendations are taken from. https://www.paulheatrecovery.co.uk/air-tightness-standards-testing/

eBay - GRANT HPID6 AERONA³ AIR SOURCE HEAT PUMP 6kW INVERTER DRIVEN ASHP inc controller £2k. Others available from £1200. 300l uvc pre plumbed £1k. £1k for stuff and install. My price does not include UFH or radiators.

Or buy one yourself at the time get local plumber and electrician to install. £3-4k all in, instead of £15-17 being quoted on other threads, they may get a fair bit back over 7 years, but have to spend now.

I would strongly suspect 4x2 3mm wall steel (not iron) over 3m will sag quite a bit with it laying flat. 6 or 8mm wall would be better, the calculations would have to be done for wind and and snow loading etc. But it needs to be designed.