Mr Punter

Good luck with the planning application. As others have commented, perhaps do not make PH certification a condition of your consent as it may not be possible or practical to achieve. It can be very time consuming to attempt to alter a planning condition, especially if the PH has become on of the main considerations in the para (whatever number it is now) approval.

Frame fixings https://www.screwfix.com/c/screws-nails-fixings/frame-hammer-fixings/cat840010#category=cat840068&productdiameter=10_mm&page_size=100

If there has been no subsidence I would not bother with insurance. The underpinning could just be viewed as improvements to foundations. Can you reverse the bucket on the digger?

I have never come across this. Is it available in large sheets and varying thicknesses?

There is a big water trap on a WC so you won't normally get any smells from it. More likely from the sink, where flushing the WC could be pulling the trap. Run a small amount of water in the sink and see if the smell disappears.

If you have MVHR they sometimes like a 10mm bottom gap.

On the screed is simple to do. You can always trim later if you need / want to. Make sure you set them so you have the head at the right height for your door and your floor finish.

Well that all sounds good. It is far better to check and know for sure, rather than worrying later when you have committed yourself. The path should really be 150mm lower than the DPC but if it has not caused any issues it will be fine.

Clean the materials and stick down with https://www.screwfix.com/p/sika-sikaflex-ebt-all-weather-sealant-grey-300ml/79250

Under the stairs then? Or with the shoes / coats?

I have found that even a well insulated cylinder can generate a fair bit of heat. Why not locate it in the deep cupboard next to the stairs?

On their front page they were quoting density in kg/m2. They also had no information on insulation performance. Avoid.

Hello William and welcome. Whereabouts are you building?

Use a telescopic vent with the air brick being just under the plinth brick. The vertical bit is only about 50mm wide so you can just cut the floor block to suit. Obviously you need to place between the beams. It does very slightly reduce the bearing for Marmox but it looks like the soleplate spans onto the edge of the plinth brick anyway. Make sure your ground level is 150mm below the sole plate / DPC.

+1 Insulation and airtightness need to be the priority. Spend most of your budget on this. If the oil boiler works OK, stick with it for now. If it does not heat the water, use the immersion. Forget the Sunamp and the log burner. Close up the fireplace.

I agree with (1) above. External humidity is high now and temperatures are warm. The MVHR cannot reduce that.

It is more the width of the footing. Extend it by at least 400mm on the low side and use some starter bars with hollow blocks, concrete filled. Add some weep holes low down. 800mm is no a lot but better done properly.

The render base coat and mesh is really sticky and forms a really good solid substrate to tile onto. We tried tiling onto the XPS and it just did not work.

I think that painted hardwood would look best. Other option could be aluminium.

I think we just used Weber LAC and the standard pink fabric mesh and then tile adhesive. It was on XPS.

The best comment I read was "I am a house builder and install air source heat pumps. They work very well with Under Floor Heating in our superbly insulated new homes, but they will not work well with radiators or old poorly insulated homes." It is about right I think.

I have used the plastic imitation stuff for lookilikey cast iron. For ali gutters I found Guttercrest good.

But if you were in a converted flat or even purpose built over 15 years old your neighbours would not thank you. Lots of people work at home. Up, shower, breakfast kettle toaster, kettle again hairdryer lunch, microwave, fridge, computer printer, TV, lighting, cooker. Face it there is no way a normal person consumes 80% of their electric between midnight and 7:00 AM. Post up your last 3 bills and it will either prove me right or prove that you are not normal.

I recommend the non-slip textured GRP tread covers for those steps. I fitted some to some knackered outside steps that I would otherwise have had to re-tile.

With Economy 7 the night rate is 41% less but the rest of the time it is 16% more. Nobody in a flat wants to cook their meals or do the laundry at midnight so it can often end up costing more.