Mr Punter

A great looking job @Cpd. I can see how careful setting out is crucial for this.

Can you have a thumb turn on the inside? Or an escutcheon outside?

Non material is a change that does not alter the footprint or elevational outline and does not increase overlooking or alter the visual impact, so window and door sizes and locations are typical for this. Other changes - like change roof pitch a bit, move external walls a small amount but leaving the scheme fairly much as per the approved scheme can be dealt with as a minor amendment. Bigger changes need a fresh planning application.

The stuff they used is like a hard rubber when cured.

5mm sealant is not at all unusual. I would go for a decent bead all round. I have go some glass panels fitted to the river wall and there is about 15mm mastic either side of of the glass.

It should be done as a non-material amendment and is fairly simple. There is not normally a consultation period. It does not result in a new planning consent. Should get a decision withing a month but will probably take 2.

The grid mat stuff is really expensive. Can you just put this adjacent to the road and also in the turning areas? The remainder should be fairly stable if it is just being driven straight over.

My experience with working prior to pre commencement conditions approved is that it depends on the work and the condition, so, for example, if you excavate for foundations without having all the external finishes signed off they will let it go. If you mess up the road when you should have submitted a wheelwashing scheme for approval you will get done. Like @Russell griffiths said, why not just get them signed off so you can work undisturbed?

Ours was less than 100mm insulation - it may have been 50mm. Below ground we stuck an extra 100mm on the outside and we only did ICF for the basement with the rest in timber frame. Here it is with the timber plate. It worked well with this brand of ICF as it fitted into the profiles just like the polystyrene.

Using this approach, is there any issue with sound travelling between the rooms - along the plasterboard?

I have done this with Polarwall. We just fixed coach screws like these https://www.screwfix.com/p/turbocoach-coach-screws-yellow-zinc-plated-10-x-75mm-50-pack/9897g into the back of the timber plate at 400 ctrs so it is locked into the concrete. You could add another timber to the front if you want to hang the joists from the top flange, but joist hangers may work out cheaper.

The roof is OK as will be the skylights if they are correctly installed. Once you have the placed sealed up you will be able to see if you have an issue. You need to make sure all the junctions are completed and that DPCs, DPMs, flashings, copings etc are all correctly detailed and installed.

I think it is to do with relative humidity, where when the outside air is colder than inside the RH will decrease when it is warmed by taking the heat from the exhaust air.

Have a look at https://www.breeam.com/ and https://www.designingbuildings.co.uk/wiki/Embodied_energy_in_construction This is a fairly well covered theme in the industry.

No, being allocated a postal address does not make you liable for Council Tax.

Embodied energy of materials is what this is all about.

A fan heater may be simplest and cheapest. Underfloor may take too long to heat up. Don't concern yourself re: lighting and TV running costs (if they are newish) as the heating will be many times these.

zinc is used as well. Be careful when mixing metals as some can corrode others when in contact or even nearby. I think lead is safe with most.

Do you use this to store large hairy men? A bestseller in nearby Brighton no doubt.

You may do better to send your design to some ICF companies for pricing and they should know enough to highlight what may be tricky / expensive. Also, things like cill and lintel heights can make a difference to how easy to build with some systems.

Maybe have a chat to find out what Building Control and the Warranty provider are looking for. Strip footings are often the most economical. Does Mr Builder do beam and block or concrete ground bearing for the ground floors?

If they can make it comply with FEE by making improvements elsewhere there is nothing fraudulent in having no test and air leakage the default 15.

Actually just looked back at what we spec and it is the lesser of 8mm or span x 0.002, so a fair bit stiffer.

I think the danger would be if you have submitted building regs drawings with insulation and airtightness level of X and claim for RHI that it is Y, there will be an easily provable case of fraud. If you use the default value for airtighness instead of having a test you will save on the cost of this and it will be used for the EPC. At 15m³ / (h.m²) it is three times worse than you would normally achieve and fifteen times worse than the best.

There is means of escape from each upstairs room. I would have heat detector in the kitchen and smoke detector in each bedroom, all mains and interlinked.