Mr Punter

Take it down and roof over it.

You probably don't need 50mm service void and you could go for 25mm or 38mm. Ditch the Fermacell if you don't want a fight with the sparky and plumber and plasterer and labourer and bank manager.

Modern softwood can be fairly crappy in comparison.

Cheap softwood windows can rot through in no time.

I am surprised they are not fitting a meter when they change the pipe.

If those pipes are connected to a saniflo you got what you deserved for dining with the Devil!

If this is an old property with not much floor insulation the tiles are going to feel really cold.

I prefer to build, then sell. The only choices the customer gets are carpets and I don't do those until contracts are exchanged. That way, the customer can take their time and make sure everything is OK. Don't mention the prospect of another plot, just sell the one you have for as much as possible. That will save any grief from timewasters.

Not sure if it is the same for self builders but if you detail planting and landscaping as part of your planning consent it may be eligible for VAT refund.

You can get shower valves for when the plumber has mis-piped the hot and cold. I think Grohe do them. https://www.showerspares.com/search/grohe_thermostatic_1_2_compact_cartridge_reversed_inlets_47175_000/

They are FO walls there. Wall 1 is a full 2 storeys high!

I have just had some horizontal lead flashing done on brick. They used Flashpoint sealant in the gap at the top of the lead. Looked fine to me!

WHAT??? Did you get a design stage SAP? You will need it for Building regs. 50mm Kingspan will not be acceptable. This may have been OK 20 years ago.

I would not worry about the rest of the block, just your own flat and possibly the neighbour's. A Building Surveyor would be able to visit, inspect and produce a specific defect report on the probable cause of the damp. Cost about £400.

It does not look like overkill. A friend did some gabions in his garden. They take up a lot more room than RC and need to be battered or stepped back. They are best filled by hand, which is labour intensive.

Often mould is caused by lack of ventilation warm moist air condensing on cooler surfaces. If you dry your clothes indoors, get a dehumidifier and run it until the clothes are completely dry.

Could scrap the UFH upstairs and just have towel radiators. Once you know you heat losses and DHW requirements you can work out system sizes and costs.

Yes. Be polite in your dealings and send the information requested promptly. If you are unsure what they are requesting, just ask. It is standard to request BC approval and Risk Assessments and Method Statements (RAMS) from the builder. For your work, this may be, for example, detailing how the structure will be safely supported and the new beams installed.

You don't need to connect into an existing manhole, you can connect anywhere along the line. If the pipe is fairly large you can connect using a saddle but you may need a new manhole. How close is the sewer at is nearest point?

There may be room behind the dabs to push the cables through. Could be simple, could be a pain. Try one and see!

Architect fees can be a bit steep sometimes but I can see there is a fair amount of overhead, especially for ongoing training, bidding, schmoozing, premises, advertising etc. Lots of non-billable time there. I don't know many rich architects, but lots of comfortably rich vets, dentists, lawyers, surveyors etc.

Some electric accessories have a lip around the edge that may cover this. Otherwise, could you get the backboxes out without too much damage and replace with shallower ones?

I have used Marmox where we have a single storey element abutting 3 storey, so they are on the steel beam. I think they are better at stopping side-to-side cold bridges than up / down, as they have the concrete type vertical cylinders, but better than nothing.

I knew the title would attract @Pocster.

The reason MVHR has condensate is because the exhaust air is cooled as it passes through the unit. If this is just a normal extract and the ducting is inside there will not be an issue. It can run up, down, left and right. It is only when it approaches the outside that it will possibly cool enough for condensation to be an issue.