Mr Punter

It looks like the lining will go in there fine. Some decent screws and foam and it won't budge. You could even have a deeper lining if you want. That way you can get a few more fixings in.

I meant opening inwards in the photo you posted - in to the existing room. Assuming you have some steps going down into the new bit, I don't know how it would work having a door opening that way.

Plasterboard is neat enough. Also more fire resistant.

If you have right of access over the land this will normally be inherited by the other plot(s) you create. Clear this with your lawyers before submitting your planning application. The boundary issue and the location and ownership of the fence is a separate issue from the access rights and should remain so. Boundary disputes can be acrimonious and expensive to resolve.

That was indeed a lot of trusses. A fair size house. It will look a better fit once the scaffolding is down. Was this a replacement dwelling plot?

Looks like the door will need to open inwards. You could have a bifold style if you need to save room and it will be open most of the time.

Hardwood kitchen worktop might work for your treads.

Ask them to look again. The A393 is fairly hefty. Maybe it could be beefed up locally if required.

For a small bedroom this is £450. It looks a pain to install. New floor coverings and decoration also may be tricky and there are loads of connections. I would also be concerned about ongoing product support / supply and any room alterations. For the money I would have UFH or have a top range rad for £100 and spend the £350 elsewhere. The only application I would consider this for is on the ground floor of my house on the flood plain. At the moment I have MDF skirt and normal rads but in the event of a flood I would consider changing to this. It may be an avenue worth exploring for the suppliers. I am not sure if they sell the skirting without the pipe - for small WCs and the like?

I think you are best asking the engineer. Try not to damage any surfaces that will remain.

Is it the case that you have a ventilated loft and holes in the ceiling? You can often just seal over these for the test. The test result should be something between 1 and 20. You should be able to achieve 5. It is for air permeability and is in m³ / (h.m²) @ 50 Pa.

Thanks Damon. That may work well. Do they count in SAP? Do you have a suggested make? What rooms do they go in?

As it stands, with gas heating, the heating cost for the 1 bed flat will be about £100 per year. Water heating is about £80. There is a limit to what can be sensibly improved by adding insulation. I could put some heat recovery ventilation but it would need to be small and idiot proof to run.

Agreed. With gas boiler I would only have PV if the SAP says so.

It just seems that anything other than the gas combis equals potential issues. The large cylinder would need to be sited somewhere. The flats will have their own water meters. I need the option to sell individual flats, or I lose a lot of investment value. As it is a flat roof there is no way that adding PV will be lower than waterproofing. If I have to go the PV route I will probably do as you suggested earlier and put it into the largest flat.

Each flat to have their own meters. The PV was to help with SAP calcs but I would happily ditch it if it still works out. I just thought I would go with the decarbonise the grid and make Greta happy but the more I look at it the harder it is not to go with gas combi.

I have had specs where the base of columns is wrapped in fabric mesh and encased in concrete to prevent corrosion. Unless there are very adverse ground conditions I cannot see the issue.

Yes one supply per flat, but I agree it may be best for just one to have the PV. I don't think it harms the SAP calcs for the block.

The full wheelchair accessible standards in part M are pretty onerous. Very unlikely you would ever recover the costs in rent.

If it is above ground, a coat of primer and of bitumen paint will protect it.

The issue I have with the PV is that if I split it between the flats it is extra cost. I can (I think) just have it all to one connection.

With that kind of price difference it is very difficult not to go gas combi.

Thanks. Yes I was aware of this. The land is being purchased by a subsidiary company. I am not sure of how it works - I leave it to the Beanies.

My concerns about gas are the extra hassle and cost of installation, fire safety and environmental but your points are well considered. I would not, in any case, have a system boiler in such a small flat but a combi is very tempting. Hmm...

I can see why you and @SteamyTea like the storage heaters but I may favour panel heaters. With heat pumps, I did consider just split a/c units to do heating and cooling, rather than a full on air to water setup. I have only used an old school electric shower gravity fed and it was woeful. Would a 10kW unit be considered OK by tenants? A 1 bed flat is about £850-£900 a month, so they want it to be reasonable.