Mr Punter

I think B01 should be the same depth as the others but this was not supplied as part of the package so the builder got the nearest size conventional joist from a merchant, was unsure of how to make it fit, then sort of split the difference. Also I would be interested to know if the decking was D4 glued and screwed?

The GSE system is fully tested and certified as well as having an insurance backed guarantee. If you installed to the manufacturers instructions - which it looks like you have - you could look to them for a remedy. What you clearly need to avoid here is any risk of this recurring and I think it should be down to GSE to come up with a solution.

Regarding windows, unless it is a conservation area you can do your own thing. Have they requested samples of materials prior to construction commencement? If not, as long as the walls and roof are similar to the existing house you will be fine.

If you have a 300mm cavity, stainless ties will cost an extra £2.50 per metre and insulated ones an extra £7.50. Have a looks at http://tonyshouse.readinguk.org/ as he has done a conventional construction with concrete intermediate floors, which would help towards the solid feeling you are looking for.

What are you using the attic for? In my experience, unless it has proper staircase access it will only be used for storing crap / suitcases / skis / snowboard / old kids toys.

I have often found window manufacturers and fitters to be very slopey shouldered.

Hi Graham A section drawing through your current reveal would be helpful, as would a current photo from inside and out. When you mention the textured finish, is this intended to be "wood grain"?

When my floors use engineered joists I specify that the maximum acceptable deflection must be the lesser of <8mm or 0.002 span, NHBC allow 12mm and 0.003 span, which I feel is very bouncy, but is probably aimed at house bashers with more of an eye on costs than customer experience.

The section you posted shows a 215mm concrete inner leaf to the wall. Why has this been specified?

I much prefer this to the suspended timber floor.

This is one for your engineer. We have just done a project which cantilevers over a retaining wall and a river. The engineer designed a piled foundation with cantilevered ground beams so that the piling rig could still operate within a safe distance from the retaining wall.

Work to the floor is notifiable as it is a thermal element. £324 sounds high for the fees. Should be £170 ish. They will not need to initially visit. https://www.adur-worthing.gov.uk/media/media,140420,en.pdf https://www.brighton-hove.gov.uk/sites/brighton-hove.gov.uk/files/Fees Merged 2018 A.pdf

Population = 105 so don't fall out with the neighbours!

I would wait until it dries out and apply a clear coating of silane / siloxane. If you leave it wet, it may get damaged by freeze / thaw.

Most brownfield land has small quantities of contaminants. You may need to commission further WAC testing to see how the material should be classified for waste disposal (inert, hazardous etc.) as this will influence the muckaway cost. You may need to replace the soil in any soft landscaped areas with new and have it re-tested and a verification / remediation report.

If you are doing a new build, get your architect / technician to do a "Full Plans" building regs submission. This should specify how each of the regs (structure, fire, conservation of fuel etc) will be met. It may be that the submission gets full approval, so you can just go ahead, conditional approval, saying that some further information will be needed down the line, or refused, which means you would need to reapply. It is possible to go ahead just by applying for a "Building Notice" but this is really only suited to minor works as you run the serious risk that at any stage the building inspector can ask you to re-do what you have done. The benefit of having full plans drawn up, with a specification, is that any supplier or contractor can see clearly what they are intended to do and as long as you build according to the approved plans the building inspector should be (fairly) happy.

If the batching plant are using frozen aggregate and cold water, the concrete is going to arrive very cold. I would wait until you have a few days where it is milder and overcast.

I have used it. Works very well. I prefer the larger gravel as it does not get picked up in tyre treads or footwear. Don't make the gravel too deep.

Can I just mention that this is my favourite topic title in a while...

I am always keen on photos. How much concrete did you have and how big a queue of traffic / rage did you generate?

I like the breakfast bar. Is it stone / quartz? Every kitchen = row of chipboard boxes lashed to the wall.

Instead of the single storey lean-to, If you move the wall back by 1 - 1.5m on both floors the difference in cost will be minimal and the LPA may accept this as a minor amendment. It also means you will not have to provide support for the upstairs storey, which would likely be tricky otherwise. There will still be some visual relief in the rear elevation but the remaining wall will not impede your view of the garden so much.

There are tax implications in doing as you suggest and unless you are an experienced developer I would suggest selling the plot for house B and using the tax free proceeds either to build the proposed new house or to live mortgage free.

If the steels are semi exposed I would galvanise.

The proposal looks fine as it will vent under the blocks and you can it the vent on the beam DPC. Do you have any vents where the beams run parallel?