Mr Punter

If it is softwood boards, no need to pre-drill. Leave the nails. Screws like these https://www.toolstation.com/floor-tite-tri-lock-pozi-screw/p51501 Make sure you hit the joists.

From the photo it looks like about 600mm from pavement to threshold. There is not enough room to make a ramp for a wheelchair and a standard wheelchair cannot negotiate steps. You would struggle even for ambulant disabled access.

Cut a piece of timber batten and slip it behind the existing plasterboard at an angle and fix through either end with a screw. If the hole if too fiddly for you to get in, mark it out and cut it bigger. Cut a new piece of plasterboard the size of the hole and screw it to the batten. Fill, sand, repeat. Paint.

I would make the porch bigger and have it properly double fronted. I had a Victorian house a while back that was a similar design but a bit smaller. Sadly it was on a main road, the chimneys compromised some of the rooms and it cost a fortune to heat.

I have tried a repair with a bag of the cold stuff but it was hopeless. Sticks to your shoes and gets trodden everywhere and it never seems to go off.

I prefer traditional screed. They do it readymix with fibres and drop it to site. It goes in a bit thicker. If the screeders are good it is a superb finish. I suspect it has better adhesion for tiles as it is not so smooth as the liquids.

By strange coincidence I just got an email from the purchaser of the house where we installed the type C system. 8 years from completion, has since been sold on and there is a problem with the basement. I assume it is a failed pump plus lots of rain. I have put them in touch with the contractor. I can't say I am a fan of below ground basements and I can see why the warranty guys want 3rd party warranties to escape any liability!

Class Q is for conversion, not replacement. If you have removed the barns you may be a bit stuffed.

Sensible question. We had some floors done with a few years back with anhydrate screed and there did not seem to be any laitance so we did nothing. We tiled and had no issues. If I was doing it again I would use the concrete based one because I am liable for 2 years after the property is sold. Removing laitance is not something the tilers or screeders would take on so it would be left to muggins and I don't fancy it.

I think an issue may be that you cannot inspect the concrete of the join at the floor / wall / kicker junction so SIKA are unlikely to guarantee this. In my opinion, if you are made to use type C anyway, you may as well save your money and just use normal concrete.

You will need an access panel to the AAV. It is worth getting a Geberit frame on site so you know how it will all connect. We had some Grohe ones and the connections to the soil were not standard 110mm.

If you are tiling and using a flow screed you may be better using a cement based one as it does not require scraping and priming. Regarding deflection, this table gives maximum spans for different beam / block combinations: https://www.forterra.co.uk/bison-precast-concrete/beam-and-block-floors/load-span-tables-1 Once you are near to the maximum span you are likely to experience more deflection. 5 metres is really pushing it for a standard beam. The fatter beams are a struggle to move around.

Single skin 10 blocks per square metre, double skin 20 blocks per square metre. Deduct the areas of large openings, but don't bother about smaller ones.

Which warranty provider did you use? NHBC still state: "Alternatively, where the builder has demonstrated that the water table is permanently below the underside of the lowest floor slab, a Type B structurally integral concrete system is acceptable without further protection from a combined system." So if the water table cannot be guaranteed by an engineer they insist on type C.

Hi @Steve1 and welcome. It sounds like you know plenty. What construction type are you using? There are a few other members here from Bristol. They are not all mental.

And next time, hold back on the piss coloured grout!

The bounce is down to the beam and bearing spacings more than the screed. Where is the insulation going?

On a slight point of pedantry, I do not find it easy to understand technical terms and measurements but I find it even more confusing when I keep reading the wrong units. It is like frequently reading a misspelt word. kW is a measure of power. kWh is the measure of energy. It is the unit used by most energy companies. 1 kWh = 1 kW for 1 hour, 10kW for 6 minutes etc.

+1 to getting them cut and glued. Get them handed so they are layed the same way up. Sometimes the specials - like squints - come out a different colour and are more expensive.

Either will be fine but it is vital that the cavity is sealed and no air from the cavity can escape to outside. The top of the wall at loft level is the most vulnerable.

The cracks are fairly small and are probably cosmetic, although it looks like they have been painted over before. Have you had any work done that would cause them?

I did this several months ago. It actually makes his threads a more enjoyable read.

I am not slow to criticise architects but I think it would be really useful to have a designer spend a couple of hours resolving this properly as this is going to cost a lot of your money. As others have said, elevation and plan could be a lot better.

I am not in favour of buying goods from China. I think it is better morally and ethically to source locally made if possible. Also you can bask in your own smugness.

If the front gable was 1.5 - 2 metres narrower the eaves could be the same height as the rest of the house. Maybe you could increase the depth to make up for the loss of floor space if it does not involve too much of a compromise for you.