tonyshouse

I think that you may well need planning permission for PV panels on a garage

It is called belt and braces, the evidence is there for not needing to do this, North America and I did see a paper that referenced constant 50 C doing sufficient sterilisation against Legionella.

I like fail safe

OSB is not dimensionally stable, it can expand if it gets damp. why use plasterboard at all, that doesn’t like getting damp either.

Nearly all of North America and Canada set at 50C, I have been keeping mine at 50C most of my life lower the better as less heat loss, you don’t want extra heat in the house if we get a summer.

Design out thermal bridges, design in insulation, ducts MVHR, solar, shading

I would start with target u-values, for me less than 0.1 for walls, floor and ceilings 0.7 for windows you may then find that you can design out heating, heating bills, servicing costs, repair costs replacement costs 1, Gshp better cop, 2 good idea, 3, 4 &5 pass

Between the beam and wall or between beam and block and sub structure?

Is it rain or condensation?

I like to sit the window board on the ledge formed by the top of the back of the sill like to fill the cavity with platinum EPS beads like biscuit joints in the mitres, love gorilla glue and packing to perfect position weighting it all in place and foaming in all the gaps

How many doors to get to outside?

Yes but it shouldn’t be, windows often on packers should get sealant on the outside as a minimum door sills should not be unsupported

I wouldn’t but you can, we will never know

Mortar for me

Or diagonal noggins under where the battens land