tonyshouse

Sorry, clutching at straws, unusual to get damage on internal skin, Where is the nearest radiator?

There must be a lintel, I suspect Catnic

What is in/behind/above that different coloured wall at the far end of the bottom pic?

I do floor first with semi non slip vinyl coved up walls 150mm and then wet wall 50mm downlap = failsafe

Looks like a water leak to me, gutter, overflow pipe- heating or water. the crystals will ne sodium nitrate (dissolve in water) could be wet getting into the wall, what is on the other side of the wall.

Yes, or false skeiling ceiling

Wood would do

Wall plate is straight and the distance to the top of every rafter including the hip rafter ha to be the same on the outside top corner of the plate. cheats over cut the birdsmouth a tad and adjust to perfect as the go in

Nice, for me the op has too little insulation in the eaves zone and almost none over the wall plate ?

One F = 1f

How will the wall insulation join with the roof/loft insulation?

I hate all aerated blocks and won’t use them, they crack far to easily. I prefer medium density recycled aggregate blocks 3.5N are. Ok 7N also available. nice to lay, nice to fix into - practically perfect in every way

I would say step up into the new bit or raise floor level. I would replace it in plastic , any manholes outdoors

Yes but coloured, it seems quite glassy to me, most likely to be local and probably as dug.

Particle size

Also think cover width, not actual width

Mix looks like with grey sand mix ratios 4:1 and 5:1 and 6:1 then when close to correct colour try 5.5 etc

Mix sand and cement using teaspoon dry, there are a few choices of local sand and darker or lighter cements, 4, 5 or 6 and 1then 4.5, 5.5 etc. Once it looks good dry mix wet. Put in airing cupboard shaped, and rubbed to dry, check match the next day

Needs a fall, I would want to see min 1:30, I like lead and it will need to be code 6 min, this determines the lengths of the bays. I would say it looks too narrow and too flat, mun exit width 180mm , this plus the min fall and steps at 50mm will mean it it gets quite wide

Not fail safe so best designed out

I prefer wider to deeper, ideally no organic under concrete 3 or 400mm should be ok for depth 600 wide stops it falling over 450 is ok too definitely no throwing stuff under the concrete please

I am worrying about draughts coming in through the beam and block floor ? and through the blockwork walls, could you beg or borrow a thermal imaging camera some local authority’s have then for loan. Or hire one. Check what is going on, where draughts are coming in.

What overall U value are you aiming at?

Block up fans/ fan ducts, i.e. try to make them air tight, window tv’s should be air tight when closed, I would foam them up permanently ? Best plan is get it ready the day before and get the biggest fan you can borrow and depressurise the building and go round listening and looking for infiltration, under window boards, under skirtings, behind archutraves, through sockets and light fittings, ducts, consumer unit pipes and wires, airing cbd, under bath, under thresholds. Rectify, reenergise fan and look again then do the test

Cut in a water bar, vertical metal strip that is recesses into the sill and into the window. what sill will the new window have? I have very nice European style folded ali sills with end caps