tonyshouse

Bit untidy but typical I am afraid

Option one is fine

There should both an insulation barrier and an airtightness layer in the construction and these should be all joined up. Sadly rare to find gaps between tiles should not cause cold draughts inside the house, the air tightness barrier should stop those. Insulation is generally poor for dormer windows and there are lots of places where it needs to be all joined up Are your eaves cupboards inside or outside the insulation barrier?

Copper wire works nicely too. Can be tied round the corners of the slate, near invisibly two loop with four tails two going to each side then twisted to perfect

Sand blinding is dangerous , it can later percolate into the hardcore leaving a void I like insulation under the concrete = greater comfort, slower temperature swings and the more the merrier with insulation

Lay a 9mm bed of mortar then plain roof tiles 14mm, then another bed of mortar then the block

Nice

Undercloaks drag water into the verge, looks like a bit of wind uplift to me too

Best place for them, must be a good architect too

What is the airtight paint doing?

I think concrete lintels on the outside skin would be ok though I would prefer to see 140mm ones rather than 65mm ones, on the inner skin where concrete planks are bearing on them definitely steel beams or channels every time need to keep wind out of hollow cores especially cross draughts. Tony tray does it bit I foam filled the ends too. service holes should not be core drilled out but designed and performed in !

More likely engineer would want steel beam, SJ, channel etc to protect their PI insurance

It is not a problem, the level will rise and fall naturally but won’t do any damage so long as it does not freeze, lots of people have it without realising it.

Vapour barrier on the warm side of the insulation

Best NOT to have a vapour barrier or impervious layer on the cold side of the insulation, MDF is prone to swell and change dimensions irreversibly if it gets damp

My cavity is 305mm wide fully filled with R32 fibreglass batts, separate lintels to mitigate the usual thermal bridging issues

In Alberta in Canada there is a small estate of homes that solar thermal store energy from summer to winter and it provides all hot water and heating and it is -30C in the winter there too, should be very easy for us dlsc.ca

No! It will dry out as the house is warmer than the ground, moisture will be pressed away due to differences in partial vapour pressures and will become bone dry after a year

Looks nice, sand when dry flows like a liquid, like in an hour glass

Blinding error!, the sand percolates through your hardcore and leaves a void! I have seen slabs sink as a result then there is the thought that vapour barrier should go on the warm side of the insulation so I put dpm on top of the insulation - unlikely but the dpm could pick up condensation on the top or inside and sweat ?

Any stock brick (frost resistant) will do the job.

Most such methods result in colanders, very draughty and huge heat losses - beware

We plaster should be ok , need to hermetically seal to adjoining air tightness layers , need to eliminate air ingress round joists and in any first floor void and any penetrations

Periscope vents, and you don’t need lintel over an air brick

Normal in cold weather, should go during the day, likely no vapour barrier on ceiling and some air leakage from the house into the loft making it worse than it might be.