Iceverge

This doesn't seem to make much sense. Did you mean 150mm?

You'll need to seal them for the test. Either cap them or put a plastic bag over the top and seal with tape temporarily. You're unlightly to cause any damage IMO.

Defo not. The outside leaf will be cold and possibly wet for much of the year. Any ply here wouldn't last the battle. I'm not sure about the gap there.

They'll work fine for the depressurisation side of the test. They'll let a gale blow thorough for the pressurisation part.

Should work fine if the nylon is strong enough. Green building store used compacfoam. https://www.greenbuildingstore.co.uk/kirkburton-passivhaus-strategy-for-windows-overheating/ What kind of windows are you using? The worst heat loss in our house is through the window frames. I would have liked to have overinsulated the frames if I could have easily done so.

Our windows rested on the external concrete cill and were bolted to the outer leaf. Our 18mm OSB boxes didn't actually take any weight of the window but are quite strong so long as the window isn't too wide. I'd be slightly weary of having a cold metal bracket on the external leaf connecting to plywood. It'd be inviting condensation on the ply in my mind.

Yes. Lift floor boards. Drape a breather membrane between the joists, tape diligently to all walls. Fill with batt insulation. Airtight membrane over the top. Replace floorboards. Don't worry too much about getting extremely low U values. The windtightness (breather membrane) and Airtightness ( airtight membrane) will stop the bulk of the heat losses.

Plenty of electricity poles > 50 years old surviving just fine. Mind you the intensity of creasote treatment would give you sunburn.

Derisk your build by using masonry or stick build timberframe. Theres been a a few to many stories of people's projects being sunk here recently by relying on ICF companies or TF manafactuers that went bust. Also ability to drive 5 mins to your hairy knuckled local builders merchant with a car trailer and return with a few 9X2's, 2 dozen breeze blocks, a bag of cement and a box of nails is invaluable in the real world of building a house and saves lots of time and cash.

Tackle that suspended floor would be the first port of call IMO.

Can you post a full screen shot of the drawing ( without personal details) I'm unsure as to the total design and where you intend to make savings? At the moment your rafters are pressing down on the wall and Steel I Beam at the apex (BLUE) They are pressing up ( RED) and in turn transferring the load to the foundations via the walls. I assume the I beam is supported by pillars or the gable walls. It's pretty normal and allows your chippies to use off the shelf timbers and I can't see it as a very expensive solution. The Ecojoists ( metal space joists- pozi joists) for the floor of the upstairs won't really have much effect of the roof AFAIK. Attic trusses won't work unless you are prepared to loose some internal space from the rooms for bracing as well as at the apex. An elegant solution might be a scissors (vaulted) type truss. You'll still get a vaulted ceiling but your internal pitch won't be the same as the external. You can do away with the ridge beam then. Excuse the ropy drawings. Here's one from the internet.

SS steel ones from Vartry Engineering weren't too bad. I can't remember exactly.

It wouldn't matter as they would be entirely inside the heated envelope or outside of it.

Solid Joists? If so i would expect resilient bars are a must. Also you get a nice 16mm service cavity for your wires rather than drilling.

Why not separate lintels? Better thermally than catnics and as cheap as chips. Precast concrete lintels for our house were about €25inc VAT per window.

I don't know on the new build if the window overlaps the cavity closer. Worse case it is like this and the installers haven't done it. The cold outer leaf could be practically "touching" the inside which is a bad thermal bridge. I suspect in reality they've moved the windows more inboard and this isn't an issue. However it's still better to cover as much of the frame as practical with some insulation. However you'll need to drill a 25mm Diameter through the membrane and batten as shown in each of the four sides of the window to allow your EPS beads installer to give a quick squirt of beads to thermally isolate the windows. If you want you can drill a few extra holes in the batten only and not the membrane to visually check that it has filled to the corners (it will BTW). The Hole in the membrane can be very simply patched afterwards with a piece of A/T tape. Hey presto. A fully thermally insulated window frame. ZERO waste of insulation unlike boards products. A fully gapless install No thermal looping/bypass. Perfect A/T details. Exactly consistent frame gaps unlike other methods. A consistent pallet of very cheap materials. No need to fight with the window installers. Don't worry, almost all of us are in the same boat.

There's plenty of space to over insulated the frames internally there. I wouldn't sweat about it. In the existing house here is what you have. @Dave Jones is right it's a nasty thermal bridge. However it's easily solved. This will do for the heads and reveals. 1. A/T tape and membrane. 2. J bead. 3. Batten shimmed level with j bead. 4. Membrane returned to inner wall and sealed. 5. Plasterboard. 6. EPS beads injected into wall as insulation. For the Window board you'll need to run some support in the form of a few battens per window as below shown inn yellow. These should be fixed to the inner blockwork. 3- 4 should be fine. Then let the EPS beads Fill the rest. You could mess around with PIR boards etc but it's a mess. Just let the beads do the work.

For the DHW I would just run some 15mm pipe in the duct. So long as it's below the frost depth and there's not a gale of cold air blowing through the duct it should be fine uninsulated. The wait for hot water would be very small even at 16m. Say a 10l/min shower pulling 5l/min hot water would use about 1m of the water in the pipe per second so 16m would be about 16 seconds plus any dead volume in the shower body.

It looks like sand and cement. Problem is caused by the usual culprit, water. I would just mix up a bucket at 4:1 and patch it in. Sponge it after to match the finish. When it's well dried in a good dark coloured exterior paint should be enough to protect it from water running down the wall from above. If this isn't enough carefully cut the paving back 100mm with a diamond disc and dig it out 100mm deep. Then back fill with chippings to match the paving creating a mini french drain that will prevent any rain splashes and mini pools of water by the base of the wall. I think sand and cement patchs and a good coat of weathershield will be fine however.

For info, the above method works well without cavity closers for EPS blown beads, getting a really consistent and easy and cheap to install well insulated window. You can even pre install the membrane, tape and J beads before the window is in situ.

I would. 1. Parge the walls. 2. Cut a strip of membrane the length of the perimeter of the window and about 50mm deeper than the reveal depth. 3. Starting at the 6 O'Clock position lay the membrane on the sill, up the reveal, across the top, down the reveal and back to the 6 o clock position. Use some dabs of silicone to hold it in place. Be sure to push it well into the corners. 4. Careful mark 10mm (or more depending on your window design) with a pencil around the perimeter of the window and apply your split airtight tape to seal the window to the membrane. 5. Fold the 50mm remaining piece of the A/T membrane onto the wall and apply a double bead of airtight mastic to seal it to the parge coat. It may need some cutting and trimming at the corners. 6. Screw a J bead to carefully cover the edge of the A/T tape on the window perimeter. 7. Slot in plasterboard with a few dabs on the reverse and mechanically fix through the membrane to the brick reveals. Squirt some Illbruck FM330 behind there if you're anxious about any hollowness. You may need to use some small packers to get perfectly consistent reveals. I would avoid paint on airtighess near windows. You are lightly to spend longer masking it neatly than using actual airtight tape and it doesn't adhere as well either.

Drill 10mm into the wall free hand. Then put the block in place and with 2x normal wood screws through it adjust them to push the block into level using a spirit level. Then finish drilling the hole correctly.

@ToughButterCup How about just drilling a block of timber first on the bench at 90deg and using it as a guide to get the hole started.

A perimeter upstand of say 25mm PIR will reduce the conductive heat loss from the slab -> walls -> ground. I'd you're not bothered about this you can just pour to the walls.

Get a long (greater than the wall width) bit to make a pilot hole with a slight fall to the outside. This will ensure both holes line up. Drill a piece of 50mm timber with 2x holes 125mm apart. Make the middle one perpendicular to the timber and the outer one slightly angled outwards. Peg the pilot hole to one hole of the timber and use the other hole like a compass for your stitch drilling. It will ensure a neat circle that will be slightest bit conical towards the inside making it easier to chip out. Then get hammer and chisel and get tapping. This can be tedious. Now repeat from the inside. I had 3 holes through 215mm block, 250mm cavity and 100mm block to do. They took an hour each with a cheap SDS.