Conor

If you can source a 125mm bit, it will be a lot easier than a 152mm. I drilled half a dozen of these through 150mm thick reinforced concrete slabs with an SDS max drill. Would not reccomend. Used pros for the 200mm holes for the 4x MVHR ducts.

No, you normally run in DHW priority. I.e. if you've your heating set to 24x7, it will switch to heat the hot water tank when temp drops below setpoint, then switch back to heating.

He should and know all this, if he doesn't then he's not up to the job. Has he discussed any of these with you? As the client / owner you'll need to sort your own insurance.

You're still at the initial curing stages, you don't want to add heat for another two to three weeks minimum. Just keep windows open, don't rush it.

That's water ingress, not just damp. My money is on a bodged uPVC door installation or a new patio / surface above the dpc with no perimeter drainage.

If you hit the passive house specs and actually achieve the required performance, you need little or no additional heating input. That however is based on a load of assumptions and conditions around occupancy, habits and environment. Away on hols for a week in the winter? Your house will be freezing when you get back. Seldom used North facing box bedroom? It'll be chilly most of the winter. Our architect specialises in passive house designs and told us he'd never spec a house without some sort of supplementary heating. In reality, a couple towel rads and a storage heater or two will be all you need. We're almost passive house standard (meet all the U value requirements, MVHR is certified but we're short on air tightness) and there no way we'd be without our underfloor heating. During the cold snap last Dec, it was on almost constantly.

How long is your screed down? Don't want to dry it too fast! Good ventilation / or dehumidifiers work wonders.

Turn heating on full temp, use your hand on the bare concrete or a cheap infrared thermometer.

We put a dedicated loop in to our larder/store... purely for cooling in the summer if it was ever needed.

yeah, 50mm isover acoustic is what we did.

I'd use an offcut of basement wall capillary board - the dimpled plastic stuff that you put up against a tanked wall to prevent damage. I'm sure somebody on here will have a square metre sitting around somewhere. It will stop damage to the PIR and also direct water away.

We used stairplan, seem midway between stairbox and a fully handmade carpenter job. All very positive, even though they couldn't deliver to NI and I had to travel over in a hire van to collect.

Is the roof built yet? If not you can use GSE in-roof trays and put panels in right from ridge to gutter and valley to verge.

Sounds like you've really thought about this and happy to take on suggestions. Re the burners. The house you are about to build will be far more airtight and insualted that the one you built 17 years ago. It's a different way of living and thinking about heating. You're talking anywhere upto £10k for those two burners. That's an expensive backup plan! At no point have we regretted not putting a burner in our icf house. I can imagine how uncomfortably hot it would get! We have three 3kW blow heaters as emergency backups if the ASHP goes down. And in reality, it would be 2-3days of no electric before we got in to difficulty. If you spec everything right, your build will only lose 1-2c every 24hrs in the depths of winter if your heating is off.

If it were me, I'd put in a mix of black and white beach / river pebbles. On top of something rigid to protect the PIR.

I have ours set to heat in off-peak only, 5c offset, 45c target. We shower in the mornings so no real issue if the temp drops off in the evening. At the weekends this often isn't enough (my parents stay with us most weekends) so I have it set to come in anytime before 6pm. With a heatpump you want it coming on as few times as possible, but for as long as needed.

Well done on getting planning in just 10 months! Agree, with most of what John says. A fire, never mind two, has no place in a modern ICF home. Kitchen appears to be open to the rest of the house. You'll need some way of closing this off to satisfy building regs. You'll need to pull the stairs back or move the wall with the lounge forward to accommodate this. Roof angle looks low - less than 30degrees? Can you lift the ridge height a bit? This will match the style of the build better and give you more room upstairs. I'm guessing the design brief has lead the design to be centred around the occupancy of just two people? The room layout upstairs will put potential buyers off if you were ever to sell - and lack of a proper second and third bedrooms will affect valuations for mortgage purposes. Does the craft room and second bedroom have escape windows? If they are via skylights they need to be quite low. You've mentioned a celling height of 1.5m in the eaves, which is too high for escape windows. Upstairs landing/hall is dark and pokey - doesn't look like any natural light, unless I'm missing a skylight? That whole master suite needs a good rethink. You have the room for a generous ES. We have a 2.5x3m one with full walk in shower and double sink vanity. It's fantastic. Don't scrimp here as it's the bathroom you'll use the most. The RHS end of the wardrobe room looks either to small to use as a space and too big for a wardrobe. I'd pull the wall forward and give the space to the store (poss laundry room.) Where is your hot water cylinder going? If in the "boiler room" (who uses that term these days?) then it's as far away as possible from your main shower! Consider washing machine/laundry upstairs and ditch the awkward GF utility. We have ours upstairs and it's waaaay handier. Ground floor looks pretty good - I don't think the lounge is too small. Nice big larder - good call. Are you set on a vaulted ceiling for the kitchen diner? Missing out on another bedroom upstairs. is the garage part of the thermal envelope? Hard to tell from the drawing as all walls shown as the same. Regret I have is not including an integrated garage in our build. FYI you'll have to have the FFL of the garage 150mm below the FFL of the house. Heating/ ventilation strategy etc?

Use 2x45s and create a void at the juncture between room #1 and room #2 if required. We had to do this but luckily all hidden above kitchen units, just built a bulkhead above right to the ceiling. What's your floor structure and do you have a suspended ceiling for services?

Ok, first things first. Do you need to replace the entire roof and raise it?! Or do you mean ceiling? Why can't you just fire in 400mm of loft insulation? Some photos will help.

A 40m duct run will require some very large diameter ducts. MVHR might not be the right option. I've two units due to the layout and size of our house. In hindsight would have preferred a single unit and compromised on dropping a ceiling or two to take the extra ducts.

Basic 1:2:3 mix would do the job (roughly 20n.) It's probably only a couple mixers worth.

This means it's a public sewer under ownership of the local water company. So not your responsibility, and more importantly needs to be accessible for maintenance - which it won't be if you put a deck over it. On the subject of smell, you shouldn't really get smells from a MH like that, even if not perfectly sealed- if you're needing to use silicone to to stop this, then there is another issue going on that might need to be addressed (poss. downstream blockage.) Up to you if you want to bother the water co. Somethings best left alone.

Outdoor acrylic sealant (aka window frame sealant). I wired up the fitting then filled the conduit hole with sealant and fitted the light etc.

We 3ant3s to do this but the kitchen maker really reccomended not to. Said it looks flat and the surfaces flget scratched and grubby. We went with oak effect that was close to our flooring and love it. Need the contrast.

When they drop off the new slabs, make sure you set them alongside your other ones to make sure there is no big difference in shade. We had two separate orders and the second batch were noticeably darker than the first.