Conor

It's too close to the bend. Can you bring the small waste pipe through the I joist and connect in about 500mm down from the bend? My general rule is leaving 3-5x pipe diameters between connections, bends etc. Might need to do some reinforcing of the joist.

We just used an external double wall socket. SWA up from the bottom through glanded conduit, main house ring straight through the wall behind an existing internal socket. Tough enough getting everything fixed in to the terminals, but all worked.

Why is your inlet fan RPM higher than the exhaust RPM? Is there a part that shows the flow rates? Or pressure drop?

That's about £5k labour only, so £35-£40/m². Our 43m² patio, same flags, laid in a staggered bond, dust screed, loads of cuts, took 4 man days, with another 2 days of prep and drainage works before. They did have a digger to help drop the quarry dust in place. All in all, it's at least double you'd expect.

We had all our steels placed behind the insulation and steel plates welded to the bottoms / brackets fitted to take the loadings in question. This does two things, greatly reduces the crossectional area that heat can flow through, and allows you to fill the space with more insulation. All our steels bar a window corner post are behind 100mm PIR, and on the inside a layer of aerogel. The corner posts are similarly set back, with welded offset plates on each end to transfer the load. They are behind 50mm PIR and compact foam. With my IR thermometer, these areas are only about 1c cooler than the fully insulated walls. Takes time and effort to get things like this right, but worth it.

In a service void.

You could probably get away with just doing the couple metres or so as a hard surface.

You're all concrete? It's a balls tbh with all the drilling of clips and boring of holes for ducts. I didn't enjoy it, but I mad life harder for myself by using galv steel ducting.

No, just need to leave enough for door frame and architrave. You either want o leave a good 100mm of wall between architrave, or nothing.

Use a single lintel for the full span.

You'll be amazed at the widespread indifference to energy efficiency within the construction industry.

Just a couple follow ups. It's actually the groundwater where the heat is extracted from. The borehole needs to hit rock / gravel with decent movement of water. The deeper you go, the greater the water column you can use. The two 100mm boreholes close together, the same water in each strata will be cooled twice by the coolant. You need to make sure they are far enough apart. Then again, if you hit a decent karst at 10m then your sorted. Don't know until the drilling starts. Secondly, is the GSHP company reccomending this option or is it the driller? The driller has likely been subcontracted by the GSHP installer and you'll need to make sure they are happy with this option. Finally, just get an ASHP. Spend the spare £10k on a nicer kitchen and bathroom.

The issue there is that you'll be accessing a smaller "pool" of groundwater and might suffer from repletion issues. Out of interest how come ground source instead of air source? Don't hear of many being installed for domestic projects these days, don't normally compete in terms of cost.

Also known as selection bias. Stacking the deck etc. you're going to want a big a pot of examples as possible, along with statistics from the mortgage council on how many homes are actually built using this technique. And if you get, say, 15 randomly selected case studies from here or other sources, you can then do your own analysis and gain insights based on these studies. Let's say 15 cases, 2 had significant challenges, looks very different from 4 cases with two having issues.

We built an ICF house, no issues tho 😂

You'll get an equivalent blade from Amazon for about £20. I use trend and Saxton. https://amzn.eu/d/aZRIIIG

What about shading? Do you have trees nearby? If my panels weren't 2.5 stories high, and instead of a single story garden room, I'd be generating 0kwH at this time of year, rather than 5kWh, as they'd be in perpetual shade due to the trees around our site.

Is there flashing around chased in to the wall? The fibreglass does look really poor and I can see the joints between the boards underneath. These should be filled and double taped to prevent cracking. If your timber structure and deck aren't up to spec, then any roof system could fail.

We put in fire door and seals to the plant room, just because there's so much electrical stuff in there, if a fire were to start, it would be here.

In a conservation area, you can't normally have solar panels that are visible from the road. So if all on the back roof, you should be ok. We used GSE in roof trays, which was one of the reasons why we got approval to have 8 panels on gable return roof thats visible from the road (also conservation area.)

Good point about labour. However, doing something niche life precast panels or ICF, will reduce the potential pool of contractors even further. You want the right people for the job. Re build speed.. yes on paper it's faster, but I think a bigger factor in construction time is how good your builder is, how you package the works, and how organised you are. The method is secondary tbh. Our ICF guy buggered off on several occasions for days / weeks on end as he has two crews building six houses at the same time. So it took a full nine months to go from slab to roof ridge with the ICF. You could have a good, organised builder using block and brick that could have a shell up in three months. Oh, and the Internal works and second fixes take up approx 2/3 of the build time, while the slab /walls etc are about 1/3. We waited 6months for windows alone. Finally, keep it simple, don't reinvent the wheel. If I was building again, I'd probably do timber frame with block skin. Mainly for sustainability/ Carbon reasons, but also it's what the industry does here, and there's better availability of skills and knowledge.

Its because there is no escape route for the first floor, as the ground floor is a single room, it effectively means all the rooms on the first floor are a room within a room. You'll need to create a separate escape route (e.g. separating the stairs from the open area downstairs), other fire mitigation system (sprinklers) or as BC has said a refuge area, which you cant provide.

As a neostat owner, I feel your pain. Horrible system. You'll need to set each stat to holiday mode and set holiday temp by losing down the power button g and getting in to the control menu. I can't remember what the default holiday temp is.

I doubt that precast insualted panels are a standard construction method recognised by lenders and insurers. ICF can be hit and miss even though it's fairly common now. Explored any other options? Timber frame with block skin for example? For the floor spans you are talking you'll need some steel in there to take the spans, a 150mm hallowcore plank typically spans about 5-6m max. Have you spoken to an architect or SE yet? Don't get stuck on details until you've the big stuff sorted.

I'd use concrete with small stones, just because it's cheaper and faster. I'm sure you've some insualtion to slot in first then foam in to place.