Conor

If you switch to LVT or SRC (5mm) then you've room for 100mm PIR and 45mm liquid screed. Not ideal, but enough.

Works out double the cost of EPS, and about the same as PIR. We have 175m² to do, lots of steel beams and uneven slabs. Would have take ages to get right and didn't have much room for error.

Sorry, images in no particular order forst one is the pour of the final liquid screed on top of the TLA/polythene and UFH. The TLA. It's soft enough for about three days. After that, it gets a bit too hard to staple. The TLA goes straight onto the slab.

We used clip tracks, but you still need to staple the bends and any narrow buts where you can't get the tracks down. Plus the tracks themselves need to be stapled down as the will just lift the polythene of stuck down. We ended up hammering in the staples with a rubber mallet. Not as bad as it sounds!!!

We used the TLA and it was grand. Hell of a lot easier than laying PIR boards, and similar cost. Basically zero prep other than clearing the floors and shuttering voids. They did both our floors in a day. We used alpha screed, very good. Stapling in the UFH clips was difficult enough, our stapler couldn't cope with it. But if you have a contractor doing that, then not your problem...

You're over thinking it. Pick the board you like the look of, and set your thresholds accordingly. You'll likely never resand and treat the floor. Make sure your screed/concrete is well dry and heating on before laying.

Metal

We did 100mm spacing in hallway as couldn't get great coverage due to pipes heading across it, staircase, matwell etc so had to make most of space available

Wunda. Make sure you can put plenty of insulation under your floors before choosing UFH.

Do what @JohnMo suggests and take the list to Screwfix and ask them to price it up. Go in and open up a trade account (they'll give you one no bother with that sort of order) and you'll get another 10% off the order.

Oversize everything. Use attenuators at the unit and use vibration eliminating couplers (leather or rubber) at the unit. Mineral wool insualtion around the ducts.

Just drop in a service void at the ridge. 200mm should be more than enough. Run the ducts along the ridge and then down a service cavity to the manifold. This is ours. Still have 3.4m ceilings. We had to have one anyway to cover over the ridge beam.

They won't install anything you need your electrician to get the rcbo, earth, meter tails etc. They'll have a spec document somewhere in your connection agreement. For the caravan, 16a commando sockets are perfect.

You need a light guage DPM right to the edges and taped down. No need to go up the walls. Then edge insualtion around the perimeter. We got the screed company to do this and the guy stapled the insulation to the walls.

Vent axia are a popular choice here and haven't heard that many issues. I've gone for Salda Smarty units, which are half the price again, but not commissioned yet so can't comment on performance. But two of them were half the price of a single Zehnder... So if they are dung, it's not a disaster.

It varies from sector to sector and locality to locality. Here's my knowledge from the water industry. I've worked with various companies across the UK. The utility company normally have something like a new connections team. This team receives all new development details. The first job is to model and understand the impact the development will have on the network. A small development connecting to a major trunk network fed from a new treatment works will have no impact and the developer will just have to cover the connection costs. Infrastructure is designed and built with a lifespan and capacity that takes into account models population growth. Issue is old infra hits capacity at some point. Then, if a development will mean a network can't provide a reliable service, then alternative designs and proposals are looked at. This could mean a longer pipe to connect to a different main, upgrading a pumping station. In this case, the developer would be expected to pay for a portion of the works (this is where it varies, in NI there is a min and max limit) before being connected. A developer near me was not allowed to connect their surface water system to the combined sewer as the local plant is at capacity (there's a filar whiff in the air during heat rain periods) so they had to lay their own pipe system to a suitable discharge point (river in our back garden!). Of course they were 100% liable for these costs. There are also various other local taxes and levies that are separate and monies here go to general funds, don't know anything about that.

Looked in to it but discounted as cost comes in above precast slabs. Also, spans aren't nearly as good as precast (precast use tensioned cables) Precast slabs are installed in less than a day, you just need to get them measured up and ordered in good time.

I'd form the steps from concrete then just pave over with whatever paver you want. Can can then use two or more pavers for each step if you cant get what you want as a single 990mm slab. This is what we'll be doing and using 400 or 500mm quartz slabs as they are good value and easy to handle and lay

Percelain is also very hard on little heads ?

We originally wanted engineered timber floors and have set our door thresholds, kitchen gables etc 20mm above the screed. The reality of a young child and all the water, mud, stones, and generall abuse that comes with it, has changed our minds to laminate. Most seem to he 8-12mm thick, some 14mm. We'd need to get a total thickness of 18mm or else we'll be off at our front door and bi-folds. 5mm wood fibre would get us close if we went for 14mm laminate. Could this be double up if we went for a thinner laminate? Or would it be too soft? https://www.diy.com/departments/diall-5mm-wood-fibre-laminate-solid-wood-flooring-underlay-panels-pack-of-15/1520621_BQ.prd (Above as an example only)

It's all about the detail. Eliminating cold bridges, wind tight and airtight junctions etc There's a lot more to the passive House standard, you need to look very carefully at window sizes and orientation, the orientation and shape / complexity of the structire. .this should be the job of the architect as needs to be designed in from the very start. You can of course just increase the amount of insualtion and get 90% of the way there... I don't know how feasible it would be to get another designer involved in something that's already designed. An SE won't generally know or care about the standards as it's a separate part of the design. Regarding an engineer with ICF experience, not needed. And ICF house is just a nomael reinforced concrete structure and every SE in the land should know how to work with that.... I can highly recommend ICF. There's just less to worry about. Cold bridges are largely eliminated (or can be) and airtightness is simple. As we did was tape around the windows and wallplate junction. The whole house is just the right temperature, and it's super quiet, and feels solid We went for an extra 100mm insualtion on the outside (so 250mm in total). We're in the house 3 weeks now with just a couple fan heaters going and the house is a constant comfortable temperature. Go for it.

Seems well covered but I've done a few recently. 15mm tee. Short length of copper pipe and one of these valves.

We've just had our house finished in Sto. It's fantastic.

No reason why you can't get a large zinc or powder coated aluminium flashing made the full depth of the fascia to replace the standard grp drip detail.

If it's a small area a solo surveyor should get it done in half a day and a basic drawing knocked up for a couple hundred quid.