Conor

This is what we ended up with from our SE as a passive slab has it's limits (also on good ground, firm red clay). We are an ICF basement with 1.5 stories above. We abandoned the passive slab idea as we were exceeding the limits of what EPS and a simple slab can do. Ended up with a 200mm ground bearing slab with two layers of mesh with a 300mm x 600mm ring beam with extra rebar. Worked out a lot simpler and cheaper than a passive slab with the extra footings and higher grade EPS that would have been required. As we are using ICF directly off the slab and 200mm floor insulation, there's no cold bridging and it's well insulated. Passive slab is great if you have a light building, not so much it's it's a big heavy building like ours.

Objections are meaningless unless they are directly relating to actual planning policies... e.g. if ina conservation area, pointing out that the design does not meet the design criteria is valid, but writing in and saying you don't like the look of a design is meaningless. If you have a contemporary design in a largely "traditional" (what does that even mean?!) area, then it will be likely the planners will be expecting something of "outstanding architectural design (to quote our local planning policy). That of course, is completely down to the subjective interpretation of the planning officer. We did a modest bungalow type design, but with modern design styles ( large windows, timber cladding etc), the local heritage and monuments people listed 10 objections, none were sustained by the planner as they were all subjective design preferences (e.g. she wanted timber window frames) not linked specifically to the planning policy. Conversely, neighbours across the road put in an application. There was a single objection, but it was very detailed and referenced specfic parts of the design that were not aligned with the planning policy. I'll be majorly pissed off if they get though planning as we deliberately avoided anything that was against the design guide and we've ended up with quite an ordinary design as we thought we'd never get the likes of flat roofs, zinc cladding etc through.

@StonesWhat screws/washers did you use to fix the 100mm insulation sheets to the plastic webs? I'm assuming I'll need stainless as I'll be rendering over.

We are building using Amvic Platinum 300mm blocks - U value 0.2. We want to get down to ~0.15 and the agreed solution with the builder was 25mm celotex on the inside of the external walls to get to 0.16 before finishes. I'm now rethinking this and adding 50mm external EPS will get us to 0.15. Reason for this change of heart is that we have concrete floor slabs resting on various parts of the walls, so we've lost the inner 75mm EPS layer in several places around the building, plus some rooms are already on the small side and could do with that extra 25mm. Anyway, I remember reading a blog where somebody fixed extra insulation to their ICF but I can't find it. How would you do it? Expanding foam and screws? How many per sheet?

You also have a mouse problem.

May as well add it, and if it's over a certain size or habitable space, you'll need building control anyway.

Spray it. Kill it. Seed it.

No. You could cheat the test by blocking the chimney, but in reality you'll just have a massive draft in the house and lose way more heat than an open fire would contribute. (I'm getting slightly militant about fires in new builds...)

My architect has specified 50mm service void in the vaulted ceilings - void between insulation/membrane and plasterboard achieved with 50x50mm batons. I don't think that's anything to do with regs, but more of a practical minimum.

Nice one. Well done. Complete demolish and rebuild I assume? Where in the Lakes' are you? Many here have used Sunamp so I'm sure you'll get loads of advice.

Please do @dpmiller

That's the thing, after the ICF contractor is done, I'm then acting as principle contractor and will be directly employing and contracting people that will be using the scaffolding... so going to go down the certified route. So far the ICF contractor has been doing his own kwik stage on the inside of the house for each pour... it's ropey as hell and no way I'm going down that route for the main scaffolding. I'll allow 8-12 weeks then.

We'll need scaffolding on site in about 6 weeks time after the ICF is finished. Only needs to be up long enough to slate the roof (thermohouse panels being installed without scaffolding) and do rain ware, PV panels and skylights, and render. So thinking about 4 weeks. Building perimeter is about 45m, 1.5 story. Buy second hand and have erected or just hire from likes of GBS? Anybody idea of costs for hire or purchase second and? To be honest, speed and less hassle are bigger factors than cost.

I think the cost is comparable - if you compare by performance levels . I.e. a standard ICF build will outperform a standard block build in terms of insulation, airtightness, strength etc. I.e. so you have to take in to account the extra insulation, airtightness measures, structural elements, cold bridge mitigation etc for a standard build. So don't be comparing a ICF system against a standard block cavity building with 100mm insualtion.

@Russdl sweet home 3d. Crude but very handy for playing around with room layouts and configurations. I roughly drew up our architects drawings in it. Meant we could tweak walls and rooms before going back to him to draw up. http://www.sweethome3d.com/

This makes more sense now. Ground level on the Eastern side where the MVHR is will be approx 1m below the ceiling height. Might have to think a bit more about that.

MVHR vents are meant to be on the wall at end of hallway by the rear door. But I'm not thinking about locating the MVHR in the play room and have the vents directly though that wall instead - could get better spacing there as well. OR even on the eastern wall by the ASHP - vents would have to be just above ground level tho. I'm planning on a pre-plummed cylinder if that helps? ASHP is only heating source in the house.

Was thinking that but the service void to the ground floor is basically at the corner of the cinema room/cold room/stairs walls - wanting to keep the pipe runs as short as possible for hot water. Actually, i could just run the 22mm pipe from the cylinder and have the hot water manifold further under the stairs?

Digger will have that scraped away in a couple hours. I'd let nature be until then. We strimmed and mowed our site almost monthly for over a year while we waited to start... complete waste of time.

Trying to figure our best location of our basement plant room. Originally was to be in the corner of the basement but we now want to use that space as an office. I'm hoping I can fit it - 300l cylinder, 60l buffer, UFH manifold and MVHR (tho this position is 2m or more from the external wall- so may locate separately) in the space under the stairs - basically a big cupboard with 2m bifolding door. Full head height area is approx 2m x 1m, with another 1m+ under the stairs that would not be of much use. Leaves the hallway approx 1.6m wide at the stairs - more than enough for a basement. There is a waste pipe for condensate nearby. Thoughts? Basement for context. Red paved courtyard is is at basement level, rest of walls are below ground.

This is good to know, I've still the new connection aspect to book in.

No idea. It blocks small leaks. I like to think it works like the movie Inner Space, where there a crew of people in a microscopic submarine floating around and patching holes.

We had a similar drop in our system, a bottle of Fernox F4 fixed it. (in fact I think the rate of loss was a bit more than yours). Suspected a small leak somewhere hidden in the floor.

Do you just have UFH in the ground floor or first as well? What thickness is your screed?

I had the same issue in regards to removing existing supply to the house and moving to a temporary kiosk - VAT was charged and there is no option to get it back as it's a service.