JohnMo

Hi update, house now built, just some cladding and slips to do outside - waiting on material. Ended up with triple glazing as suggested, made and installed by Wood Kraft in Elgin. Once the foundations were completed it took another 11 months before we were in. Spec Private water with our own borehole, mains gas, septic treatment plant. Triple glazed throughout MVHR Durisol walls, parge coated internally (sand, cement and lime mix) for airtightness, floor to wall junction with liquid airtightness paint, battons and plasterboard. External a mix of stone slips and Scottish larch. Posi rafter roof structure, battoned and counter battoned 100mm to give 350mm insulation space and then spray foam insulation. Passive House systems Reflective vapour airtightness layer, further battoned and plasterboard. Roof finished in slates and sarnafil EPDM standing seam and 3.1kw PV. Floor slab buildup, strip foundations with 100 to 150mm reinforced C34 concreted slab, 200mm of PIR insulation, UFH pipes throughout, at 300mm spacing, finished 100mm concrete with 70mm insulated perimeter. Work completed by myself Floor insulation UFH All plumbing except gas Durisol block work All battons to wall and roof Internal stud walls Parge coat Vapour control on roof internals (all ceilings match roof line) PV install, except electrical hook up Installed all bathroom s (x3) External cladding and currently doing stone slips. MVHR install Project managing and organising sub contractors who completed - ground work, roof structure, sarnafil and slates, electrical, windows, joiner for plasterboard and second fix joinery, taper for plasterboard. Images are a before and after

Take it you are in Scotland, I fitted GSE trays, tried to follow the instructions and they made little of no sense when working with sarking boards. If you add additional timber on the sarking the finished roof looks rubbish as nothing aligns correctly with the slates/tiles. The additional ventilation gives you a little uplift in performance, but not much to worry about. Screw them direct to sarking boards and make life easy. I had metal flashing at top and sides, flex stuff at bottom.

I bought from insulation hub, came direct from factory delivered to my door, delivery at no cost (NE Scotland) 400m2 of 100mm thick.

Reply may be a little late, but could help others. Are you trying to design around the slip or the durisol? When you are doing the lintels with durisol the blocks are on the end, so 500mm high and 250mm wide. The blocks either side of the window/door opening are modified to take the rebar. The window or door heights can be easily made to suit the slips, with too much additional work. The door opening, by the white box is 2100mm high, the open under the flattish roof, lined up with the blocks at 2000mm, both opening require blocks to be modified.

I chose an Atag A325ECX, it can take preheated water which increases the flow rate, have a thermal store upstream, cold water passes through the stores DHW Coil before going to combi. Store used as a buffer for UFH and has solar PV connected to immersion. So always sits at about 40 degrees. You can go open therm if you want, but have just removed and gone simple route, basic thermostats but with self balancing actuators on the UFH manifold and run UFH 24/7 at a low temp using a mixer and pump after the store.

It may be a bit late, but just commissioned a system similar to what you are looking at, here is what I have, after a few changes. Atag combi boiler, Telford thermal store (acting as a buffer with benefits) with boiler heating coil, DHW heating coil, mixing valve at outlet. Thermostat (middle of tank) set at 45 degrees, to reduce heat loss. UFH running at 30 degrees Solar PV Hook up, cold water to DHW coil, this passes through TS, and into combi, if it is hot or cold, the Atag boiler is designed to take pre heated water, so boiler doesn't care, the boiler only puts the energy it needs to the correct outlet temp. Upside, if preheated, you get great hot water flow. In the summer solar PV should do a lot of preheat. Have a secondary circuit, pump with simple timer at the out DHW outlet, so it can pick up hot water from TS coil or pass through the combi. Boiler was short cycling connected direct to UFH, so the UFH manifold now has mixer valve and pump added, this is connected direct to thermal store. Boiler connected direct to TS heating coil, boiler temp set at 50 degree. Advantages, boiler is always in condensing mode. Simple hook up, low standing losses as the tank is no hotter than 45 to 50 degrees.

That's good to know, we should get our first real prices this week.

Hi all Planning a new build in sunny Scotland, semi passivhaus, just wait for the warrant to be approved. There bed bungalow facing south west looking over a loch. House spec, floor, walls and roof U value of 0.1. Double glazed U value 1.2. UFH throughout. 3.2 kW solar PV, with immersion diverting. Thermal store heated by PV only to provide preheated water to Atag Combi boiler with full weather compensation. MVHR. Air tightness looking for around 1 m3/m2. Did the maths looking at payback for triple glazing and got pay back periods of around 40 years. Due to the low heat demand.