JohnMo

Voulted ceilings depend on the design, our lounge is voulted, to be non voulted I would have to install a ceiling, so that is a cost adder, we are in a bungalow, so the loft would be huge and mostly a waste of space. With the voulted ceiling the airtight aspects were easy also. In fact all the ceilings match the roof line, it made the build simple

I would make appointments with a couple of local architects, I wouldn't bother if they are or aren't passivhaus experienced, unless you want it certified. Get a design your happy with, number of bedrooms, living space etc, then work on the thermal aspects. And also how you plan to build, method and if self build, turnkey, main contractor, or sub contractors under your control Decide early if you going single storey or two storey. I would say "fairly involved in project management", may not work for you or who is project managing, as you will end up stepping on each others toes. I would either project manage or let someone else. To project manage you need to be there a large amount of time. It may also depend on how you are building, turnkey, they may not even allow you on site without an appointment?

I wouldn't like to embed copper pipes as you say with joints, Pert-al-Pert or similar would be better, a manifold would be easy enough. You could almost run it like UFH, but with radiators. Assume the upstairs will be bedrooms, do you like the same temperatures in your bedrooms? A thermostat in each bedroom, would enable you run slightly cooler temps in one or more rooms.

I used a brush and shovel, don't overthink it

I added until I had a double cream thickness

Big gaps, sand cement. I did a parge with a thin cement mix, for this I used 3 sand (not sharp sand as it's too gritty), 1 cement, and about 1/5 lime. Applied with a broom.

You have air in the loops, from the sounds of it, UFH should be near silent

Thinking about it, under screed pipes they have to be installed in such a way that makes it possible to replace; hence the conduit. If you have joint below the screed, it cannot be replaced, so will not comply with Building Regs

Not greyed so far, overhangs were mostly completed in March, the rest finished in August, will get the last bits completed in the next couple of weeks. It wasn't kiln dried.

It's shiplap, I think

It came from Timber Central in Nairn

I bought a few bits from them, where the prices were ok and prior to that got a full installation cost, hence going DIY.

Going to be doing a UV protection to keep colour. Just need to find the time

I am due an invoice, was expecting it today, so should be here tomorrow, will let you know the final cost. I got from Timber Central in Nairn, they are on Facebook and that number is correct, the Google number is an old number.

Not sure what he drinks, but talks a by product of food

The guy that did my foundation block work, said I wasting my time insulating the floor and foundations as heat only rose upwards, just couldn't comprehend it went downwards and sideway

Why not Scottish larch, lower shipping costs, buy straight from the mill, much more stable prices.

Semi flexible is quite flexible. BRE do some design guidance notes also. Flexible duct is supposed to be pulled tight, but I wouldn't waste my time or money, to do it correctly is hard, so in a lot of cases, it's just installed badly. As said mix and match manufacturers, you don't need smart control, humidity control can be hit or miss as our humidity fluctuates greatly across seasons. Simple boost switch in wet rooms and kitchen.

Also worth considering are Coanda effect outlet nozzle, these throw the air several metres, so across a room, clinging to ceiling. This gives more flexibility for outlet positions

BPC Ventilation do a guide. Building regs will state flow rates you need to achieve. Ducting, metal or plastic stiff duct will need silencers between room to eliminate cross talk. Semi flex, connect via a plenum chamber and eliminate the cross talk. Don't go with flexible tube as the pressure loss is huge, so fan run at higher speed to compensate, making system use more electricity and make more noise. Passivhaus institute has some good reading material. The basic things I thought about, keep ducts short as possible, buy a bigger unit than you think you can get away with, as fan speed for a given output will be lower. Shop around. Read as much unbiased info as possible.

It not a CO2 alarm you need, it's a CO alarm.. very different, carbon monoxide is what kills you and produced by burning a fuel - CO2 is what you breathe out. In Scotland you need a CO2 monitor in the main bedroom, but don't think you need that in England. Interesting, Scotland regulations guidance note, specifically exclude the use of combined heat and smoke alarms, as heat alarm are only to be installed in kitchens. If the alarm is battery powered, the battery cannot be replaceable. CO alarms do not have to connect fire alarms.

I think the rules in Scotland and England are different, so where are you based?

If they see, they can take it, I had a motorcycle nicked, with a disc lock on, the bike was retrieved, and they had broken the disc to get the lock off. If you want a cheap shed - how about from pallets, then clad it wood or steel roofing sheets.

If you aluminium covered PIR insulation, you need to separate from concrete, as it forms it forms harmful gases. Aluminum reacts with the alkalis (OH) found in portland cement concrete. When these two chemicals are combined, the reaction produces hydrogen gas. This is why, when the reaction occurs in wet concrete, you'll notice tiny bubbles coming to the surface of a slab. Use a thin DPM to separate.