Dreadnaught

Just to add to your thoughts, I found the whole chapter on moisture control in the Passive House Handbook very helpful in understanding these issues. In that chapter, and for a sandwich layers of materials in, for example, a wall and from inside to outside the layers ideally need to have a progressively lower vapour permeability. It states that vapour permeability of the material on the outer surface should be 5x that of the internal surface as a rule of thumb. For example, wood fibre board is very vapour permeable and so well suited to being the outer layer. It also helpfully states "Moisture within the fabric of a building is the most common cause of building failure".

No, its not too late. But that would be to forego a plot in a location that arrives perhaps once a decade. Its location is that good. For me, its worth navigating the admittedly daunting set of complexities for that reason. Forgive me for not saying more about the location now. I will be happy to do so once the ink dries on the paperwork.

Yes, of highly contemporary design. Made Ground (0 - 2m or so) over river-terrace deposits (then 0.2 – 1.5m) to Gault clay (at 2 - 3 m total depth). Recommendation is for screw piles to a suspended slab over a sub-floor gap. I have no idea at present how I am going to have the passive-house levels of insulation in the floor. (Oh, and the plot is between flood zones 2 and 3. The full card deck of issues!)

There are big trees adjacent to the site (a Horse Chestnut Tree, a Plane Tree, two Beech Trees, all mature) and the neighbours kicked-up a fuss about each of them. Its a conservation zone in the middle of the city so all those trees effectively have TPOs. And more than half the site is a no-dig root-protection zone. I did say the site has all the constraints imaginable

Yes, would love one but planning again say no. Tree roots galore! I have the world's most difficult site. It has the full card deck of constraints.

Thanks @lizzie. That's really helpful to visualise. I suspect the vendor thinks of his 50cm as a concession and we will have to move our property back 70 cm too to get a gap of about 120 cm. I have to weigh-up whether that is a fair deal in the wider context. Thinking…

Good challenge. Hmm, some more thought is needed. Thank you all. That has been very helpful!

I worry more about the construction phase. Can I build a timber frame house (single floor) so close to a boundary, with just a 50 cm gap? Also, does anyone know of any planning principles about how close a new build can be to a boundary? I have heard of a 1.2m figure mentioned, but I am not sure if that's just a guideline or whether its a requirement.

Sadly, planning wont allow it. No flue. Could be rainwater pipes.

Not sure yet. Architect has not done their work. No windows on that side, just roof windows (which hopefully would be > 1m from the boundary as the crow flies). Could do. But swings and roundabouts. Its part of a wider deal.

The fence will be the responsibility of the neighbour. Regarding maintaining my wall, I imagine it would mean squeezing in the 50cm gap. Is that too little? Its a single floor (bungalow) but good point about ladders for cleaning the roof windows on that side. It could be, but I have a tiny plot so keen to use it all.

This will be a new build bungalow. I am negotiating boundaries on my plot with the vendor. He is proposing to provide a little extra space to erect a fence beyond the outside wall of my future house (the boundary fence was missed off the plot as advertised). The construction method of my house will be timber frame, wooden I-beams (passive house) and rendered. He has suggested 0.5m (50cm) of gap between my outside wall and the fence (a fence that will be in place throughout the build). How much space does a contractor need to erect such a wall? Is 50 cm enough? What about scaffolding?

I'm amidst buying the plot.

Welcome on board! Great to have you here. I will be using a QS shorty for my pending build I expect.

Cat 5 and using a PoE access point for outside use. No need run a separate power cable. Here's an example: https://unifi-mesh.ubnt.com/#products

With the growing popularity of power-over-ethernet (PoE) devices in home automation, I am tempted for my build to install ethernet almost everywhere, and in some unusual locations, such as outside by the front gate, by the front door, where I can imagine having a car charge point, where I want blinds. PoE is now being used for lighting, security cameras, doorbells, and a host of internet-of-things (IoT) things. Who knows if this will bloom and become a ubiquitous standard but if you install the wiring at least you are ready if it does. Changing the subject, if your house is larger than can be covered by a single WiFi router then consider where two will go and give each location an ethernet socket. Buy specialist access points that offer seamless handover (such as UniFi by Ubiquiti) rather than consumer units (including the trendy mesh ones). Ethernet connections between access points is always superior to mesh. It is essential in my opinion that you buy access points that support seamless handover. Two low-end consumer routers will not work nearly as well. They hold on to the waning signal for far too long. UniFi units, for example, which are used widely in commercial installations, have seamless handover, are remarkably cheap, and are rock solid. They offer models for outside use too. Unifi APs do however take a little knowledge to set up but once done require no fiddling.

@Christine Walker good luck. I am sure there is a lot I/we can learn from you. Do share as much as you can on BH. Without hijacking this thread, I am particularly interested in your lessons learnt from your past builds and how you are using them in this one. I am also interested in the PM approach you are taking. And finally I am also interested in how your builder will interface with the frame company. All subjects relevant for me personally.

Welcome on board! As a dreamer, I was in your position a few months ago. Now I have an offer accepted on a plot.

I agree. Ethically dubious at best.

Nice. Out of interest, which company supplied the frame?

In my research, I have heard this said many times. Chippies over bricklayers for attention to detail and a pride in craftsmanship. Another issues I heard is about availability: good chippies are much easier to find than good bricklayers.

Wow, that's a good price. Might you be able to PM me their details?

I would be interested in your SunAmp quote. Andrew Bissell said on Twitter yesterday that prices had dropped recently, to about £1,000 for their most common model with average capacity, and excluding installation (which I imagine is DIY-able).

Out of interest, which timber-frame company did you use?

From the link in your first post. 2 Arrays… Tilt: 25.0°, Azimuth: 240°. The bigger one. Tilt: 25.0°, Azimuth: 150°. The smaller one. Should have read your first post more closely, haha!