MikeSharp01

Yep this will allow you yo keep warm in the upcoming ice age of course there might not be any power generation by then. Naturally ensuring you have a 10Kw supply will allow you to run on hell of a workshop / model railway / tanning salon / steel works / sound system / radio station in there until the time comes.

Yes it has perforations.

True if any water gets in there. If the breather membrane is outside it I am not sure how water can get there and any water that does will be dried out by the permiability of the structure will it not. As ever its the little details that frustrate. In the traditional case can water not get along between the two membranes if any splashes up there in a storm.

It is 40mm insulation but there 300mm on the inside and although it fixes to the 300mm sole plate that is split by 50mm of insulation ( the greeny / yellow lump) so it is well protected cold bridge wise. I do have a condensation worry but I figured that I could expect the whole mass of the trim to move slowley temp wise but I will review it again.

Thanks that is the traditional approach but I am not sure why - can you perhaps explain?

I need to now tidy up the DPM (Violet line) / DPC (Green line) on the outside of our frame. As I see it I have two options, see picture. I prefer the first (left hand) option as any splashing off the ground cannot get into the DPM/DPC as it is not accessible. Option 2 (right hand) feels more traditional but I am not sure it is as sound as the first in that the there seems to be a moisture path, by capillary action, between the two DPM/DPC layers. Any thoughts gratefully accepted as ever.

Quad glazed?

We didnt duct the ASHP pipes through the slab, felt like phaff, but decided to run them through and along inside the walls, timber I joists, so the insulation in the walls insulates the pipes.

And your definition of 'good' is....?

That is some serious windage.... I bet the foundations are humungus.

Sound advice - it is out of your control to all intents and purposes, you will have to await the outcome and the time will be better spent not worrying about it.

Looks good too, are the units handless?

Yes - I was refering to the case when there is no registered owner with the LR as was/is the case with the footpath next to our build. If there is a registered owner that is not you a new strategy will be needed.

Yes this is the case. If it is not being used you can fence it off and wait 8 (might be 10 can't exactly recall) years, then you need to put an ad in the London gazzette, or local equivalent, and say that if nothing is heard from the rightful owner in 2 years you will assume it is your land. Then if nothing is heard it is yours and you can register it. First thing to do is put a watch on the portion of land at the land registry. This will trigger a message to you if anyone does a search / enquiry at LR covering the parcel in question. Beware that the local foot paths officer might drift by or, as was the case last week with our path, a local volenteer comes by with a clip board and notes any issues with the path. If the path has a number then this will trigger regular reviews of it. You should also look at local planning to see if any covenants have been placed on the path. In our case a small estate was built on the road behind ours and the footpath ran between two of the properties. As part of the planning the council made an order that the footpath should be a minimum of 6' wide.

Welcome to THE forum for self builders.

This is the essential point about low energy home design in that function, how good it is at keeping the energy requirements down, has to go hand in hand with form otherwise you get a house that wont have low energy as its primary functional focus beyond being a machine fir living in. As I have said above I was happy with our architects but I acted as the energy consultant and kept a model in PHPP for each design to ensure they were in the envelope and where not they adjusted the design. So in the end we worked up three designs all of which were in the energy ball park before we chose the final design.

I am sure the U value will be the same but its not the I-joist bridges we are dealing with its the 220x310 gluelam and KERTO ends that butt up to the sheathing in a number of places it is designed to deal with. Today we have found evidence of a solution, used elsewhere, that involves drilling / punching holes in the foils. Given all this is helpful speculation I have engaged a WuFi professional to work it through.

Yes the walls, well parts of them - I joists and sheathing, are up on the sole plate and that is seriously nailed down.

Thanks for this Jeremy. Sadly we need the kingspan on the outside to deal with the cold bridges created by the large timbers in the structure extending to just inside the osb sheathing in several places. I have now sought out a firm to do a proper wufi analysis to check this out once and for all.

Consider it blown off! I liked working with our architects as they basically did a good job where we needed it and listened to what we told them. There are a couple of well known challenges they have: Firstly they don't do money, well / if at all. There are reasons for this, but essentially they see their role as giving the clients a vision of what the architects have gleaned from discussions with the client rather than an outcome that can be achieved within budget which is usually elastic anyway. Secondly the construction world is even fuller with new ideas than the academic world so expecting any one person or practice to have a grasp of all the ideas that are out there ... - I guess its why GPs refer you on to specialist consultants. Thirdly, perhaps most importantly, they are fallible, so the expectation, though not theirs, is that any issues will be picked up by the next part of the processes - the builder. Mike

Take a look through some old YouTube episodes of the Addams Family and you will get some great gate ideas and how to dress the rest of the place so it looks like the family that lives there is really 'out there'.

Yes - sorry Peter - I was only there last week and we talked about the possible array, should have remembered.

On another wrinkle - I have been looking at these in roof systems but I am struggling to get the panels flush with our fibre cement (Thrutone) tiles, this is similar to the problems I am having getting a water tight design for the roof windows flush with the tiles.

Where do you have yours, or are you running on micro inverters?

Hmmm... this is turning into something of a nightmare, we have all the insulation on site although we don't yet have the membranes - was on my list for this week. Anyhow the RIBA product selector sheet indicates this: "Joints between boards will facilitate the passage of water vapour under normal conditions of temperature and humidity." It is this that I had hoped would do the job for us and mean that water vapour could escape faster than the internal VCL. As I have not yet procured the VCL I could switch to 'AirGuard smart' which according to its blurb "lower sd-value of 0.05m (=25MNs/g) and an upper sd-value of 30m (=150MNs/g) for its adaptable AVCL DuPont™ Airguard® Smart." and should push it through in winter conditions. Alternatively I could run a lawn pricker over the sheets to puncture the foils!