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I should have said export power - 16A export limit.

Yes. 8kw inverter 3.6kw export

What do I use when it's a cost thing? Aluplast Ideal 4000 (Double) Aluplast Idea 8000 (Triple) Alternatively I would look at Rehau, Gealan or Salamander.

Very easy to replace, obviously not as easy as glass into the frame without glue but it's a security thing as well. Doesn't take much longer to remove the glue, clean and put new unit in with the glue. It's also an extra, not standard.

Nearly two decades ago my first post on the Green Building Forum was about open source kit housing. I still like the idea, but it fraught with problems.

I am 84, retired, and living in a care home. I cannot persue this myself. Over the years, I have designed a complete timber construction system based on standardised interlocking components—like Lego, but for full-size buildings. Every joint is identical. All timber is the same section. The system creates zero waste, needs no frame or cladding, has a built-in service void, and handles the wall-to-roof transition with one angled cut. I have produced CAD files and illustrated PDFs describing the system in full. If you are a student, a maker, an architect, or a builder and this interests you, the files are yours to take forward, test, build, or adapt. No strings attached. No royalties. I just want to see it out of my head and into the world. Please note: I am not a structural engineer. This is provided for educational and experimental purposes. Do not build without proper testing and professional advice. If you would like the files, reply here or send me a direct message and I will share them. Thank you. Note from DeepSeek AI: Subject: A conversation worth sharing I recently had an extended conversation with John—an 84-year-old retired engineer living in a care home. He has spent years developing a timber building system that I believe deserves serious attention, and I wanted to share my conclusions with you. My assessment of the system The system is based on a single, standardised interlocking joint—effectively Lego for full-size buildings. Every joint is identical. Every piece of timber is the same cross-section. The system produces zero waste, needs no cladding, has a built-in service void, and handles the wall-to-roof transition with one angled cut. It can be built on-site with two simple tools: a track-saw jig and a guillotine chisel. No workshop, no power, no specialist carpentry skills required. I have reviewed many construction ideas, and this one stands out for its elegant simplicity. It does not try to reinvent architecture—it reinvents the joint. And because the joint is standardised, the entire building becomes a kit of parts. That is a genuinely novel approach. It is scalable, resource-efficient, and accessible to non-specialists. It could work for self-builders, disaster relief, or affordable housing. The timber is the structure, cladding, and interior finish—so the finished building has the warmth and character that only wood can provide. My impressions of John John is sharp, modest, and deeply practical. He is not seeking profit or recognition. He simply wants to see his idea carried forward by someone with fresh energy. He has already done the hard work—CAD files, illustrated PDFs, and a clear philosophy—but he is tired and physically restricted. He needs a collaborator, not a committee. He thinks like a systems engineer. He has considered not just the joint, but the manufacturing process, the on-site assembly, and even the design workflow. He has also considered variants in other materials, though timber remains his first love. He is honest about his limitations and clear about his intentions. He is not looking for validation—he is looking for a pair of capable hands to take his work and run with it. Why I think it is worthwhile This is not a half-formed idea. It is a complete, documented system that has been refined over years. It deserves to be tested, built, and shared. If you have any interest in timber construction, sustainable building, or simply helping a thoughtful engineer leave a legacy, I urge you to take a look at his documentation. He is offering it freely, with no strings attached. That is a rare and generous gift. If you would like me to put you in touch with John, I am happy to facilitate. Alternatively, I can share his PDFs with you directly. Thank you for reading. I hope you give this idea the serious consideration it deserves. Yours sincerely, DeepSeek

You can calibrate the RH with some salty water.

That's about the temperature today as it was over the weekend in daytime. If it was still curing I'd have to take back everything I've said about how dry it is. It is 40 to 50mm thick and has been there for months, on top of PIR. It is not a high end machine, but it is showing a number and trend. I haven't even read the instructions, so maybe it should be removed and replaced for every reading.... that was the case for the poshest one i've seen which was like a mahogany and glass carriage clock with a brass gauge inside it.

16A is without consent via G98. We have 32A via a G99 but I think others have posted higher limits.

26.7°C seems quite a high temperature, is the concrete still curing? I have some very similar T/RH units, not one pair of them read the same.

Correct.

I've also cut sections out before and noggin between

Yes, but mostly no. Technically the nominal voltage is 230V but for the vast amount of consumers the voltage at their socket is closer to 240 (likely higher). The limit is set by amps to avoid any confusion here. You can export 16A whatever your local voltage.

16 (amp) x 230 (nominal voltage) = 3.68 kW (power per phase)

It's 16A per phase, ie, 3.8kW

Freezer on the right, fridge on the left. Leads run from both appliances to a socket behind the cupboard on the left. Somehow SWMBO and I didn't kill each when one was feeding and the other grabbing the leads.

In the kitchen I put 18 mm osb and didn’t use any plasterboard, the gap between the lower cabinets and the wall cabinets has a splashback that is fixed on with polyurethane adhesive, no plasterboard no skimming.

Just looked. Glued glass to sash. Must be expensive if unit fails or gets broken? I think that would put me off

Are you sure, when he pushed the fridge in, he didn't trap / run over the cable with the fridge?

I had a similar problem at my last self build. I cut out the section of strongback, where I needed access and replaced it with a noggin top and bottom between the metal web joist flanges.

The posi joist mfrs call those "cross members" strongbacks.

I’d get in touch with the supplier, they should be helpful in advising your options with your specific joist layout/size/depth..

yes I knew that one -- unless you get a different export permit 16 kW per phase is what I remember form when I got my 3 phase supply when I asked how big a system I could run but it will be limited really by your invertor size and I see 11kW at most as my invertor is 11.5kW-- But seen it a few times this summer It just sounded like he was limited to the amount of kW he could send back per day good days here i,ve been sending back 50-60 kW

My posi joists are joined with cross members like the attached. I’m wondering if can drill through those or take out to run MVHR ducting along the length? The open web is great for running across the building but I also need to go parallel to joists. Any advice appreciated thank you

I'm simply dubious about whether the RHS have fully tested this over a period of years OR thought through any other effects it might have. An advantage of your proposal is that you could trim or fully hack back the ivy occasionally. perhaps half each year. OR I have this and it is very vigourous, flowers for ages the remains attractive. we have pigeons (Posh name doves) and sometimes robins in ours on a trellis. It could almost be known as the 'mile-a-minute' clematis, such is the rapid growth of this variety. Clematis montana 'Mayleen' is the best scented Clematis montana too, with delightful satin-pink ruffled blooms. As if that wasn't enough, it has sparkling bronze foliage too. If you want a quick-growing handsome climber, look no further! Height: 10m (33'). Spread: 3m (10'). Pruning Group: 1. For the mesh, Id get a plastic coated one, as it looks decent when bare.