Dreadnaught

Yes, nice solution. But I am aiming to avoid the extra complication of a hot return.

That makes sense. Looking online, the lowest temp for a TMV I found was 30º. Google in my hands could not find one that went lower.

True, although I was told that Geberit cisterns, which I am choosing, are insulated anyhow.

If the bathroom is a long way away from hot-water source, I recall a post where @PeterW suggested connecting the hot pipe also to the WC cistern so that flushing the toilet would pull through the dead-leg of cold water in the pipe. (I searched but could not find the old post.) Is this still considered a good idea? My bathroom will be about 15m from the hot-water source (a Sunamp).

@willbish, beginner question. In your (splendid) photos, all the walls seem to run at 90º to your joists above. What what if a wall ran in-line with the joists but there wasn't a joist directly above, just a void? In your photos, is it only the second photo that has staggered studs? Are those 300 centres? These seems to be some sort of spacer at the bottom or am I just seeing things? Really great to read about your experience. Thinking of using metal studs in my build.

Welcome to BuildHub, @DeanAlan. I am in central Cambridge too. A new-build Bungalow near the river. I'm at the foundations stage still a long journey ahead. Feel free to touch and good luck with your project!

I signed up for Ebico just before the British Gas transfer. Electricity only. On Ebico I was on the "Ebico Zero Green Fixed v5". Britsh Gas have offered me ""British Gas Zero Fixed Sep 2021", with no standing charge. Furthremore, the transfer looks to be possibly slightly advantageous. Possibly. The ebico tariff had a "Minimum annual charge of minimum bill value of £52 a year including VAT". The British Gas tariff does not mention the minimum, even in the small print. In September 2021, I would not be surprised if British Gas withdraw that tariff and I am then left paying a standing charge. During the transfer, they did mess up my meter reading, but that's a different subject.

Thanks @LA3222. Makes sense.

Do I need a radon barrier or will a normal DPM do for my raft? Tanners, in their raft design for me, a "Radon barrier / DPM" is shown as a layer between the heave protection and insulation and they state "Radon sump to be provided in accordance with architects drawings and specification." And the fellow who will be building my raft has said I need to supply the radon barrier if needed. But, checking the Public Health England webpage on Radon shows the area of my plot (Cambridge, UK) has a "Maximum radon potental" of less than 1%, which is the lowest in their scale. (I know the Tanners are in Ireland and, from reading other BuildHub posts on the subject that Radon is assumed over there.)

Thanks @Mr Punter. Yes, I sent the installer a photo of the exposed ground surface and he seemed happy. A concern about doing the MOT layer after the piles is whether it will be easy to spread it, presumably using a mini digger, and run the plate compactor around the 26x screw piles. Any relevant experience?

Question: lay the MOT layer before or after the piles? My build is finally getting going on-site. I have signed-up for building control and my ground workers will be excavating for the levels this week, with lots of muck-away (10x grab lorries for soils are mentioned). Next will be screw-pile installation. 26x screw piles and the installer is booked for two weeks time. The installer is adamant that service trenches (foul drains, electricty duct, and water main pipe, etc., all under the raft) should go in AFTER the piles. Then after that, my raft foundation requires 100mm of well compacted MOT Type 3 and 30-50mm of sand blinding. Do I lay the MOT layer before or after the piles? If before, it provides a good base for the pile installer, but the soil is already quite good and gravel-ly for the digger with its torque head. If before, the MOT will then be messed up by digging the trenches for the services. Anyone else have any relevant experience? What order did you follow?

At the risk of hijacking @NSS's thread, what dilution factor do you recommend? (My concrete raft is being poured in a month or so.)

I recall that @Jeremy Harris used PVA glue on his insulated concrete raft, presumably diluted.

I heard about a trick of sucking a plastic bag attached to a cord through a duct with a vacuum cleaner. Does that work in practice?

@willbish, my timber frame is not up yet, so not porgressed the stud walling at all yet, but still convinced of my decision to use metal framing. As you probably know, @nod is our resident expert.

You've prompted me to check with my window provider. Thanks!

… plus the lower standing heat losses for a passive house.

What type of tape to use please?

Thanks @Ferdinand. Very interesting. Yes, I read that thread before posting, thank you. It look like Toolstation are quite miserly with their discounts. And I will try some independent merchants of various sorts too, see what I can discover.

Thanks @Temp. Ah yes, this one: https://www.toolstation.com/content/tradecard. That looks like a MasterCard credit card. Not quite what I had in mind but might be an option.

Is it possible to get a discount from Toolstation? As a self builder building an entire house I will be buying a lot. Before I start spending too much, I'd like to lock-in some discounts if I can. Cash accounts only, don't need credit. I've signd-up for a Toolstaion account online but not yet picked up a "Customer Card" in store. Any tips about how to get discounts from builders merchants in general, but especially from Toolsation?

Thanks all! Very helpful. A busy day yesterday. The pipe is now (along with a fibre-option-cable duct) in and I have lots of photos that I can share with Anglian Water. In the end, we didn't remake the concrete road surface around the duct that I mentioned, with a road plate over for protection. This will enable us to easily revisit it again if Anglian Water requires it. Interestingly, a few days ago Anglian Water said that they don't come out to inspect the installation of a TBS. (temporary builders supply). I will send them the photos and see what they say.

My ground workers are moling my water pipe today in my access road. All going well. There is one duct for an electricity cable (see photo). They are proposing to go OVER the duct with the water pipe. The water pipe will be only 300mm deep at the point. Is that ok? Would it be at risk of freezing? Should I kick up a fuss and ask them to go UNDER the exposed duct SO its depth is 800mm as it is for the rest of the run?

Thanks @PeterW. That worked well. I bought 8x laminating pouches for £1 as an experiment and they come up a treat using an iron. Will be stapling them to the gate to my plot tomorrow. Three so far: 1) The house number (as my gate looks like a generic garden gate rather than a building site). 2) A sign saying "For site deliveries please call…" with my phone number. 3) And a generic site safety one like this…

Yes, my thoughts too. When I will prettify the cabinet, I intend to try to do it without calling out UKPN. I quizzed the guy from SSE about this when he visiting to fit the meter and he said it is a grey area, and suggested that it may be possible to swap the cabinet by simply moving the plywood backing sheet over with everything still attached and remain in compliance with the regulations. (By the way, I think it is UKPN's responsibility for moving a main fuse, not SSE as you mentioned, but I might be wrong.)