Dreadnaught

For example, in @ProDave's case of a 2kW heating-requirement to maintain a temperature difference of 20º, he would need to impart 48kWh in a 24-hour period. But could he use four Willises for 4-hours at cheap rates and be done for the day, costing him £2.40? (A gross simplification I know.)

How fast I wonder can the concrete raft heat up, in its role as a thermal store? One thought about having a single Willis, double or even triple Willises, is that these new electricity tariffs restrict the lowest cost to 4-hours, 7-hours or 10-hours each day (and the 4-hour one is particularly attractive at 5p per kWh), it might be advantageous to heat up the raft quickly. Three Willises could impart the raft with 9kW, if it could only take it.

I have a supply-only quote from AFT as well (plus a full-installation quote). I am following this with discussion with interest. If I thought I was up to a DIY-install, I would be tempted.

If you're in the Apple ecosystem, then "HomeKit Secure Video" ensures high levels of security and only local processing of the video. That's what I will be going for. It is quite new so cameras with it are only just now becoming available. Netatmo and Eve have both announced them recently. (The software at launch is lacking some features and has some reported bugs, but it will be improved fast so it does not cause me concern.)

Have you considered adding secondary glazing separately and in addition? It can be very effective at reducing noise.

G4 is the standard dust filter. F7 is the upgrade option and a much finer filter, and so captures more fine particles such as pollen. An MVHR has two built-in filters to prevent the heat exchanger becoming clogged with dust. One prior to the heat exchanger on the fresh-air intake side. And one prior to the heat exchanger on the stale-air extract side. Personally, for my forthcoming build, my intention is use an F7 on the intake side and and G4 on the extract side. But to protect the F7 (which are quite pricey to buy) I also intend to mount a filter box outside the MVHR within the intake ducting run from the outside. In this filter box I will place a second filter, a G3 or maybe G4 pre-filter to catch some of the particles before the clog-up the F7. (G3 might be best as it will resist the airflow less than will a G4).

I looked at your drawings with a particular eye on the roof make-up. This is because I am presently specifying the flat roof for my forthcoming build so it is foremost in my thoughts.. I don't know if you are aware but yours is an example of a what's called a "hybrid" roof, a hybrid of a cold roof and warm roof. You have some insulation in among the structural elements and some insulation above the structural elements. I don't wish to alarm you but you might be interested to note that Bauder say "This type of roof construction should not be used unless a full condensation risk has been undertaken". The reason for this is the lower layer of insulation can cool the void increasing the risk of condensation within it. And it is of course moisture, more than almost anything else, that destroys buildings. Here's a link: https://www.bauder.co.uk/technical-centre/technical-literature/design-guides/flat-roof-design-considerations/thermal-design-insulation-and-consideration Did your architect do a dew-point (condensation risk) analysis of your roof, I wonder? Or perhaps its a standard details and so they are relying upon someone else having already done it?

Yes, if its available gas-over-ASHP was the consensus view that I picked-up from a couple of years of solidly reading this site. There is a gas main is in the access road immediately in front of my plot. And so gas it is for my new planned modern bungalow, which is sufficiently small that I can use just a combi-boiler. From a purely intellectual perspective, I would love to skip gas altogether and go electricity-only. But the economic perspective does not support this (yet). The initial capital cost for an ASHP is much higher than a combi-boiler and the payoff of an ASHP is not sufficient. Furthermore, at least for now, any buyer of my dwelling is more likely to have more confidence in a gas boiler than an ASHP.

Not sure if this is what you had in mind (without prices): Look from Page 10 onwards. https://www.jhplumb.com/system/brand_attachments/1033/original/Hep20_Technical_handbook.pdf

It will only be cold and hot water, no heating pipes, and only to supply one en-suite. I guess I will need a handful of Pro Clima seal grommets for pipe feed-throughs. (I am also wondering whether to run a gas pipe through the joists too, but that's another story).

Good point. Airtightness lawyer at ceiling level (Pro Clima Intello Plus under WarmCel, just like MBC usually do). Was intending to seal the pipes as the passed through the membrane. Warmcel is pretty airtight too on its own. But you raise a good challenge to my thoughts.

Thanks @Nickfromwales. Sadly the gods of planning have decreed a fully-flat roof (with greenery on top). No choice. I will however have lots of 300mm open-web joists just begging for pipe runs.

I'm following this discussion with interest as I am planning a bungalow too and had intended to run much of my plumbing through the open-web joists in the ceiling/roof, like @Oz07. (In my case I have a flat roof.) In my case, I am not intending to have any radiators, just UFH. Would this mean I aim unlikely to have a problem I wonder?

Oh, what I saw in the videos I watched was that glue-down LVT was inserted under architraves, at least in a retro-fit situation. The architraves were cut with a multi-tool so it would fit underneath. I believe that LVT requires a few mm of gap around its edge. Not sure why. But it would indeed be good if this was concealed by skirting.

Watching some more online videos on LVT: DIY install of click/floating LVT looks very very easy. But DIY installing glue-down LVT does not look particularly difficult: slightly more complicated but not difficult. Given the cost advantage of glue-down LVT and that it is thinner (for UFH), I think that glue-down LVT will be my choice for a DIY install.

Interesting topic for me, as I am researching LVT as well for my build. @vivienz has the glue-down type too. Why is that I wonder? Click/floating type sounds easier to install DIY.

Could it have one of the new eSIMs, soldered on to a circuit board somewhere? https://en.wikipedia.org/wiki/ESIM

Thanks all. I've been looking online at how to seal a sealed-unit into a wooden aperture… and so have descended into the world of window putty and butyl glazing-tape and a myriad of other tapes, caulks and sealants. I assume the concerns are twofold: (i) rain- and wind-proofing the exterior (including the fate of the rainwater that runs down the window); and (ii) airtightness on the interior. Airtightness I imagine is just a matter of the right tapes as with any window. The tapes then being hidden by the plasterboard in the reveal. Any thoughts on rain- and wind-proofing on the outside anyone?

Thanks. Unsure what this means ↑ .

For a fixed window (external, non-opening), is there any reason in principle why one could not skip having a window frame altogether and mount a triple-glazed "sealed unit" directly in to the aperture created in an exterior timber wall, perhaps with only a minimal bracket for fixing purposes? It strikes me that frames are expensive, complicated, (sometimes greatly) reduce glazing area, and are designed mostly to enable windows to open. And frames also have comparatively poor U-values (even for Passivhaus windows) than the glass they contain. Problems I can imagine: Sealing and ensuring water runs off properly. Coping with differential heat expansion (bang goes the window on a hot day!). Access to swap the sealed unit if necessary. Undoubtedly, there must be something fundamental that I am missing. Please enlighten me.

Ah @AnonymousBosch, so I take it that its a Gaulhofer window (which confounded @craig)? Off topic I know, but could ask about the frame/glass ratio there? Are those standard frame widths or are they a special request by you? The reason I ask is because I will have four windows which are currently planned to be within 685mm apertures. But if the glass pane would end up being as narrow as the one in your photo I will be tempted to widen the aperture.

Could the same be advised for rooflights I wonder? And maybe even windows too while we're at it?

@vivienz, spotted on Amazon … https://www.amazon.co.uk/Palram-NANCY-1500-GREY-CANOPY/dp/B07KZVV54F/ref=asc_df_B07KZSMJP2/

@vivienz, regarding water creeping-in under your front door, does your front door have a bottom drip detail (a.k.a. a weatherboard, rain deflector, or rain deflector)? Could you post a photo of the bottom section of your front door? I recall that @mvincentd had an issue with such a detail. This door has one as an example:

@Ktelobb, yes, exactly the same with my plot. And with mine, the council had adopted a new Local Plan in the intervening period which meant my new plans had some hurdles to jump (I ended up with a green roof as a result). It implied that the old approved design would not have been approved under the new Local Plan.