Mike

At that thickness even the most expensive insulant won't do much; in fact it would be more-or-less decorative as it would be bypassed by the outer skin sitting on top of the beam (and maybe by the patio door). You may be able to build the brickwork off Armatherm (ask them), but if the brick is already in place there's no good solution. Other than to dismantle it it and approach it differently (and claim the cost back from the structural engineer who designed it?)

I've done similar, though using a plastic angle to keep them straight.

This will give you a clue: https://www.researchgate.net/figure/sopleths-for-growth-of-various-fungus-species-and-the-lowest-isopleth-for-mould-LIM-0_fig1_272886603

+1 for blown EPS. The silver / grey ones provide somewhat better insulation than the plain white.

If under a warm / hot shower I doubt MVHR on boost would give you any discomfort in an open room. There's scope for some consumer testing here - just don't post the photos :)

Zehnder's recommendation is that it should be close to, but not directly over, the shower. No reason given, but my guess is that it's not about the functioning of the MVHR unit, but rather that the air being drawn past the person showering could, in some circumstances, feel uncomfortably cool. For example if you don't have a good shower screen & door in place.

You'll still want to keep a healthy indoor air quality, so you'll need it running to ensure that the air stays fresh. And if there is condensation within the unit, the fresh air running through it is more likely to help to keep it free from mould compared to stagnant moist air in the unit if you switch it off. So I'd keep it running.

I'd like to fit 230V Tridonic LED light engines, pictured below, (as suggested some time ago by @Carrerahill https://forum.buildhub.org.uk/topic/13775-led-llmf/#comment-227778) in some plaster-in downlighters. The instructions for the downlighters show two different mounting options for the electrical connection. 1) Shove the connection block / transformer at least 20mm away from the lamp, which would work: 2) Mount the connection block on a stirrup (supplied), which doesn't work when using a light engine... ...if you've not already spotted the problem, the stirrup is fixed to the part of the downlight that's plastered into the ceiling. But a light engine needs wiring to the connection block; do that and you can't change it if it fails, unless you rip the fitting out of the ceiling. So option 1 seems the logical thing to do. However must be some regulations that require the use of the stirrup in some circumstances - otherwise, why supply them - but If there are, I can't find them, and the supplier can't tell me either. I only recall stirrups being used with GU10 (& maybe Gu5.3) lamps, so my guess is that it's a requirement for them. But as one of those could be retrofitted to replace my planned light engine, maybe that still needs to be taken into account. But then why show 2 mounting methods? Going round in circles... If anyone is able to, err, illuminate me with what regs apply and when, that would be very helpful.

If inadequate insulation is indeed the problem, then it's either a specification or installation issue (unless the design required someone else to do something - for example to bury the ducts in the loft insulation).

If there's a long run of poorly insulated duct through a cold attic, then that would certainly be the expected result.

Thanks for the update - good to know that it ended well :)

Before you fit one, first consider whether you have good access from at least 3 sides to be able to clean around it properly, and to give it the space to set it off; a free-stander squashed between other items or against the wall won't look luxurious, it will look squashed.

I think that either of these approaches is good - and why I'm trying to cover both with my 2-tier UFCH controls. It's the stuff that falls in the middle where it gets difficult.

At least you caught it in time :) Maybe because he's recommending ones that only remove half the grease...

Yes, that's right. You also want the MVHR extract terminal a couple of metres or so away from the hood (so the hood does its job), plus a filter on the terminal as backup - either a sock filter (behind the terminal - a good idea on all extracts) or a purpose-designed kitchen terminal (with visible filter).

+1 for @Marko's advice. Also, make sure that the exhaust (to the external air) is either falling towards the MVHR unit, or towards the outside, so any condensation runs out of the duct. If you can find the space, I'd also upgrade your multifoil-lined housing with something thicker.

With grease filtering rated that poorly, I'd choose neither. BTW, recirculating hoods are normally chosen for MVHR, in case you've missed that.

I'd suggest 25mm minimum diameter flexible conduit, with a draw cord + gentle bends, but as straight as possible. Here in France that's commonly used for single cables Cat 6 / 6A cables - I hope so as it's what I've installed. Despite being against the standards, I've heard that it's possible to pull a pair of them through.

They will do better than fibreglass, but won't make a big difference unless you have space for multiples of 100mm. R (thermal resistivity) can tell you how much heat you retain / loose over a period of time, in a steady state. However it takes time for that product to heat up - that is, for the heat to travel from one face of the product to the other - before it stats getting lost at that rate R. The 'travel time' is the decrement delay (déphasage thermique in French) mentioned by others above. In general, the heavier and denser the material, the more the decrement delay will increase. If you're tight on space then adding solid timber boarding or an additional layer of plasterboard will likely make more difference (but still not that much) rather than adding any kind of insulation. Which is why churches, with their thick walls, are slow to react to temperature change. If you want to experiment, the Concrete Centre has a free calculator that you download, from https://www.concretecentre.com/Publications-Software/Publications/Dynamic-Thermal-Properties-Calculator.aspx, if you subscribe to their newsletter.

No, none at all. I used it professionally (as a manager) many times, always specified it when I had the choice, and have always used it on my personal projects, without problems. And although the pipes are a bit more expensive than plastic, you save money on stone fill & spoil removal (you can often backfill with as-dug material). And if you're unlucky and your trenches fill with rain, it definitely won't float, as plastic can. I've only laid the 100mm personally and it's pretty easy. No problem to DIY single-handed if you're practically inclined, hire the recommended pipe cutter & follow the manufacturer's info.

Please do - looks just the sort of thing that I'm aiming for! I enjoy dabbling with the technology, but it's always interesting to see what others have done for inspiration, tips & ideas. one of the reasons for going with the Shelly as the base-level programmer is that it supports MQTT. So far I've installed 10 SHT31-F temperature & humidity sensors above my peculiar unventilated ceiling insulation and will be adding some similar room sensors, plus a bunch of DS18B20s for the UFCH. I'd also like to tap into the Nepronic SHC80 RH sensor that came with my adiabatic cooler, if I can work out how to connect via Modbus / Bacnet.

There's an interesting graduation. If you can get a fine / loose points on your license, then it's complied with - these days French drivers even stop at pedestrian crossings & stop signs! On the other hands, it seems that if you're a farmer then you can get away with most things... ...especially those :)

Almost - 1997-ish - though I'm sure you'll have done more than me! I agree that it can easily be overdone. Having said that, my latest UFCH, currently with very manual on-off controls (plugging / unplugging an extension lead) will be getting 2 layers of controls once the renovation is completed. Basic, using a Shelly Pro 4PM as a simple weekly timer, plus optional 'advanced' controls using a Raspberry Pi which may even do some weather compensation :)

One of my friends just built one where they had to barrow / carry everything through several gardens, thanks to the cooperation of her neighbours. Otherwise it would have had to have gone a longer way around via a footpath and through her house. And my current renovation is on the 6th floor with no lift and no parking. So yes, there are almost always options.

Hepworth SuperSleve (clay) below ground. No strong preference above ground.