Mike

While I do use downlighters, but am not keen on using them in rows for general illumination - though I know many do. Though for a regular grid of downlighters, I do commend your restraint on the quantity selected which, subject to beam angle, could create some variation in light and shade. But it's not the way I'd do it. Personally I'd first be thinking of choosing lighting to suit the particular uses of the space - so lighting above the dining table and the kitchen island, to the sides of the sofas for reading / watching TV, and additional task lighting over the kitchen worktops. That could be a mixture of pendants, floor / table lamps and spots, for example. Then I'd be looking at highlighting any particular architectural features (including plinth lighting), or where any paintings or other features may go. Finally I'd be considering whether or not there are any particular gaps that may need additional illumination. Ideally, have at least 3 different layers of illumination, with dimmers on at least the principle layer. Other factors to consider are beam angles, light temperature and the colour rending index of the bulbs.

A question for the non-smokers. My upcoming MVHR install, in an apartment, has only two possible places where the outside air intake can go: Within 1m of an external landing, where people sometimes smoke - and the smoke will sometimes get draw into the inlet. This option would have a short intake pipe, but a significantly longer exhaust (x 4). Within 1.5m of the top of a neighbouring SVP - and the smell from that will also sometimes be drawn into the inlet (not so often, but for longer). This would reverse the pipes - a short intake and a much longer exhaust. Due to space restrictions, the exhaust can only go in the other location to the intake, so I have to decide between a choice of smell-source vs exhaust pipe length. The pipes will be well insulated, but can only run through the ceiling space. In theory either smell should be eliminated by the carbon filter that I'll be installing, and if so I have a preference. But has anyone got experience of how well either smell gets filtered in practice?

You wouldn't generally fit a vapour barrier ever. However there's a difference between a vapour barrier (stops moisture vapour movement), a vapour control layer (allows moisture vapour to move through it in a controlled way - a.k.a. a 'breathable' membrane), and an air barrier (stops air moving through it). Thinking has changed over recent decades and now, in most circumstances, the advice is generally to include an air barrier - to stop the movement of air - but not to stop the transfer of moisture vapour (to allow any moisture within the structure an escape route). In some circumstances that may involve fitting a vapour control membrane. In this case I'd just cut the PIR board a little loose and foam it in place using a flexible breathable (moisture-permiable) foam such as Ilbruck FM330. Or choose an alternative insulation. And a vapour-perimable emulsion paint; if you use a standard vinyl one then the wall is only going to breath towards the outside.

Perhaps by using a car with swappable batteries. Or, in an urban area like Bristol, by joining a car share scheme, rather than owning a car.

That's already happening in France. For over a year it's been illegal to start to rent most properties rated below below E, and illegal to increase the rents of those already let. As a result, the value of poorly insulated property is falling, and more properties are being sold because the current owner doesn't want to upgrade. Between September 2019 & October 2020, the number of properties rated E, F or G going to market went up by 10% to 74% depending on the region. And G rated properties sold for between 5% and 15% less, depending on the region. Unlike the UK, various loans and tax-breaks are on offer to help landlords upgrade (though not for DIY upgrades), and there are now buy-upgrade-rent investors taking advantage of the lower prices and the financial incentives.

It's been a well-known problem for decades. Only use them if you have to.

Not sure how affordable or available it is, but there is at least one company that produces an insulating plaster/render that incorporates polystyrene granules - Vimark Thermointonaco. It could be useful if/when you need to re-render the outside. In Europe I've come across one or two similar products incorporating aerogel, but not in the UK.

I've done the same in the past & agree - it is a good solution. And, at least with some water companies, a larger ongoing standing charge.

That would be my choice too.

If you're no more than 2 floors high, a 75mm vent is fine under English building regs.

Certainly rare this year, from what I hear. Here in France the summer daytime RH can be similar to the UK, but at night it often drops below 50%, so it's an easy decision.

For a Pro version of the same - albeit with a significantly higher price tag & the need for a dedicated water supply & drain - there is the HomEvap Cooler. From memory it can cool by about 2,800 W 1,950W, maximum. I plan to install one ready for next summer.

I've got a cordless 125mm Dewalt 1000W machine, which lasts a good time on a 5Ah battery. Would buy it again if it packed up.

25mm is good and, at least in some areas, note that your standing charge will be higher if you select a larger diameter.

Four choices - take it down to ceiling level, fill with expanded glass or polystyrene beads (but not with vermiculate, which is hygroscopic), and make it airtight. - leave it just below roof level, fill to ceiling level as above, seal it airtight at ceiling level and in the room, add an airbrick above ceiling level to ventilate the remaining part in the roof space - if it's on an external wall and you anticipate it getting damp from rain, etc., fill as above but don't seal it - demolish it entirely, as Conor suggests. My strong preference.

Alan poses some good questions. I suspect that to properly fix it could mean stripping the entire roof to remove the load and straighten out the rafters (I guess that they're out of alignment too?) before replacing or reinforcing the purlin. But I agree that a SE report would be very helpful.

It's possible in principle, if the services in the highway are out of the way, but isn't compatible with all soil conditions. It's not going to like stony ground, for example. Even if you think you know the soil, you may come across a heap of covered-over builder's rubble / old foundations / other obstruction, so have a back-up plan.

Either that, or use a high-strength plasterboard - I'm currently using GypsoLignum. If you have only plasterboard, then I've found Fischer DuoTec nylon toggles to be good.

I've been installing exactly that in France today, using Knauf's Easy Click (various ways of fixing it, here's one). There are multiple companies that produce the plastic stand-offs in Europe, including Siniat, but I've not seen them in the UK.

Worth mentioning that they can include methane, which is explosive.

I remember trying to convince people that double glazing was worthwhile.

If you are laying tiles of traditional size and thickness, then you could. There are some on the floor above mine laid just like that - very wonky (it's a timber deck) but not overrun with cracks after nearly 200 years. Preferably you'd lay them over a sand bed laid on gravel or shingle - the traditional 'decoupling membrane' that's been used for centuries. Modern rigid construction methods & thin large format tiles would be two key factors. Modern decoupling membranes are the response.

1.28 is referring to the vertical stack, not the connection to the WC. The part between the WC and the stack is the 'branch connection'. So the rule at 1.15 applies and for an 80mm outlet toilet you either need a minimum 80mm or 75mm pipe. But, as Temp says, in practice you're limited by what's on the market. And I too would stick to 110mm - unblocking drains isn't my idea of fun.

Free of charge in Shelly's cloud, if you're not recording it locally, from where you can also download it as a CSV file.

They should. They still fail. We had it in the previous house. Was a pia to change it. A lifetime of '100,000 hours' is most likely referring to the 'catastrophic failure rate', often 10%, under which no more than 10% of the bulbs should fail within that 100,000 hours. But someone has to buy the ones that make up that 10%. Good advice to buy quality LEDs from a reputable company though.