Iceverge

I would sit them on a precast sill on the outer leaf. Preferably one with no more than a 25mm upstand for thermal bridging. Plenty of flexible sealant for the brickwork to window connection. Strap and tape the window to the inner leaf for security and efficiency purposes

Thus far the count is exactly precisely zero since inredid my new build with Hep2O. 4 years is a drop in the ocean though. I'm still living with both excellent and average decisions from 1950-1960 on the farm from my grandfather. I reckon you could plumb a house for 100 years+ if you were clever. Imagine the satisfaction from the afterlife when your great great grandsprog says under his/her/it's/their breath: "Wasn't great old grand Nick a clever C*nt." Floor drains with U bends that take a basin or shower in the side are more robust than airless traps in my opinion. Merry spannering.

Can you run the MVHR on supply only. As a kind of PIV with the windows on the latch it'll push lots of dampness outside that way.

You're dead right. Loads of manufacturers selectively use data to make their wares appear better. That said this number kept coming up. Egger, Partel, Sign etc all have the same number. My best guess is it's a DIN standard but it's behind a paywall. I didn't tape the staples in our ceiling membranes unless I could see a rip/tear. We blew a 0.31Ach50 so I'm not sure it's 100% needed.

As you're DIYing for DHW I would recommend using Hep2O push fit. I thought it was excellent. A radial layout from the tank. 10mm pipe for everything except the showers, bath and kitchen/utility taps. Keep the UVC as close as possible to the kitchen tap. I preheated the hot manifold by convection by positioning it directly above the UVC. I'd have liked to have included a floor drain in every room with a pipe joint or a tap just in case of a leak. Next house.......

Sounds like a top spec build. Good luck with it. I think someone here built an MBC twinwall over a basement. The name escapes me. It may be an option for you.

That number I used was from Siga's website. I don't think BS defines it unless you have more insight than me? To @Rick734s question. Something like this would be fine. https://insulation4less.co.uk/products/vc2-air-leakage-vapour-control-layer-1-5m-x-50m-75m2-roll To connect the membrane to the brick I would use an airtightsealant. Orcan F is the one that popped up first. https://www.earthwiseconstruction.co.uk/product/airtightness/adhesives-primers/orcon-f-airtight-sealant-adhesive/?attribute_pa_orcon-f-size=310ml-cartridge&gad_source=1&gad_campaignid=21761028231&gbraid=0AAAAADqL4zA7HZs48ZWRJyFGMUuzu-U3k&gclid=CjwKCAiAu67KBhAkEiwAY0jAlZBJ-cvv1xqU3kk-2xm2BrsDsiiC-IiArhamJDFKawbitr-HRg56cRoCRbgQAvD_BwE I would always be in favor of a service cavity to avoid puncturing the airtight layer. If you have enough space 50*50mm battens work nicely for 50mm mineral wool to insulate and boost the U value a bit. Maybe Santa will bring some, I think I can hear him rattling around up on the roof.🎅

Reflections from the windows ruin many a good TV room. TV needs to be on the same wall as the windows, not opposite. I reckon the top of the TV should be no higher than your head when sitting. TVs above the fireplace are for massicists. The Fireplace will get a bag of logs at Christmas probably and the rest of the time you'll heat the house ussing common sence so I wouldn't compromise the audio visual experience for the sake of moving the sofa once a year. Sofa at 1. TV at 2. Two nice light arm chairs at 3 and 4 that can be turned to watch the TV or spin them around to sit facing the fire

TLDR: 1. DRYING MUST EXCEED WETTING 2. Forget about the microscopic holes (diffusion)!!.Worry about the big ones (airtightness) !! 3. Some moisture will always get in, just ensure it can get out again. Low Sd materials are king here. Merry Christmas!

Try playing with the numbers, there's always truth there. I'm sure @SteamyTea will concur. All the formulas are online or there's also chatgpt. Take your 11mm OSB. It has an Sd value of 2.5m which is quite vapour open. A house with an internal RH of 60% at 20deg will exert a vapour pressure towards the outside on a winter's day. Assume it's 5deg and 90% outside. Over an hour about 0.18g will diffuse through 1m² into your wall. Now put a 1cm x 1cm hole in the OSB and exert a 50Pa pressure difference on the wall representing a strong breeze blowing on the wall of the house. Over an hour an extra 7g of moisture will end up in the wall. In short a 1cm² hole will loose as much moisture into the structure as 40m² of very vapour open wall on a typical February day.

Got it in one. In layman's terms all that matters is that "drying exceeds wetting". Vapour barriers will in theory have less diffused moisture making its way into a structure than Vapour control layers. However they have such terrible drying qualities that in practice the trade off is they result in wetter walls than VCLs. In any case moisture diffusion is the hill that too many people die on unnecessarily. Holes in imperfect airtight layers are massively more significant. Often carrying hundreds if not thousands of times more moisture into a structure.

Sd value above 100m is a barrier. Barrier will be worse. It won't allow construction moisture to dry back to the inside. In practice there will be holes and imperfect sealing of any membrane. Any moisture ingress will dry over time through a lower Sd material and won't through a Vapour Barrier.

It's gaping air leaks to worry about not diffusion. OSB will be adequate for your purposes if you tape it diligently, however a vcl may be faster. Beware the difference between a vapour barrier and a vapour control layer. With a barrier you'll always run a higher risk of Interstatial condensation.

Marvellous. The most important thing when renovating an old bungalow is to immediately bulldoze it.

My day job isn't climbing scaffold or screeding concrete so barring any disastrous health problems I expect I could do it until at least then.

At brief glance I reckon they're inline with most other European economies? Exemptions being the Nordics with good hydro and nuclear and Hungary and Turkey with government price controls? On the other hand I think private enterprise short termism is a bad fit for vital public services like transport, energy, water etc . The likes of EDF and Thames Water should be trading only in decades long bonds to force them to take a long view rather than normal shares and dividends.

It's an issue. In the UK 60 years ago there was 4 workers for every pensioner. It's closer to 3 now. In the 1960s pensioners were 6% of the voters, now they're closer to 18%. Policy is following the votes. Underspending on new housing, infrastructure, energy and education in favour of protecting homeowner tax breaks, pension protection and old age healthcare. These policies aren't economical productive so the county is suffering. Retirement should be raised to 75 years old to match the 1960's ratios or this problem will deepen.

Grants typically just shove up prices. A progressive carbon tax would have been better money than any grants in my opinion. And government to get out of the way. For example a blanket planning (and listed building ) exemption to any house changes reducing its energy use. Triple Glazing, EWI, ASHP, solar etc etc.

72.5mm insulated plasterboard chamfered top and bottom and screwed through the existing plasterboard into the rafters. Foam either a good low expansion foam, tape and skim the joints to wall and ceiling. Don't bother taking down the existing plasterboard. No space gain in the room and will create an enormous mess.

The roof will be able to dry inwards. I would just tape the OSB for airtightness and leave it at that. You could sandwich a VCL between the OSB and PIR but it's unnecessary in my view.

For not an awful lot more cash you could have an insulated metal panel shed. Or if you want plug and play... Should be saleable in years to come or it'd be easy enough to tart up if you didn't want to be continuously reminded of choc ices!

Strange. Do you have a trunk and branch system or a radial?

Just tape the OSB for airtightness and forget the YBS. Insulate the service cavity with mineral wool. Ideally run the battens at 90deg to the rafters.

There's no magic with dMev Vs PIV. Both are just a method of moving a continuous stream of air through the house. I used to leave the hob extractor on when I went out in an old damp rental cottage we had to dry the place out. It's just a fan moving air after all. In both cases you'll still get condensation if you have trapped pockets of air like behind curtains etc. @TakeshiKovacs as an experiment try leaving a bedroom door open to the hallway, curtains open and the bathroom/kitchen extractor fan on constantly for a night. If you can manage the light and noise. It'll solve the condensation I bet. You could also crack the window open a few mm and leave an air gap to allow some air flow through the bedroom to the extractor. Keep us posted.

Masking tape along the perimeter would avoid the need to scrape it from the floor too.