Sparrowhawk

What happens if you set the heating system at 35 and run it for longer? If your Baxi can modulate down enough I understand that's the more efficient way to run it.

I got my foam gun out today. It's been almost a year since I used it and it has a nearly full can of Illbruck FM330 attached. The gun still works great, it hasn't clogged up. The foam however spattered down one side of a window and then gave up coming out. I've shaken it for minutes and nothing. If I pull the trigger a tiny bit of foam oozes out and that's it. I've stored it with the can upright so thinking it's not the gun and that the propellant has leaked out? Anyone had that happen before?

Yes I think I could. Currently there's 100mm gap and 50mm PIR between the rafters, so if I used a 60x200mm rectangular duct, had a 40mm layer of PIR and packed either side of the duct with insulation that would do the job. I'm not going to be able to insulate it properly where it passes over the wall, but that's a short max 0.5m length that will be cold.

Hi @retro and welcome to the forum. Do you have a floorplan for your flat you can share? Is it open plan, square, rectangular? Would you hang the ducting from the ceiling as "industrial chic"? We have the same pain. Where have you identified cold bridging on yours?

His YouTube/Instagram/Tiktok are good fun.

My thought too. If you can hear it as you move, how much flex are you feeling in the floor? Between the plywood and laminate won't there be a layer of particle board or similar, which would be a place that could be wet and make an audible sound?

It's on Amazon at https://www.amazon.co.uk/Ultimate-Energizer-Guide-Effective-Electricity/dp/1652228403. The most illuminating review I read said: Edit: plenty of videos on YT reviewing/exposing it.

While I've got the floors up I want to install MVHR ducting. There are ground floor rooms where there's no vertical drop from the loft, and the joists run across the direction the ducts need to go. So I started looking at how I could cut big holes in joists. FWIW the first floor joists are 7 inches deep.

Welcome @marshian, that's an impressive reduction in gas usage you've managed! I'd like to know more about this as when I modelled insulating our suspended wood floors it reduced the heating demand by less than 10% - nearer 5% IIRC. Do you think the reduction in heat loss you saw was from the insulation or from improving airtightness and reducing losses due to draughts through the floor?

Welcome to the forum @Novice Becky! There's a few of us doing retrofits here on varying budgets. Thermal cameras are great but I found a home-made blower door more useful for finding where my airtightness was poor (or in this house, finding the few areas where it was good 😀). I made mine from an old door and a mains-powered Screwfix fan. Your gas usage makes ours look good, but I suspect you are sensible and keep your house at 18C+ throughout the winter. Have you done heat loss modelling room by room to work out where your biggest losses/biggest wins are? I did mine in a spreadsheet but for £12 https://www.heat-engineer.com/ looks like it would save a lot of time. Tweaking the U-Values afterwards showed that floor insulation (which I'd been prioritising) was going to do v little, while CWI and airtightness would make a massive difference to heat loss. Finding windows fitters that know more than screwing the window into the wall and squirting a bit of foam around - 'nuff said. I want to install my own windows next time. Flagging this as you'll need an air gap between the cladding and insulation to make sure it doesn't rot (something I'm dealing with here at the moment, only MDF wall with UPVC cladding directly attached). Have you checked the makeup of that section of wall? Thanks for sharing your experience of the retrofit assessment you had, I'd been thinking about whether one was worth it to stop me procratinating give a "this is how to get there" guide, but came to the conclusion they were unlikely to have all the answers either - or worse, would have less knowledge than I've gleaned from this forum.

In the states they've got products on the market to let you make holes bigger than 65mm / 0.25x the depth in solid joists like this Joist Repair Hole Reinforcer 2810HR By Metwood or this one from Skyline. Over here in the UK I've seen one for I-Joists so you can make large holes in them, like the I-Joist Hole Support from Simpson Strong-tie but nothing for solid joists. Are there any products approved for use here?

I've seen glue mentioned on this forum a few times, and my thought is "what happens when you need to lift them?". T&G is bad enough, but if glued as well is this not a install-only process which will cause problems for future maintenance?

When the Pi 4 prices increased I got a second hand one of these https://www.lenovo.com/gb/en/p/desktops/thinkcentre/m-series-tiny/m900-tiny/11tc1mtm900 off the bay for less than the price of a Pi. It's been superb and unless I needed a Pi for an IoT device I don't see any reason to go back.

When using 25-50mm of acoustic insulation in a 100mm+ wide wall, how do you place it for best results? Staple it midway with air either side? Pushed up against one of the plasterboards?

Penetrations. I've set a new record this week. Not counting joist ends (I can poke a twig into the cavity round most of them) there's 7 penetrations into the cavity in 1.2m. And 5 penetrations through the ceiling to the room below, which houses the boiler and fusebox. Rewring TBD later. Plan is to fill the gaps or coat the entire damn section of brickwork with something - mortar? plaster? - and then use Blowerproof to seal round the joists. I'm not taping this lot. Happy weekend everyone!

Blowerproof sell a Non Shrink Gap Filling Mortar to use on bigger cracks before painting with Blowerproof liquid sealant. What can I get from a local builders merchant that will do the same job?

Seconding this. When thinking about remodelling we got big sheets of cardboard, put them up where the walls would be and painted them. We've kept one up to see how much of a pain the doorway position is. I envy people who can see 2D plans or 3D renders and visualise themselves in it. I need to inhabit the space.

@Gus Potter are you sure you mean @jayc89 and not @Nick Thomas?

I've got a patch panel on the marketplace if you want one

@NCXo82ike Did you install ducting in the chimney stack in the end? I've been thinking about this for our house so your experiences would be good to hear.

They are beautiful radiators. If money was no object I'd fill my house with them. I'd like some 3rd party verification of the correction factors though.

I know. Thought it was only one room we needed to get rewired for cavity wall insulation but no... How does a "normal" house get its cables from the fuse board downstairs to upstairs? A wide chase above the fuse board, through the ceiling, then fan out under the floor?

I took off a wooden cavity closer by the bay this morning. Turns out it's not just the bricks in the bay that are soft it's the whole wall. Think the render is holding the wall up! A generous gap was left between the UPVC frame and brickwork, plugged with mortar(?). Look out for the daylight below! Lucky to have foam here, it's missing for most of the rest. The mortar-filled gap is over 2cm wide at this point. The out of focus bit is where the face of a brick has disappeared. To get a nice straight edge to the window opening they didn't cut cinder blocks to fit. Oh no, they took small ones, lined up the edge and left a couple of inch gap to the next block... covering it with plaster in the room. Despite the strong breeze blowing through and out of the cavity, it smells a bit - damp I think. I've temporarily stuffed HelloFresh insulation in the cavity. My plan had been to shove 100mm PIR in as a cavity closer but the brickwork is too uneven for a 100mm sheet to fit. Will rockwool do the job as well? And between the window and brickwork where there's the mortar and a little old foam: best to fill this entirely with foam, or does it need something more solid like chunks of PIR too?

Now it's cooling outside I am hoping internal RH comes down. It's remaining stubbornly high. Since all rooms are within 10% of each other I'm assuming there's not a leak in one room adding moisture to inside as I'd expect one room to be worse than the rest.

It was. The dew point would be about 12.5C with those internal conditions. Condensation was in the corners of the windows (more at the bottom) & across the bottom - thermal bridging via the aluminium spacers?