Sparrowhawk

How thin can you get away with? 15mm batten + 12.5mm plasterboard (+ 3mm top coat if not tape & jointing)? We need to rewire external walls prior to CWI and I am not looking forward to having runs chased out in a lived-in house.

After stripping the (dry, wooden) surround off I've found two leaks on the right side of the downstairs bay window, and I suspect it's the same the other side. Where the window sill has been cut into the brickwork it has been leaking for a while - the render is soft, the wooden packer has rotted and the brick under the window is soaked. The open cell foam filling this area is sodden. Before storm Ciarán hit I filled the cracks and places where the mortar fell out with CT1 as it was soaking wet, which didn't stop the water coming in. During last night's storm I found a leak at the top right. And now a third leak between the bottom of the window and the sill. 2 questions: How can I patch this up for now, and what is the long term fix? We're planning to have this wall re-rendered due to cracked and crumbling (sodden) render, but this looks like a weak spot. With the gap between window and wall, and the way the window sill disappears into the wall and the open angle where the render touches the UPVC is going to be tricky to make waterproof? Overview Bottom right With my new CT1 trying to fill gaps. Foam is supporting external render. Some of the render fell off and I could feel sodden foam. Top right Again the old foam added to try and stop/hide the leak? Foam is probably supporting the render. And the bottom:

Having bought a new can - it wasn't the propellant. The first can was fine. The needle moves with no issue in the gun. Somewhere between where the can screws on and the foam reaches the needle it has gone solid.

Let me introduce you to... Gapotape! In all seriousness I'm making the same decision for our suspended floors. Probably going Rockwool but whatever's cheapest (so long as it's not glass fibre) as the airtightness will have a bigger impact on our comfort than more insulation. Loose wood fibre is appealing because it can fill all gaps and is easier to push into hard to reach areas.

Welcome! I've two friends in Malvern/Great Malvern and it's a beautiful area. There are loads of threads and discussions here on ICF and the different systems so do have a search of the forum. Some cover the "greenness" of it and the hemp versions too. I'm renovating a poorly laid out and twice-extended house so my first question to you is: do you have the money to knock it down and rebuild? 🙂 If anything's load bearing inside (all our ground floor walls are) or you've got internal cavity walls from before the extensions, it's hard to sort the layout. We've given up and are making the best of it. Plus you can get airtightness, insulation and comfort right from the start. Good luck and do share your progress!

I'll push back and say that it does matter if your windows are smaller, as you end up with less light. Both a small window and a set of UPVC french doors have 40% of the opening as UPVC and 60% glass. It's most noticeable with windows on the north side of the house.

I've enjoyed dipping into this Norwegian build: https://www.youtube.com/@mindsparx1/videos to see the way a carpenter orders the tasks.

Facebook marketplace. If you have a vehicle you can pick doors up in, you can get a set for under £50. Or free because people can't get rid of them. Depending on your house size you might need 2 sets which won't match, but they'll tide you over. I got a still-shrinkwrapped Wickes £30 door for free that way.

Am I correct that when working out the floor area for Part F F1(1) 1.24 it requires the following? You must include the whole area of a room in the eaves (even if the headroom is under 1m) You must include the area taken up by walls You should include anything inside the thermal envelope e.g. eaves storage cupboards And because of the emphasis of supply of air to habitable rooms, which Part F defines as "A room used for dwelling purposes but which is not solely a kitchen, utility room, bathroom, cellar or sanitary accommodation." I exclude the floor area of our kitchen, utility room and bathrooms?

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?