hanvyj

We have a 70s property with cavity walls (cavity insulated) and suspended wood floors (uninsulated). The kitchen is a mess so I'm planning on renovating that, as part of the renovation I'd like to insulate the suspended wooden floors, and add UFH (being able to remove the rad for counter space). In the future, I'd like to insulate the rest of the floor, and I'm considering external wall insulation (depending on the cost). Until we insulate and add UFH, an ASHP wouldn't be a great fit, I don't think. By my calculations it would more expensive than the current oil boiler. But I'd certainly like to get an ASHP or even GSHP in the future. I'd be doing all this DIY, so my plan was to slowly upgrade the ground floor to be insulated & maybe install UFH throughout while still using the oil boiler, then make the switch. I've read that UFH doesn't play well with a boiler however. Would it be sufficient with Thermostatic Mixing Valves for each loop - or would I require a thermal storage tank? Would that then have to be removed if I ever installed a heat pump that naturally operated at lower temperatures?

I hadn't originally planned to, but I'm certainly going to put one in now yes.

Hi, I was just boarding my garage roof with OSB and a builder next door told me that I might want to be careful for condensation as I'm using insulation between my joists. Here's the construction as I've currently got it planned (at the moment I'm laying the OSB. Some insulation is left over EPS, some will be rockwool, if that matters) I'd planned it with a ~68mm ventilation void above the joists, as I'll be adding counter battening under the steel roof itself, but hadn't considered if the 11mm OSB would be vapour permeable enough. Here's the general layout: Does this look sensible?

Converting it to a solid floor - would 100mm or so of concrete not be needed? Hardcore -> eps insulation -> Concrete I just DIY poured a concrete slab for a garage I'm building with the same set-up. The concrete was costly! I suppose it just replaces the screed in the original plan.

Hmm, interesting idea. I measure 460mm to the top of the joists. So the amount of insulation needed might be costly. The floor looks to be sandy ground, with a few bits of broken brick here and there, haven't dug down to see what it's like. Floor is already pulled up to fix a leak. I'd be doing the work myself - would I need a structural engineer or building regs involved? Presumably wouldn't with just joist-insulation. I'll consider insulating the rest of the property in the same way at some point. Floor plan: Green area is the area in question, we're planning on knocking down the wall and extending the kitchen into the hall: The ground:

Yes by screed I was thinking weak sand and cement mix like you describe, sorry if that was the wrong word. I've seen an 8-1 mix recommended e.g: https://www.centralunderfloorheating.com/underfloor-heating-installation/underfloor-heating-screed.html Yes, 100 doesn't feel like enough to me... that leaves me with option 2 - or I could use thicker insulation, like the 200mm eps I have and leave the joist bottoms open to the air?

Just had a burst pipe under the suspended timber kitchen floor and need to rip a load of stuff up to fix it. I'd like to properly insulate, and also fit underfloor heating while I'm doing the work. We might have to get a heat pump at some point in the future, and having no radiator in the kitchen would mean we could have a much better layout etc - so while I'm ripping flooring up and fixing plumbing, I'd like to sort out the underfloor for the long term. The joists are 5 inches deep, so would maybe fit 100mm of PIR insulation + a space for screed. However, I've seen people recommend rockwool on top of a dpm e.g. here Would it be a bad idea to have insulation under the joists - this would reduce them acting as a cold-bridge, but they would no longer be exposed to the air to keep dry? 100mm is less than I'd like. Options I'm considering Curious what people's thoughts are. Edit: I also have a bunch of spare 200mm EPS. I'd love to be able to use that!