ToughButterCup

Ok, I'll use a hole saw......?

And I need to learn from you. Loadsa spare 3mm ply, a table saw, and drill. Job done.

Thanks for the support. The thread on underboarding too early ( Woke up in a cold sweat ) is related to this one ; the advice @PeterW gave is the one I'd prefer to follow. (Place some 4 by 2 across the bottom of the rafters and butt the insulation up to that.) Recently I have been glancing at ceilings to see if I can detect the bumps made my the washers holding the underboarding. And of course, I hardly ever see any, because very few houses have underboarded rafters (I assume) - and I hardly ever get off the site. Nerd......

Build first - an exact number of blocks wide and high: no gaps for windows or doors. Might not be exactly 8 by 8, but it'd only be a few mm out....Then: Cut the gaps out with a concrete chain saw. Easy - (says the guy who doesn't even know which way round an insulation washer should be fitted ? )

Yes, Thats precisely what I will be doing (albeit at smaller scale) in a couple of weeks. Using a concrete saw, chop out the windows and doors after a reasonable interval. (2 weeks?). In our case we're chopping out a mis-placed window opening - moving it 300mm. Thinking a bit about your idea, if you were just a bit canny about it, and didn't mind non-standard size openings -in the case if Durisol- if you could cut a hole exactly in line with the joints in one layer, you'd only cut through half the amount of concrete (vertically) and small amounts laterally. Further, if you were to plan the tops of your doors and windows and drop rebar in one layer above, say two hefty bits per window and a bit more on a door - you'd be laughing! It would be interesting to do a roof in Durisol. Turn the blocks on their side, chop out the insulation, chop one side off and lay them as a set of soldier courses, laced up with rebar. Got me thinking now......?

Thats exactly what happened in our case. Bear in mind that the plot next door to ours was refused - at Appeal too, just a few months after ours was permitted. Both Politics and micropolitics are important

Yes. PHPP. But @JSHarris quick spreadsheet is as good and a much less Teutonic way. And I, first hand experience of the opposite. In general planners couldn't give a stuff, but I think it's fair to argue in certain circumstances, it does matter. It might even depend on the quality of the relationship between your planner and the planning official. And this aspect of sustainability has only just (last year or so) become relevant. So you'll need to be careful about that. Your wife is right.

I bet you've read this, but just in case......

That's normal. Prioritise. Develop a thicker than normal skin. Hold on to and remind yourself -often- about your successes. God knows, I mostly don't take my own advice. Warra eejit, eh?

Which is exactly why, after 4 bursts in four pours, on the last pour I was quietly physically sick behind the site storage container. And, by 6.30 that night, pissed as a fart because the final pour went off without a hitch. My signature mentions avalanches - it should also refer to grim determination.

I nearly swallowed my false tooth..... 10 lots of £415 (above) ... plant already on site...is £4150. And the final price is more than double that? Whas' goin' on ? It won't be hard to do a quick search on https://www.drainageonline.co.uk/ (there are loads of others) to get a general indication of materials price.

Referring to SPONS and local price experience ( NW UK) 10 - nearly 11. meters of 10mm steel, 203mm wide = £300 delivered Site welder £300 - check the quality of the work. Material handler (worst case ) £100 @jamiehamy : bang on - on as usual.

Well, for free stuff, that looks excellent. So, those screws go through the board, through the Celotex and into the joists / rafter?

Erm, 'normal'..... If you mean height, it'll be just under 3.0 meters

Cheers lad.... The idea of metal studs is attractive, but I have a bit more confidence with wood. Maybe next house......

In other words it's reasonable to do either; put the studding in first then insulate under the rafters and round the studs OR underboard all the rafters and then dig out where the studs meet the rafters Right?

Our roof design has 200mm insulation between rafters and 80mm underneath. With only a little bit of cursing and swearing I got three 80mm insulation boards up -on my own- yesterday. Vaulted roof spaces look sexy but they are sods to underboard. 0300 this morning : bububugger - I bet I should have put the studding in first - because that needs to be attached to the bottom of the rafters. And I've gone and hidden them now. Well, not quite. I can see where the rafters are because of the attachment points for the insulation. Those massive washers are a bit of a giveaway. Am I going to have to dig out the insulation where the verticals meet the rafters, or should I put the studding in first - and then underboard? Phhhh, 'nother steep learning curve I got myslef into innit?

That factor is so important. Unless you are a serial selfbuilder ( @Stones for example ) you are highly unlikely to be a repeat customer. Most of us here are ordering more wood / blocks / screws / plasterboard than we have ever done. But only a few grands worth. Once. And that's it. There's so much 'normal' work around that self builders have become the icing on the cake for a few tradespeople. SPONS is an excellent guide. But that's all - a guide.

You say potatoes I say patatoes. Interesting innit?

Could I suggest you consider using Solar PV rather than solar thermal? A little while back, I worked through the same questions as you are currently investigating. Just a quick site-wide search will bring up more than convincing evidence in favour of PV in relation to heating water. However, it would be useful to see if the technology for solar thermal has moved on since I looked into the matter..

Ok.... erm, why Gary? (sorry mate)

I'm putting 70mm of insulation under my joists. Using 100mm screws and insulation washers. Pesky little things insulation washers; they don't tell you which way round to attach them ..... Wrinkly side-up or smooth side up? Theres a bit of me which thinks that I should have the smooth side uppermost. But you know me and thinking about stuff. Too much too often. Does it even matter?

We can guarantee noise because of ice movement on our flat roof. It took ages for me to reassure SWMBO: the sound is close to an air-rifle shot. Off putting.

Well if he wasn't, he sounded as if he was. Needed SmellaVision to be sure really.......

Welcome. Busy then?