Tony L

Sorry. I should not have insulted you. I'm careful not to antagonise or upset my friend as I try to steer her away from the information sources that inform her world view & I should have taken the same approach with you.

This is what my friend, Rebecca, says. & she knows a thing or two: she explained to me how the moon landings never actually happened – the US government paid Stanley Kubrick to film them in a studio. & did you know con trails aren’t just water vapour? They’re biological sprays or something that the government use to control us. Something like that - I don’t really understand. I bet @Spinny could explain it to me.

About 5.3m wide & 6.4m deep (external measurement for the slab). I'm planning a ring beam, hung off screw piles then I'll build up the middle with hardcore & 70mm crushed concrete, non-woven membrane then sand blind the middle, get my DPM in, tape it up to prevent leaks around the screw piles & joins (self compacting concrete leaks almost like water, I have learned), rebar mesh on some castles & tied to the screw piles so it doesn't float, then I'll have some ready mix SCC delivered. I'm thinking a chute will do - I don't want to pay for a pump. I'm expecting the SCC will just flow to where it needs to go & won't require too much work to push it around. I could tamp using the top of the shuttering, which I will set with a laser, but I don't think tamping will be required. For SCC, I know I definitely shouldn't work it with a poker, as this would ruin the homogenous nature of the mix, & weaken it considerably. I've decided to forgo a layer of insulation in the slab, so I only have to pay for one concrete delivery. A while ago, I worked out that mixing this volume of concrete myself would not be any cheaper than ready mix (for ordinary concrete), & I'm expecting the SCC to be around £300 more than ordinary concrete, whilst saving a lot of bother. I have very little practical building experience, although I have succeeded in making two concrete garage bases, most recently 20 years ago, & not with SCC, so any critique of my plan will be most welcome, please.

Thanks for bringing my attention to SCC, @Nickfromwales. @flanagaj, according to a conversation I had with Gemini AI, you'd use a dapple bar, rather than a bull float with this. Based on watching one YouTube video, it looks like an easy enough DIY job for my small garage, although I think I'd be inclined to to pay some experts to do this for me if this was my house. The sealant, which goes on soon after the pouring & dappling, is super important.

Very well done, @Captain Scally.

Is bare OSB, or even painted OSB a good idea inside a habitable room, especially a garden room, which could get very warm inside during the summer? I'd be looking into the possible harmful effects of VOC off gassing if I was considering this.

I was thinking I would do the same (assuming I ever get that far with my build, which is not going well) although I am also intending to have a soft outside tap for car washing. The water is very hard in my area.

Yes, although, it can lie a little bit, if half a hose is in the shade & the other half is left in blazing sunshine like we're going to have over the next few days. But it's easily checked, by bringing the two ends of the hose together.

Or have some lovely steps at your front door & make your Part M level access at the back door.

Agreed, @Mr Blobby. That's a good improvement on the computer putty coloured one above. I've always been surprised at how very ugly most of these units are. I suppose the designers have mostly spent years designing units for commercial buildings & ugly is cheap, & it doesn't matter. It hasn't occurred to the designers that their creations blight the appearance of so many homes & many people will pay more for a competitor's less ugly design. Same goes for MVHR units; Zehnder have some nice looking designs, but if I choose something else, I'll have to build a cupboard around it.

This has been my experience so far. Good for you. Show no mercy.

& the current era as well, if the builders & architectural technicians I have employed are representative of today's building industry personnel.

I'm sure you could find out, easily enough. I know where mine is, & it's not very far away, so a personal visit would be easy for me. My approach wouldn't be right for everyone, of course. I don't mind inviting myself into somebody's office & making a nuisance of myself. Sometimes it works; sometimes it doesn't. @BTC Builder. If it's any consolation, I am quite envious of your problem. I think I am years away from sign off stage, & I expect to be badly let down by many more people and organisations before I get there. You're at the last hurdle. Well done you.

I would go to the council office & be reasonably polite, & very, very assertive.

Thanks, @DIYMichael. I like the look of the Base Camp masks you recommend, & I've just placed an order. The Makers Manual discount was applied automatically at the checkout - thank you.