PeterW

You can do that now with a water level - two meter rules, a couple of lengths of clear pipe, a hose and some food dye. Works over as long as your hose and you can check via other doors or even windows.

There is a huge difference in quality !! Unless the B&Q stuff has had a marked increase over the past 12 months, its had real issues such as offset and strange sized flush and soilpipes, cisterns with bowed backs, shower trays that slope uphill, and a host of other problems that can cause fitting problems....! I know a couple of fitters who will now not fit B&Q or Wickes sanitaryware due to quality issues.

Exact same here - using EPS below the DPM and filling the cavity that way is a good method of reducing bridging.

@eandg seriously consider an insulated raft as these seem to get round a multitude of ground issues.

Thick door may not help that much but a lobby door would if you could move it so you had 2 doors at right angles. Got a dimensioned floor plan ..?

So it’s a workshop ..? Do you need it to be heated ..? This does make stuff slightly easier but also complicated in other ways ..! You will need to insulate the walls but tbh you could get away with just full filling the walls with Rockwool, and the same with the floor of the room above. Then clad with celotex and you’re probably reducing the heat loss a lot. If it’s an unheated space then still consider some insulation in the concrete floor but you can reduce it. This is purely down to comfort.

What I mean is that there isn’t that much to do, and whatever route you go, £20k should see you done and finished. Is the space below ie the ground floor room, part of the house or an unheated workshop ..? May make a difference for BRegs. Whats the actual purpose of the extension..?

You could do that for change of £20k.

No thats just DPM and pretty thick. Find a plastic membrane that is about 300 gauge.

They cap the plastic bolts from below the cistern. Bolt goes through the cistern, then the plate goes on below the pan and then the nut. Tighten up and the cap snaps on to cover the cistern bolt. Word of warning ...... Those plastic bolts are $h!te and of you do them up too tight they shear .... put a decent blob of CT1 / Stixall between the washer, the cistern and the head of the bolt inside and then tighten up. Usual reason for them shearing is someone trying to stop the bolts letting water past, and what you need is a decent seal with not too much tension on the bolt.

Get the engineer on board ASAP ..!! I’ve known designers come up with stuff that cannot be built (shortage of skyhooks due to Brexit...) and also people look at comparatively simple sites that end up with significant engineering in the foundations due to ground conditions. If you find a good responsive and reliable engineer, hold on to them for dear life ..!!

No ...! Not you... Read my post carefully. It is not a requirement to have a cavity, as in every construction must have one. There are build methods that mean you don’t need them , such as ICF, and even some timber frames use direct clad such as how @ProDave has done his. You could build a single block skin and then clad it with External Wall Insulation (EWI) and render that - perfectly legal to do so long as you meet building regs insulation levels. Not sure how easy or cheap it would be to do. Go back to my question though, what’s your budget as that could dictate the method.

Cavity is here : 2 x 50x25 battens at 90 degrees to each other and you have a 50mm cavity. You don't need a cavity anyway so not sure where you get that from. If it’s from a book, then it’s making general statements that aren’t correct unless it covers each build method.

@zoothorn if you want to change to cladding rather than render you would need to go back to planning. Whats your budget for this ..??

The answer to this, is this ... From the inside: plasterboard batten vapor control layer (plastic sheet) 145mm timbers packed with insulation OSB breather membrane vertical batten horizontal batten render board render Make sense now .??

Seen this a couple of times and tbh they don’t care round here as they charge you for the conditions every time. I would sell sell as individual units, anyone who wants to can go and get a new PP. What was the situation with CIL/S106 on the whole development ..?? That’s where you need to be very careful as the lot could end up in your lap.

TFFT....

Overlap of 30cm is fine - just use duct tape to secure the join. Not sure on your other comment though - can you put a drawing up as can’t envisage the wall build up.

DWB do right across the East Mids via MKM. Really good and they do a proper site measure when you’ve got walls to go from.

27mm is the thickness of the two lines on the page ...

Curves .... Measure straight to the corner you want, then measure from 2 other known points. Curves with a string line will intersect at the point you want, then check with a tape.

My mate has a piece of 6mm ply with a perfect single and double box cut in it, and stuck one of these on with mitrebond.

They are crap. End of ...! use it to mark the box by tapping with a hammer then use a multi tool to cut round the shape made.

@AliG what battery system do you run ..?? Makita LXT bare unit is the same price as that and a better unit.

Planning don’t care about this sort of thing - building control do.