Mr Punter

Where we are (Sussex) the electric people insist on smooth ducting - 32mm single phase, 50mm 3 phase.

Does the trench go right up to you house? Is the water level anywhere near the underside of your floor? If there is some sort of spring it may be good to intercept it higher up and divert it outside your house footprint, assuming you are on sloped ground. I can't see why the water co would care unless there is nearby contamination in which case you should use barrier pipe. I would be tempted to line the trench and pipe with building sand as gravel may have a french drain effect.

Probably the neatest building site I have seen. Manifold looks very, timber frame with double noggins. Did the architect detail where the windows would go in relation to the frame and external cladding? It is an easy detail to slip up on, but simple enough to remedy. Are you on a deadline which must be stuck to (tenancy ending or whatever)? If not, just award the project another few weeks and give yourself a pat on the back for what looks like a first class job.

...and maybe change out of the profile picture outfit on the day?

It could be that they are a fairly small outfit and will not be willing or able to represent or defend themselves, in which case straight to court. You will still need to prove your case with evidence to the satisfaction of the District Judge (or whatever they are now called).

Sorry - I missed that. If they have the same strength and stiffness, chose the one that is cheaper. I guess the 18mm is lighter, which may make it easier to install if you are doing it on your own.

Go for 22mm lay at right angles to the joists. Normally try and lap the end on a joist and stagger the laps by half a board. I like D4 glue on the joists and on the tongue. Screw the boards down.

Not sure of your supply pipe. We have a sprinkler system at mains pressure and achieved over 100l / min at the inlet valve, so <10 mins for your tank. A couple of months ago before the pipework was properly secured and boxed in one of the kid's friends opened the front door and the handle hit part of the valveset and caused a fitting to come apart. It took about 2 minutes to shut off, by which time the ground floor of the house had about 5-10 mm of water throughout.

11mm feels much stiffer and the price difference is v. small. If you OSB it may be prone to mould. Some of the MGO can be left without even painting the underside.

Magnesium oxide board (MGO board) might be good. It will stiffen up the roof a fair bit too. Water and fire proof.

You will need access at the base of the stack up to the main run plus access to rod the main run.

This is very difficult to work with without specialist equipment. We did 50m in 90mm O/D for a pumped application. Even on a hot day it took some serious wrestling before it could be placed in the trench. Also you have the issue of connecting the ends which will make it far more trouble than it is worth.

I would only run drainage under the slab where it was not possible to do otherwise. If you can achieve a min 1:80 fall by running outside, do this. You can change direction with an IC. The biggest financial risks in housebuilding are foundations and drainage.

Make sure you have a starting point for negotiation, such as a request for the supplier to fully refund you and (if you want to try it on a little) additional damages for delays and project prolongation. Stick to your original claim and then wait for the other side make a counter offer. Don't start with offering to re-purchase at cost, or you will have nowhere to go. The mediator does not look at the merits of the case or report to the court if mediation is not successful.

I like the base of the stack radius bend supported on the foundation on mortar / concrete. You can support the pipework by suspending from the beam and block, but I would want to see stainless banding for this https://www.toolstation.com/shop/Construction+Materials/d210/Builders+Metalwork/sd2797/Stainless+Steel+Banding/p48657. 6m max for pipework because plastic expands / contracts and 10m is impractical.

We did seven townhouses, all a bit different. The test guy picked one (end terrace) and tested it. It passed easily (3.74 against 5.00 required) but I was quite surprised when he did not test the others. Fee was £690 and the guy was on site for about 2 hours. I imagine they just extrapolated the results over the remaining, which all got a slightly worse score.

I have not had any issues with this. Is it Permitted Development for Office to Residential where you have prior approval? If so, send a copy of the Prior Approval to the Valuation Office and request that the building is removed from the rating list.

The 150 DPC rule is to help prevent the bottom of the wall becoming saturated from rain splashing up. If it is only a small section and it is not facing the prevailing wind you should be OK. Sometimes you can just have shingle up to the wall to reduce spashing

OK @epsilonGreedy I hope we may have persuaded you to look at timber frame again. Have you considered whether a passive slab foundation may work on your site? Better insulation, less muckaway, no deep trenches, no sub floor ventilation and a clean level work area early on.

Hi @Tosh Hello and welcome. Everyone here is keen on photos, so don't be shy with them. This sounds like an interesting scheme. There are lots of members who will happily give valuable advice - just ask away. Some are a bit nerdy but don't let that bother you.

@epsilonGreedyHaving read a number of your posts I think you should look again at timber frame. It will mean more likelihood of weathertight by Xmas and you can build the brick skin at your leisure.

Hello and welcome! I think you will need proper joints such as mortice and tenon or timber connectors. The surrounding joists may need doubling up as well.

The Aga will make it sweltering.

If you need a warranty, get it sorted now. They like to inspect foundation trenches. Xmas in the dry is admirable but ambitious. Don't kill yourself over a self-imposed deadline. Have you got someone to help? Setting out, concreting, drainage and ducting is far easier with two people, especially if one of you has done it before.

More likely the battens or rafters have shrunk or twisted or a fixing or slate is broken. When you buy your slate, make sure that they are consistent thickness and straight grain. Get a stack of about 12 and see if they wobble when you press the corners.