Temp

For a single zone set up you have one stat connected to all of the actuators on the UFH manifold. If some rooms overheat you can potentially adjust the flow to those rooms (balancing). You could also consider running the wires to allow extra room stats to be added later. 1mm^2 or 1.5mm^2 wire is normally fine for the stats. There should be instructions with the wiring centre but note some are designed for 12V stats and others 230V. Some fancy systems can also transmit data to/from the stat and might need an extra core in the wire or use CAT 7 cable instead. If in a rush I would install 3 core and earth mains cable as that can cope with most basic stats/programmable.

May have to get the court to amend any order.

Might be necessary for Building Regs Part E sound transmission?

Unless your deeds say it must be a wall I believe you could replace it with a fence.

Needs a proper survey.

I dont see why they wouldn't install a supply to your plot. You're going to need a temporary supply anyway.

Welcome to the forum and good luck with the planning application.

I think you would have to write to the company, give them opportunity to rectify within say 14 days or else you will consider them in breach of contract. After those 14 days write again to tell them they are in breach of contract and you will use the retainer to fund the repairs. Send letters recorded delivery to the registered office and the reciever. Keep copies. You probably should get several quotes for the repairs to show they are "reasonable" and don't include anything not a repair in case they are ever questioned. I'm not a lawyer.

We have burst watermains about once a year in our area. Think they are asbestos cement and it cracks when the clay moves.

I wonder if you could find a private BCO who would give an opinion on the suitability of the slab (for a hours fee probably).

Think I'm hot on the trail of the problem. Found installation instructions for both mixers and they BOTH have non-return valves built in. So mighty relief as unlikely I will have to bash holes in walls after all. The flows are balanced, all mains pressure and near identical pipe runs. However the hot goes through a heat exchanger on a thermal store. Water from the store is circulated through through the other side of the heat exchanger by a pump triggered by a flow sensor on the cold pipe. Eg open a hot tap and the cold flow starts the heat exchanger pump. Annoyingly the issue seems to have gone very intermittent. I was able to trigger the fault once and check the flow sensor was calling for heat (it was) but it started working again before I could check if the heat exchanger pump was running. I'm leaning towards the pump or the supply to it being the cause but need it to fail more repeatedly to fault find it.

I've just discovered one of my shower mixers is supplied with non-return valves built in so perhaps I'm barking up wrong tree. I'm going to have to do some more fault finding.

Just a heads up... Recently finished a second bathroom in our house and turned on the isolation valves for the shower. At first it appeared to work well but after a few mins the water ran cold. Its done that several times and it's not an issue with the boiler and tank running out of capacity. I need to confirm this as the cause but I have a horrible feeling our plumber didn't install any one way valves. So at an unused shower it looks like water is flowing from the cold feed through the shower mixer and back to down the hot pipe, then to the shower in use. If that turns out to be the problem it's going to be "interesting" getting access to the pipes to install four one way valves as both rooms have stone tiles. I also think all four pipes are 22mm copper and run super close together in a stud wall so getting 22mm compression fittings in might prove a nightmare. Oh joy of joys.

If measuring the flow out of a pipe without the funnel take several velocity readings over the area of the pipe outlet and average them to give an average velocity. Then use the cross sectional area of the pipe in the calculation instead of the area of the anemometer. This is a little inaccurate because of the way you calculate the average velicity should be area weighted. There is more slow speed air around the edge than high speed air in the middle of the duct.

m/s is a linear velocity. L/s is a volume flow rate. To convert between the two you first need to know the cross sectional area in m^2 (aka sqm) where you are measuring the velocity. In your case you are funnelling all of the air through the anemometer so that's the area you need. The radius is 3.25 cm = 3.25 * 10^-2m. So the area = Pi * (3.25 * 10^-2)^2 = 3.32 * 10^-3 m^2 The flow rate in cubic meters per second is then the velocity (in m/s) * the area (in m^2) So let's say the velocity was 1 m/s... The flow rate in cubic meters per second would be.. 1 * 3.32 * 10^-3 = 3.32 * 10^-3 m^3/s To convert that to L/s multiply by 1000 because 1m^3 = 1000L So in your case with the funnel .. 1m/s = 3.32 L/s

I just had a look at the lot20 stuff because I might also need to replace some in a flat. Talk about confusing. They appear to consider electric heaters about 33% efficient (perhaps because ASHP have a COP of 3?) and then allow you extra % credits for having fancy controls like open window detectors. I wonder what jobs worth thought this scheme up.

Yeah Openreach told me something similar, I would have to have an overhead line etc etc. We ran the right wire to the bottom of the pole underground when we did the electric and the engineers that (eventually) came to install our line were happy to use it. Local companies that sell duct usually know what the DNO want. Eg must be smooth bore solid duct not twin wall. 3/8" polypropylene draw rope.

Not when we built. Most were ok with being paid in stages in arrears with 5% retained for snagging. Our builder did ask if I could help with cash flow once and I agreed to buy the windows myself.

Just make sure the sand can't be washed out at the edges?

It is when on load but I was thinking more about the losses running the inverter in a standby mode waiting for a load.

Yes If its not moved in 10 years should be fine.

They could probably eliminate the delay by running the inverter constantly but that might waste more energy. I suppose some types of load might also cause the inverter to switch on and off rapidly if the response time was too quick. I suppose that might put a lot of noise on the supply?

Have you moved I yet? The forms ask for the move in date. Started paying Council tax? HMRC really don't seem to understand self builders. They like to think people finish their house, get Building Control Completion, then move in. Any other sequence seems to be a grey area. So if you haven't moved in yet its should be safe to assume you have three months after BC completion. If you have moved in there is a risk they may decide your move in date was the effective completion date. So three months from then. Anything else you might need to justify.

DPC can be Hessian & Bitumen. If you can lay coping stone on a DPC as per the NHBC drawing I think it should be possible to lay them on bitumen/felt. Google found this page recommending a mechanical fixing but I've not done coping myself.. https://www.roofgiant.com/blog/news/how-do-you-secure-coping-stones/

Perhaps ask him what he thinks of the insulation requirements of the Building Regs? Don't say any more but note if he see it as an expensive regulation or inadequate target. If you are going for ASHP ask him what he thinks of them. He should say something about them working well if you have UFH and a well insulated house. Ask him if he thinks airtight houses are unnecessary. Hopefully he will tell you its important. If you are on a self build mortgage that has strict stage payments you might want to sound him out on what stage payments he normally wants. It's not a great idea to agree exactly the same schedule with the builder as your mortgage lender but they must be compatible schedule's obviously. Perhaps don't tell him what they have offered you. You might want to negotiate more favourable terms with the builder so you retain a bit more to the end. It's not unknown to retain a percentage for a year after completion to cover snagging. Ideally find out where he's working at the moment and go look at that house. Is the site tidy? Neat work? Messy? I've said it before - If you ask him to take you to one he's built it will probably be his mother's house 🙂