Temp

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 🙂

The data for the LED on Aliexpress is confusing. It could be 12V DC, 12V AC or 12-24V DC. However one of the photos is a diagram showing how multiple LED are connected. This shows a 12V DC transformer. It also shows the LED wired in parallel. So I think it's most likely to require a 12V DC voltage (possibly 24V DC) and very unlikely to be a constant current type. With a constant current type LED you would either use one driver per LED or possibly wire multiple LED in series not parallel.

Another possibility is a Quantity Surveyor but you would have to pay them to work out the cost.

Is it possible they measured the opening in the blockwork rather than the frame the windows are fixed into?

Is he the sort of family friend that comes to dinner and might see them again? They look like freestanding wardrobes that have been built off site and fitted. If you really can't live with it you could probably find someone to move them towards the chimney and put an infill on the other side.

Architects and QS are quite expensive. Their standard contract can typically ask for as much as 11% of the build cost each if you hire them for the full duration of the project. If you can afford that then great. The Architect would visit the site regularly to check progress and manage the builder and look for defects etc. The QS would also visit a few times to value the work done and tell you if it's OK to pay the builder the next stage payment. Having a QS on board can help if you expect a lot of changes or the builder starts pressing you to pay more or in advance etc. It can be handy to be able to defer to your QS. However if you are good at managing people and negotiating then perhaps you only need an Architect and QS at the beginning? If unsure perhaps hire them in phases? If the report submitted for planning says underpinning isn't required I would start by finding an Architect to do construction drawings and get Building Control Approval to start. The Architect may require the services of an SE to check some things. Some Architects seem unable to do the calculations for steel beams for example. Be very clear on your budget. Its very easy for them to design things you can't afford to build. Depending on how that first phase goes you can decide if you want to pay for an Architect to be managing the build or just be available on an hourly basis. Do you even get on well? Start looking for builders. Any nice house you see being worked on stop and tell them you might need a builder and ask to look around. The more sites you can see the better. These unannounced visits are better than getting the builder to take you to see one finished- that one will be his mother's house 🙂 Look to see how tidy the site is. If the plumbing is in are the pipes neatly laid out or a mess? What are his views on the level of insulation required by the building regs? Does he see it as a pain to meet or an inadequate target? What does he do to ensure the house is air tight? Has he installed MVHR before?

Caution... To be eligible for Class Q Permitted Development I dont think you are allowed to underpin or replace foundations. Normally the planners require a report confirming the building can be converted without major "development". I would look to see whats in the report that was submitted with the class Q application. If it mentions underpinning in there you might be OK because the council gave approved it anyway. If not mentioned then you might have to hope the planners don't find out you need it. https://www.edgarchitecture.co.uk/blog/what-is-class-q-planning