ProDave

Cue them to say "from this stage you should be able to complete in 8 weeks so that is when we start charging CT" I am glad I have not had this nonsense, I have been building for 5 years. On his last visit the CT inspector got a few feet in from the front door and said "you don't have any doors on yet, I can't possibly value it yet" The alternative stance is to say yes it's "complete" but it is only half the size that was shown on the plans so value it as a bungalow, and then have cheaper CT for as long as you live there.

There is nothing like calling a spade a F shovel is there? Astonishing.

The site supply needs to be far enough away so that it is not in the way for scaffold, diggers and other works so 10m seems a good distance.

All your electrician needs to do is connect a few waterproof sockets. Remember to connect them to a TT earth (local earth rod) If the builders want 110V they will bring their own transformers. A couple of 16A "commando" sockets would be handy as well as standard 13A sockets.

Post some pictures of the controls, piping, hot water cylinder etc. Then do some basic checks and (with reference to the pictures) tell us what pipes are hot and which are not. Also include pipework and controls relating the the heating side of things which at the moment should all be cold. If there are any thermostats or thermometers on the cylinder for instance tell is what they are set to or what they are reading. I fail to see how antifreeze can "clog" a pipe. It is a liquid. Even when poured in neat it will soon mix with the water to give a dilute mixture. I suspect this was a BS excuse for "I have not got a clue, I messed about without knowing what I was doing and I think it is now working"

But I turned off the resistance heating function in my ASHP because I could see the flaw. It did something like heat the water to 45 degrees with the ASHP then heat it further to 55 degrees with the built in willis heater. The "issue" was as the water cooled down, the temperature sensor would say it's gone below 55 degrees by it's hysteresis setting and turn on the willis heater. It rarely went low enough to trigger the ASHP to "pre heat" it, unless you ran off the whole tank of water in one go. I now heat it to 48 degrees just with the ASHP function.

I would go down the lawful development route. Can you prove how long you have been using it? i.e a receipt for when you bought the shed? When you submit a planning application for land you do not own, you have to serve notice on the owner that you are doing so. Can you find the owner from the Land registry? Then serve notice on whoever is listed. If they have gone bust, someone will have "inherited" the land as part of dividing up the assets of the insolvent company.

This is usually the point where your wife says "oh the kitchen is not tiny after all"

My issue is HOW does that work? It would have to rely on the return temperature being very low, so the ASHP could heat it first then the oil boiler top it up. That would imply a very low flow velocity, which is exactly what an ASHP does not like. My concern is the ASHP would only end up working in the initial stages of heating and once up to temperature the oil burner would be doing it all. I would love to hear how these work in practice. Regarding which heat pumps to avoid. Just make sure it is INVERTER driven, so it can modulate it's power to the actual load.

Of course the time to have decided this was before you started. My suggestion would be square off the boundary so you gain a bit and lose a bit and the net transfer of land is nil.

I am willing to bet if you shop around, you will get an ASHP for no more than cost of an oil boiler plus oil tank plus fire valve plus oil pipe etc. Oil boiler needs (or at least should have) annual service. Just choose over sized low temp radiators upstairs or UFH upstairs, Or like many of us you might find with a well insulated house, no heating is needed upstairs.

What has put you off an air source heat pump? The price of oil, while cheap just now is too volatile for my liking. And they are noisy smelly things. I don't think anyone has ever explained how the hybrid combines ASHP / Oil boilers work. how do they handle the transition to ensure you are not just burning oil? It's hard enough finding someone that understands an ASHP, it must be harder finding someone that understands a particular make of hybrid.

Then that sounds a reasonable price to pay. Consider the uplift in value of the land if you can get PP for a house. But I would want an absolute upper cap on his fee, not a completely open ended agreement.

What is your proposed "1.5 storey building"? A new house? Or just a residential outbuilding?

My Telford does not lose enough heat to cause an over heating issue, even in summer. At only 48 degrees water temperature, I suspect the real heat loss is less than 2.3kWh in 24 hours. And remember for half the year, that "heat loss" is just helping to heat the house and we don't have much in the way of actual heating upstairs so is quite probably beneficial. I suspect a lot more heat loss is caused in many cases by poorly lagged pipes connected to the cylinder. Note the pictures of my cylinder in the other thread are before all the pipe insulation got fitted.

So that gives even more possibilities, like he could re draw the boundaries between the 2 properties enabling you to square off the extension.

You will see from that thread, I chose the Telford HP cylinder with the large area input coil. The large area input coil is important for use with a heat pump to get good heat transfer into the tank from the input water that is not much hotter than the target temperature. Standing heat loss is a separate issue, though in an ideal world you would find someone making a cylinder with a high area input coil and A rated insulation (let us know if you do)

The point is, if he wants the extension as wide as possible this should have been agreed with the neighbour first and the fence taken down to facilitate that. If the neighbour chooses not to put the fence back he could gain a few inches of garden for his good will.

It it is your father on the other side of that fence (if I read that right) I would have got his agreement in writing to build ON the boundary and would have taken that fence down to facilitate that. You would also need permission from your father for the eaves to overhang. Or at least with the fence gone you could build close to the boundary so the eaves overhang stops on the boundary.

The only place my drawings specified fireline was in the attached garage, as two layers with staggered joints.

I would be questioning why the drawing calls for fireline throughout. That is not normal. But I would want to be sure before I ignored that.

We only once so far have noticed a "bad smell" via the mvhr. It was on a summers morning, you know those mornings when it is absolutely completely dead still and a low mist was hanging over the valley. The house just smelled "stale" I went outside and it smelled even more stale out there. It was that "dirty dishwater smell" The culprit was next doors septic tank not far from our boundary filling the still air with a septic tank smell that just lingered. It's not often we get still air for long enough to cause that sort of problem.

No taping of nail holes. The theory is it is not a problem, unless you pull a nail out and then leave an open hole. The OV10 vents I used are supposed to give a ventilation area equivalent to a continuous 10mm gap. the vents are somewhat thicker than 10mm but I don't know by how much. All my OSB is just nailed. I used a 3mm gap because like you I was not sure.

Yes when heating DHW the HP runs at full tilt most of the time, unlike when heating the house the compressor and fan runs much slower. The HP is just outside a small living room window and that is the only time we can hear it at all inside. The default with mine is to only run in DHW mode for half an hour at a time (you can change that) I speculate that is either to reduce risk of icing, or the designers were worried if the space heating was off for more than half an hour at a time you might notice it (you would not in our house) A typical day when you are only re heating what has been used it will get the tank up to temperature in one half hour cycle, but if the ladies have both had a "hair wash" shower, or a bath, it will take longer. This week, which has been a pretty grey and quite wet week, so poor solar PV generation, we used 15kWh heating DHW with the heat pump.

Ah so the bales are not actually supporting the roof load. The one and only straw bale house I wired had 2 timber frames, one inside and one outside with the bales in between. So the bales were literally just insulation piled up in between. the exterior cladding (timber) was fixed to the outer frame and the interior service void and plasterboard was attached to the inner frame. If yours is being lime plastered inside directly on the bales, I would love to see what you are doing with wiring? All in conduit I assume, but how do you fix a socket back box to a straw bale?