ProDave

At 400mm centres you frame around the opening probably needing doubles on at least one side of the opening. Regarding C16 vs C24, I was building my decking frame recently and accidentally found if I ordered 6 metre lengths they were all C24

There is unlikely to be any damp proof membrane under the concrete of that sub floor, so it is probably just ground water. That is why under floor ventilation of that type of floor is so important, so check carefully all the air bricks are free, not blocked, and most importantly, not covered by external ground level that has been raised too high and is blocking them.

We have a frght mixture of upstairs ceiling heights. The whole roof structure is hung from ridge beams so all rooms could be vaulted right to the ridge if wanted. But we only did that with one room, which has a mezanine above the adjoining small bedroom. Landing and bathroom we did a normal 2.4 metre ceiling to give us a just about standing headroom bit of loft space. And the master bedroom we did with a 3M ceiling height still giving us a feeling of most of the available height, while giving a further bit of crawling height loft space access via a step up from the main loft. If you want smaller joists to preserve headroom why not fit more of them at 400mm centres or even closer? At 400mm centres I used just 12mm OSB as the loft flooring to preserve headroom.

What I learned in my first self build (ordinary insulation levels no mvhr) is heating in the hall, and definitely on the landing was not needed. As stated up the thread they are "rooms" with little external wall and borrowed heat from other rooms, and in short the UFH never came on in either the hall or landing. Second self build I did not waste the time and effort laying UFH pipe in either the hall or the landing.

Good news. Just be aware the cupboard it is in may well be lined with Asbestos cement board, so get that checked if you plan to modify the cupboard when it has gone.

Sounds a positive step, but the devil is in the detail and as we don't know that it's impossible to say if it will be any better. Lets hope so.

Welcome back. We obviously don't know the details of why you stopped. That is personal that you may or may not want to share. All I can say is be positive and flexible with your plans. It would be a huge wrench for me not to complete. In our case it was unforeseen financial circumstances that forced a re think, and our revised plan was a very much slower "build as you earn" build with us doing far more of the work that we expected to at the start, but we completed and are now comfortable in our new house, and the eventual sale of the old house that caused all our problems actually left us better off in the end than we ever expected. So chin up, formulate a plan B and move forward.

If you do a proper heat loss calculation, e.g use Jeremy's spreadsheet available on this forum, it calculates the ventilation heat loss properly. If the MCS calculation does not do that, then it is flawed. Why do we tolerate a system that specifies a heat pump size without calculating it properly?

I have a contrary view on plant rooms. There is a trend to put everything together in one plant room. But is that the best thing? Not always. It was brought home to me when I wired a friends house, a plumber, and his plant room contained all the usual things, the mvhr unit, the manifolds for the UFH. the consumer unit and the hot water tank. Shame was, this put the hot water tank at the diametric opposite corner of the house to the kitchen and main bathroom. I similarly had a "plant room" designated in the room above the adjoined garage. But as it evolved, the only thing in there is the mvhr unit, and a few of the heating controls and a pump. The rest of that room is now my workshop / office. The HW tank is in an airing cupboard in the corner of the spare bedroom, giving it the shortest hot water route to all the taps. The UFH manifold is in the utility room putting it central to all the UFH loops. The plumbing manifolds are under the floor under the bathroom with access through a ceiling hatch in the utility room below, optimised for shortest hot water pipe routes. Consumer unit is on the wall in the utility room for convenience. All network and AV gear is in the cupboard under the stairs optimum position for short AV cable runs to the 2 main televisions. It just made no sense whatsoever to try and put all this in one place.

I am so glad NOT to be a landlord any more.

On the 3 heat pump installs I have done for others, I recon 2 days for the plumber and electrician so calculate that at your local rate, plus parts. Assuming you are going to have wet UFH anyway and a hot water tank, it really comes down to difference in cost between a system boiler and tank, or an ASHP and tank. There is not much difference to install in a new build. Or will bur BUS grant subsidise installation of UFH on a new build as well as the ASHP?

Definitely something odd here. But we don't know the details of your "well insulated" house. For another comparison my 150 square metre house has a worst case heat loss of just over 2kW for the whole house when it's +20 inside and -10 outside (a realistic winter temperature here) and is heated fine with a 5kW ASHP. There is a spreadsheet available on this forum that if you care to try it and input all the details of the house will give a very accurate idea of heat loss. I found even the detailed full SAP with all those same details over estimated the heat loss by some margin. Also if you do have a heat loss of say 7kW, then you will need more than a 7kW ASHP otherwise it would have to spend all it's time 24/7 heating the house and would have no off time and no time to heat your hot water.

Usually loose terminals. There will be a lot of current through that for 7 hours a night for half the year. One of the reasons a regular EICR is a good idea, that would likely have been spotted before it actually failed like that. When I did a CU replacement for a house with that sort of big central storage heater, I specified an over size board, so the 50A rcbo for the big heater, could have a vacant space either side of it to aid cooling.

So glad you got it sorted, and a shame the first electrician turned out to be no good. At least you can carry on with the heating you have for the short term and have longer to plan a longer term replacement. Keep the details of today's electrician, now you have found one that knows what he is doing.

Bearing Boys have replied offering me this https://www.bearingboys.co.uk/Miniature-Bearings/6082Z-SKF-Shielded-Miniature-Ball-Bearing-8mm-x-22mm-x-7mm-131446-p They claim SKF are better than NSK I guess that has to be better than my unbranded ebay one?

Not much luck yet. Simply bearings and Bearing boys don't recognise 608Z1 I have found this that identifies my bearing but they look to be a wholesale supplier. https://en.tradebearings.com/608Z1_C3_E-817847.html And I don't trust Alibaba to supply a "genuine Japanese NSK bearing"

My cheap bearings arrived today and I have fitted one. I can now confirm the rear bearing on this motor is 8x22x7. I did not want to pull the old bearing off to measure the shaft size in case the bearing collapsed in so doing and I would have been left with the ASHP out of action until the replacement arrived, and measuring the shaft diameter when the end of the shaft is flush with the end of the bearing was less accurate, so I had ordered a 7mm and an 8mm bearing. The ASHP is now running with a quiet fan as before. Now I have the old bearing off, I can confirm It is an NSK 608Z1 All the writing on this rear bearing was on the side facing the motor armature so completely invisible until the bearing was off the shaft. Getting the old bearing off was not too difficult. I tried my smallest puller set, but that could not get into the limited space. I was mindful of the rotor being a permanent magnet and no doubt not very strong. Levering anything against that would no doubt end in a broken rotor. So I hunted around various tubs of odds and ends in the garage, and came up with the brass nut off a 28mm compression fitting, which passed over the bearing and rested on the steel core of the rotor not the magnet, and then a screwdriver under each side to gently ease the bearing off. I will now seek a better quality 8x22x7 608Z1 to have ready for when the cheap one fails.

I very much doubt they will pay less. A long time ago now, when I was looking for my first house, I saw a Victorian terrace house for sale. It was not in a village but just a row of houses out on their own, fronting right onto a busy road, no off road parking, the only parking was a public car park about 200 metres away. I looked up the details expecting it to be cheap because of the lack of parking and inconvenient location. My bubble was burst very quickly when I saw the silly money being asked, and presumably someone paid for it.

It's all about the misconception that we can transition to net zero / sustainability without any negative impact on our lifestyle. Starting with we can all swap to ev's and they are just as good as an ICE car. No in many ways they are not. We can all switch to heat pumps for heating. Well you can under the right circumstances with the right upgrades but that is not always easy or affordable. We can all switch to cycling. Well you can for short journeys but that won't help most with a 20 mile commute to work each day. Cue they want us all to live in 15 minute cities. You don't need a car parking space because you should not be thinking about owning your own car when you can have a bicycle and use public tranport. Yes I accept we have to reduce our use on fossil fuel etc, but what irks me is the LIE we can do it with no impact on our lifestyle. I would have a LOT more respect for the people planning this, if they were just honest and had a grown up conversation with is, that not only do we need to change how we do things, we need to change WHAT we do and that means travelling less and doing less, which for most of us means our lives will be a lot less fulfilling.

I hope nobody buys them. I would not.

FORGET the electric boiler. Direct heated HW tank (just a HW tank with 1 or 2 immersion heaters. Electric panel heaters on the walls where needed. No need for water and radiators. Keep it simple. Then put the "newly refurbished" flat on the market before the winter and the tenant finds his heating bills are 3 times what they were last winter.

Gravity HW usually has the tank right above the boiler, and when heating HW it is just convection that makes the water flow, and the pump only comes on ti circulate hot water for central heating. If the pump is coming on now, look at why might be an electrical or controls problem? The big disadvantage of this system is you can't control the temperature of the hot water other than by adjusting the boiler flow temperature, and you can't have heating on without hot water.

It won't need to support the load, that is what the big concrete lintel is doing. What is this bit? I am going to take a guess and it's a porch and steps at the front or back of the house, not the main structure of the house? Someone has made that gap for some reason, what is inside when you remove the loose bricks? is access needed for something?

What are you using to tell you that the off peak circuits are "on"

You have a canal on your doorstep, Would it not be easier to make a viewing platform to see that?