ProDave

Yes we have an 11 metre long ridge beam, too long to be self supporting over that length, but supported by the 2 walls either side of the stairwell, making the longest span between supports 5 metres. And exactly like the sketch above, that load is split either side of a doorway with a lintel. All specified by the SE. The SE also specified how it all fits together including some fancy metal straps to attach the rafters to the ridge beam and specifying what fixings to use.

This is Scotland, 45 degree is normal, and there are very many constructional reasons why 45 degrees is so much easier than anything else. Agree 2300 ceiling height is too low. "normal" 2400 at least.

Against popular current trends, we have a room thermostat in the 2 main downstairs rooms, so when you light the stove, if that room is not already up to temperature, it's thermostat will soon turn it off as the stove heats. We also have a conventional boiler time clock as a master control, if I am lighting the stove, I go and turn the heating off at that. Surely even the fans of pure WC operation must have some kind of master controls so your system is not running all the time in the shoulder seasons pumping water 1 degree warmer than the target temperature around the pipes?

They probably would not need planning or even a lawful development certificate for a "caravan" and that would be legal if the occupants at least used some of the services in the house. To legally qualify as a "caravan" it needs to be within certain size limits which does allow a building of about 100 square metres. And it needs to me moveable as a unit. It does NOT have to be on wheels. Lifting by crane onto a low loader would qualify. So the test would be is it build on a strong frame or would it collapse like a pack of cards if you tried lifting it. The "caravan" is exempt from building control but BC would be needed for any connection to a drainage system.

Need pictures of what you have, manifolds, pumps, valves etc

I am confused. your other posts about issues with the builder showed snippets of drawings showing how it was supposed to be done compared to pictures of how the builder did it. From that I assumed you had full drawings and the builder was not building to the drawings. Are you now saying a full set of detailed drawings does not exist? That would certainly put a different perspective on the issue?

On a copper pipe? How much iron is in your water?

What price would the kitchen supplier charge for the correct clour standard sized shelves (too big)? then cut them yourself or get a local joiner to cut them.

When I did mine, I literally added ALL the costs of buying the plot, legal fees, planning and design fees, build costs etc etc to get the total price I had paid. I was never asked to justify it, but I worked on the basis if questioned that was a verifiable amount and telling the truth. If you get a surveyors figure, then that may be more, or less, than what it actually cost you.

That was a temporary ramp to keep the cat happy. I later added a platform outside the flap, and then a step lower down. The cat loved it. and BCO at completion thought it was a nice touch and commented on it. Sadly I don't have a picture of it yet.

I struggle with the concept of this hybrid arrangement. The basic reason for wanting a hybrid appears to be you have small high temperature radiators and a heat pump can't heat the water hot enough for them. So you add a heat pump to a system with a boiler. I can see in the shoulder months you might be able to run it heat pump only and have lower temperature in the radiators that would work at a time of low heat demand, and add the boiler to the mix when it gets colder. I could see that working with a changeover either / or situation. But that scheme above with the heat pump pre heating the return to the boiler, assumes the return temperature is low enough for the heat pump to add any meaningful heat to it. Most boiler fuelled central heating I see the radiators are run too hot to touch, and I very much doubt the return temperature to the boiler is less than 50 degrees. I just can't see this working in a completely automated fashion to add anything of value to the customer. I doubt the heat pump will ever produce heat cheaper than the boiler. Why would a customer want something expensive and complicated that saves no or little money? It really sounds like a "box ticking" exercise to get more heat pumps in use, but in a way that is almost guaranteed to get them a bad reputation.

Re the big gable end glass wall. That is where you will probably need steels. But all can be avoided if you compromise a little. This is our "gable end glass" wall in our sun room. By breaking it down into 2 windows with a central support, that supports the ridge beam and it is all done in timber.

Cut roof does not mean steels. Ours used Kerto beams for the ridge, less bulky that Glulam for a given strength. That also shows the "gable end" type of dormer we used.

As per the other thread (broken blocks) it is time to have a chat with the builders, to build up under these piers that are there for a reason, and replace the broken blocks. It is a good job you are keeping an eye on them, though a shame they are not doing it right without you prompting them.

No, get those broken blocks swapped, while it is easy to do so.

What is the heat source? Boiler or heat pump? Is it new, or old? Has it ever worked properly? So flow and return from heat source go direct to manifold via that 2 port valve. So I can see without the manifold pump running, the system pump will push water through the UFH pipes. There is a TRV that appears to open / close to regulate UFH temperature. That pump would indeed appear to bypass the UFH loops. I think that is a thermostat top right grey box? What does that turn on and off? Who configured the manifold like that and why? The wiring suggests whoever did it may not be the best and may not know what he is doing?

I see one upstairs bedroom is proposed with a balcony overlooking the full height living room. I feel fairly certain that Scottish regs require all bedrooms to have a means of escape window, and I doubt that includes climbing off a balcony to a downstairs room. So you will probably have to re think that. A dormer or gable end as I did will solve that.

A bit confused on the floor plan. Which is your main entrance door? The stairs appear not to be in a normal entrance hall but down a corridor? Why is top floor seemingly only using half the available space? For that style of house, I recommend a gut roof construction hung from an end to end ridge beam. That gives you unhindered space in the roof space. Easy to make it a warm roof with air tight detail at ceiling level, meaning even any eaves space is warm and incorporated within the insulated air tight structure. If you need extra headroom e.g for a bathroom create a little gable end in the roof structure for that.

Being "offshore" i.e. not even on Orkney mainland, I would first research concrete deliveries. Everything for your build will not only have to get to Orkney mainland (choice of 3 large ferries) but will then have to get to the outer isle on the much smaller inter island ferries. Given the ferry schedules and some of them take a while I wonder how you would get bulk concrete there? I would want to know the answer to that before deciding to use ICF which needs a lot of concrete, vs say timber frame which would be much easier to get the component parts delivered. I think a LOT of you decisions will be guided by what can be delivered to your island at sensible cost, e.g. I remember @Stones saying his choice of treatment plant boiled down to the only one he could get delivered, and that was to Mainland Orkney.

BEFORE you depressurise it to fix the leak, you DO have the fill loop needed to re pressurise it afterwards?

My problem is both of those are plural terms, i.e you are talking of more than one person. Until someone tells me otherwise, all I can come up with for one person is "it"

Diagnosing it probably needs a good plumber / electrician. It looks to be be plumbed S plan, i.e. a single 2 port valve for each manifold and one for the hot water, and looks to be fired by a gas boiler, so no reason at all why it should not work with any combination of UFH and hot water all at the same time. You need to be methodical. e.g Start with just one UFH manifold on. Check the motorised valve feeding that opens and only that one. And check that only that manifold receives no hot water. Then do the same for the others, just one at a time. Once you have determined they all work one at a time, try 2 together, and again make sure only the motorised valves that feed those open, and only those receive hot water. It will take time because between each test you have to turn it all off and let everything cool down otherwise you can't be sure where the hot water is flowing and not. Write down your findings, it is easy to get confused if you don't.

That is almost exactly what we did except ours was not trench fill but normal foundations. I dug 3 test pits for the SE to evaluate the ground, each down to 2M. I left one open (but covered over) and monitored the water table which went anything from hole almost empty, to water almost level with the surface. At the time I was building people kept asking why I was not doing an insulated and the wet ground conditions was my answer. Even doing that I had an electric dirty water pump to keep the trenches dry, BC inspection one day, concrete pour next day.

Have you just moved into this house? Has it ever worked properly? From your pictures I see a couple of isolating valves turned off (shut) and a switch turned off. Why are those like that?

Which bit did you rotate to stop the first leak? The nut on the right with the white bit, or the lighter coloured middle bit?