JFDIY

If you must have them, buy one, then assuming it's a regular O-ring measure the cross section then buy it off the roll and using super glue it's easy to make your own

Someone's cast-off shower made its way above my garage sink, does the job.

And I thought I was one for over-thinking a job...... you better get that holiday booked. ?

A bit of tweaking of the position here and there should get it mostly right. i.e move the whole footprint up and rotate it clockwise slightly. At least it's off towards the stronger side where you have more walls forming buttresses to the foundation. Not worth worrying about really I'd say, at least all the walls will be on the foundation! - I've heard of people having to build right on the edge due to incorrect set-out.

I made a hoist using a ladder and winch, was a god-send. As I could load the scaffolding then set up on the roof pitch and send up 60 tiles (plain clay) at a time and use what I could, then send back down the mega twisted ones and re-load again. Tiles were reclaimed , well over a hundred years old and every one was a different shape needing selective placement. Anyway the hoist i put together was similar to this; https://youtu.be/u3qNB8GDOzY

If you've worked in precision engineering (as I do), then unless you get a very good builder then book a long holiday and come back once it's done, you will be mostly disappointed otherwise. I've ended up re-visiting so much of our place, getting there now though, and I've learnt not to expect (total) perfection.

I've been tempted to do that on mine, but I might try disabling the switched boost (from bathroom) and let it run on humidity control as I tend to have a shower last thing at night, usually a few hours after my better half has gone to bed, and boost when you're trying to sleep can niggle you a little bit .

Here's mine, door set 50mm low into outside skin to give level threshold. FFL is top of hardwood cill/ top of DPM under sole plate. Inner skin stops at sub floor level and DPM into reveal. Mine might not be normal (no cavity) and with benefit of hindsight I would have left the inner skin out and poured the floor into the reveal, just incase floor slab/footing move and create a stress point, but the insulation should accommodate it.

Mine were all short to span drainage runs in a dwarf wall. What span are your openings? You could contact a lintel manufacturer and see what they make that could be suitable. Longest lintel off the shelf I can see is 1200mm which would do 1000mm span at the most, but there's sure to be options. Even using a steel one and cutting the flange down might work. What are you finishing the wall with, could you loose the excess of a deeper lintel? Edit to add: have a look at stressline or someone similar, they're showing a 2100mm lintel (65mm section), which could do up to 1800mm opening depending on loadings. I'm sure they can do longer on request

Standard concrete lintels are approx 65mm X 100mm in section, depending on span. As far as I know they are pre-stressed with no specific orientation. The steel is central, can you just use it in its side and cut the blocks above in height to accommodate it? You can also get 70mm concrete blocks, got a pack here in the midlands that are left over from my build....

You end up with about 1/4" either side if you're careful.

Unlikely to be a problem, it'll dispurse if the wind is that strong. Got to be worth a try.

Can you swap the inlet and outlet pipes to atmosphere easily to see if that is better?

I would also make sure the master tap has the outgoing pipe looped up and over the height of the outside tap, and supply the tap from above, so if you isolate it in winter you can drain the water easily to prevent freezing. Mine is fed from beneath and you can not drain it easily

What work needs to be done to the roof to bring it up to regs? Looks like there is no membrane under the lower part one side. If there is a few bits to rectify you may find that new raised collar trusses would not be that expensive. You could do just the half over the kitchen/dining area. Or go for fully vaulted in that area and raised collar trusses in the bedroom. I think without doing something you take away the appeal of a barn; most people will expect a bit of a feature and spending a few £k here will make all the difference. I take it there is no option to lower the floors?

Does it need to be a brick structure - is the current building skewing your vision. You can get some decent timber cabins that you could insulate and make dry, a brick or block building will have thick walls and need heating in winter to stave off the damp feeling unless it is well insulated. A timber cabin kit would only need a base forming and be a quick project.

It's all do-able, depends on how much you want to take on. Main thing you'll need is a decent laser level and receiver to save time getting everything level. Straight timbers and stakes work fine for forming the edges, as will hired steel forms. Benefit of timber is you can do it at your own pace and not be on the hook for weekly costs. If you use a mix on site concrete firm you can dictate the pace and you only pay for what you actually use.

I wanted to use wunda (based on good reviews here). But upstairs I need to use a fully flexible pipe to feed through metal web joists without over battening to save floor height. We just could not get to an agreed proposal, so in the end I went with TUS in Burton upon Trent, they knew what I was trying to achieve, sent floor plans quickly and changed the order several times to meet my requests, all while working from home due to the recent worldwide meltdown. I haven't fitted any of it yet, but it looks good quality (it's branded emmeti, grundfoss pump) and it was on my drive 9am the day after placing the order. I got them to leave off the actuators as I will get the salus auto balancing ones from wunda.

CVC

Bird in the hand is worth two in the bush. I have a feeling everyone will be short of stuff soon and you might be waiting then.

I fitted an 80kg skylight in a second floor roof on my own, it all comes down to planning and using mechanical advantage. I made a sled from an 8x4 sheet of ply with a couple of battons on the back, and nailed some more battons to the roof to stop it going sideways then hoisted it up using a simple pull winch. As mentioned above, by @BotusBuild a few planks to make a ramp up the stairs and drag it up.

Hi and welcome. Depends if you can really use the space it creates? - will it add to the room or detract?. If its brickwork finish, you might make that corner awkward/expensive if you have to get bricks cut and bonded. I've seen roofs where they would just put a facia on that, easier with plain tiles as you can raise that edge to encourage water to stay on the roof, might be a bit of a pain on large format interlocking to do. you could 'hip' the last part and incorporate the change in angle and maintain a gutter.

Just to add to your dilemmas, if you throttle the airflow at the room terminal you will find that as you close them down (on rooms closest to the unit) the noise increases. Its been said that if you throttle the flow at the manifold the noise created is less noticeable. Some suppliers sell knock out restrictors for this purpose.

Wouldn't it have been prudent to find the land owner of the tree before you designed something you can't build? You quote in your first post that you 'work in planning', so should we consider that to be a professional- that should have known the ropes? Put the apprentice on a digger, make it a big one and swing the wrong way when taking the footings out, might cost a few fence panels as well, but you've got to make it look convincing. Otherwise re-design or offer them some cash.

Why the complient seller? It has permission for domestic, so there's no risk, if you don't get permission, you either apply for a complete re-build (there's been a few around my way like this), or do the conversion and then apply for a large out building Little risk if you ask me.