George

Oh yeah it'd need an engineer to design it. That's why I put the '+'

Sounds similar to what I've done. Why did you insulate at rafter level or is it an occupied loft?

The height of the wall will make a difference. If it doesn't go full height then the wall at first floor will need to be subdivided some other way to comply with Part A, else it'll need an engineered solution. These sorts of things (Inc the movement joint) are detailed design things which an engineer can help you with once the layout is sorted.

In short yes . The wall length of 12m is for a 'wall panel' which on your sketch is the 6.1m and 7m. This is because the internal wall provide a buttress support to the external wall.

For oil vs ashp generally... Cheaper because of solar pv, no big tank in the garden, no arranging for deliveries, no risk of fuel theft. For my old system specifically, no fumes and was horribly inefficient. Obviously a more modern system would be more efficient and not be fumey either...

My go to for thermal breaks is Farrat - although I've only ever used them for beam-column connections they do a base plate break: https://farrat.com/wp-content/uploads/2022/09/DS-STB-Farrat-TBF-22a.pdf Alternatively, you could also design the baseplate to be supported only by the bolts and make them M24s+. Then leave a gap on shims and surround the baseplate with insulation. But overall I doubt the thermal losses are significant enough to worry about.

Absolutely. But that's more like -2C (depending where you), plus there's fat built in at each stage, especially using the MSC approaches. There is a downside to oversizing as in the majority of normal mild conditions, efficiency could be impacted, eventually costing more than the back up fan heater would have... It does depend a little on how able you are to sacrifice comfort or convenience in response to extreme conditions. Even with small children I don't mind, but the elderly or those who just want the system to work with minimal interaction you could justify a bit more over-design.

Designing for a absolute worst case once in a 10 year event like -15C (where I live, anyway) is no way to design a heating system. Plug in a fan heater if it gets that cold. I've successfully renovated an 1880s detached cottage to work with a ASHP. Three winters and running costs are comparable to oil, very comfortable and has been fine in the -6 to -10C we got last year. Yes costs increase in the very cold but on average it is better than the oil system

When I found out hydrogen flames are invisible I figured piping it into homes might not be a good idea.

Fabric first, insulate insulate insulate. You probably have a significant advantage with big thick stone walls. I insulated miserly 9" brick walls with wood fibre boards to great effect. ASHP + log burner to provide a boost when temperatures drop significantly below zero and as a power cut back up.

No need for conventional wall ties. It might make sense for the timber and masonry to be tied together, for example using battens frame fixed to the masonry to level the wall for when the panels get installed.

Sounds more like the cabinet legs aren't fully extended down onto the floor. Can you take the kick board off and check the legs? Beam and block can have some bounce but it shouldn't be excessive. Even solid floors will vibrate under impact forces.

It depends what load each prop is carrying but probably not, the blocks especially would be vulnerable to a point load. Your builder should be able to make an assessment of the load, with the effect of the weight of any floors or the roof needs being considered. Note that Strongboys should be limited to 340kg (acrows are much stronger but due to the eccentric load on the acrow prop it is reduced a lot), which is around 150 bricks or so. Easily solved though, either remove a few blocks and prop off the ground or use thick timber sleepers to spread the load. Be cautious as a prop failure (at either end) would be Very Bad.

I'm guessing some sort of windpost but looks like an odd place for it. Usually they are set into the inner leaf blockwork. It's not obvious how it supports the masonry.

Short answer is anything is possible, but the costs go up as it becomes more complicated. Seems like a lot of alteration for no increase in floor area!

Chicken pen and lightweight coop would be a good use.

I've been hunting around for whether different types of PM2.5 pose more danger or not. PM2.5 is a physical description of size and doesn't describe the chemical effect of the particulate. I haven't found a good answer - it seems to be that the measuring equipment is pretty good at detecting PM2.5 but it is not very good at detecting what it is made out of. The indication is there are more chemically damaging types of PM2.5. But there isn't enough evidence to be conclusive. Intuitively, PM2.5 made of carbon is probably less harmful than PM2.5 made of VOCs, ammonium & sodium nitrate etc. Still doesn't mean a wood burner is a good choice for urban areas but the overall picture is potentially more nuanced.

Was that from the structural engineer? I'd not want to be underpinning an old timber frame. The dwarf walls are quite short and would not react well to being underpinned. The 'load bearing ground bearing slab' sounds like a raft foundation - a reasonable way to build it but perhaps over the top. So long as the geometry works, a normal strip or trench foundation can work against old buildings - just need precautions regarding not leaving it open for too long and possibly stepping it up to match existing footing depth immediately adjacent.

Sorry, yes, PM2.5 from wood smoke in particular. I imagine there are lots of nasty particulates that as a species we can release.

Do PM2.5 cause damage to the environment? They cause damage to human lungs but that's not quite the same as fly tipping.

If that's the measure then we are doing well, as pollution is falling and should continue to do so. I have changed my opinion though... I do see now that urban use of wood burners is not a good idea. An interim would be to completely ban open fires and insist all wood burners in an urban area get upgraded to EcoDesign 2022 and see how things go from there. Rural areas, ban open fires from new builds...? I think outright ban is not going to happen and becomes hypocritical considering the need to move away from fossil fuels and the widespread use of BBQs and NOx from fossil fuel boilers etc. I do still think other sources of pollutions (gas hobs, daytime vehicle exhausts, deodorants etc) are still more likely to actually be damaging lungs due to the more immediate and direct pathway from PM emitter to lung. but this is impossible to prove currently.

It's not irreverent - NOx is more dangerous than PM2.5 ***clicked submit too early*** from wood. Although that is just basing that on this DEFRA report https://uk-air.defra.gov.uk/assets/documents/reports/cat07/1511261124_AQPI_Summary_1990-2012_Issue_v1.1.pdf

12m - but that's just the scope of application for Part A rules. The outer leaf brickwork may need a movement joint to prevent cracking. I discussed a similar issue here:

D-rigs usually have extra protection for the operator. All things being equal, bigger is better as it allows you to do more remotely and keep people out of harms way.

This is why I prefer mechanical connections like joist hangers. Any way of getting a small angle/cleat attachment to connect the joists to the beam?