George

I did put the order in, plus an extra 2.4kW of solar (if the DNO says yes). Won't get installed until March but in time for the price cap to end. Fully aware prices could drop back to 'normal'. But a non-financial benefit is I should be close to being energy neutral, even if I still rely on the grid.

Remove it completely if you don't want it. No point suspending a few tonnes of bricks and keeping a hole in the roof. If you do want to keep the bricks, then unfortunately gallows brackets are unlikely to be viable. But get a structural engineer involved. Building Control used to be a bit more forthcoming with advice but after a few disasters then tend to ask for structural engineer's design (and insurance).

My experience with a large twin fan unit is that they're not very loud and in general terms noise dissipates quickly. The time they are on most, in the winter, is the time you are outside least. In summer it is only for hot water and has highest COP.

Edit - somehow deleted the numbers bit. I've always calculated oil and ashp to be cost neutral on running costs. Fuel oil was up to 150p last year. It came down to a pound and is around 88p on the local buying group. It really depends on boiler efficiency but both come in at around 10p/kWh delivered. I've also got solar so actual cost is lower, but that can be ignored. I think ultimately, all the technologies work OK with similar-ish running costs. There's an expectation placed onto 'green' technologies that they have to be more cost effective than oil and gas. But really, we should be starting from a position of should we be digging up fossilised carbon and setting fire to it if we don't have to? Part of the payback for me is I'll be able to look my children in the eye and said that when I had an investment decision, I went for the most sustainable option available at the time.

What's the payback time of a gas boiler?

It does except why use marginal rate? Electricity consumption has been falling for many years, and quite dramatically per capita. ASHPs and electric cars will likely reverse this trend but due to the cheapness of renewables, you'd expect this to be largely renewable sources to take up the increase. Or at least, not reduce their contribution from today.

The counter argument for a heat pump is that it uses gas more efficiently than just burning it in a gas boiler. 1kWh gas into a CCGT results in 0.6kWh electricity. At a SCOP of 3, you net 1.8kWh heat delivered. (Ignoring significant losses and assuming a 100% gas powered grid) I have wondered whether gas powered heat pumps would be a better medium term solution. They exist as you can get gas powered fridges. I wholeheartedly agree electric cars are not good for the environment. But I think overall they are marginally better than petrol/diesel. Bicycles are the proper eco friendly choice. Edit - I've just remembered there is a government research paper from years ago that included gas powered heat pumps. Because the electricity grid has a significant (and always growing) non-carbon input they were worse on a carbon intensity measure than electric heat pumps. This was a carbon focused research rather than price.

Bookcases around the edge of a room wouldn't concern me, particularly - certainly not if the joists are perpendicular. Bookcases placed in the centre of a room I'd like to know about. It's unlikely to have a strength failure (due to slight overdesign, load sharing and safety factors), but could certainly affect serviceability (deflection), especially with timber as load duration is a factor.

I live in a solid wall house built in the 1880s. The ashp costs less than I used to spend on oil (although its a thermally much improved house and the old oil system was incredibly inefficient so it's a moot point). Can't hear the ashp at all from inside and when outside when immediately adjacent to it as I said, it's a noise, but it isn't noisy.

Oil won't work without electricity for the pumps etc so that's a draw in my book. Also - electricity supply will always be a priority. At no point for the rest of humanity's future will we not be generating electricity somehow. Fuel oil, however, will hopefully get phased out in the new few decades! I could see a carbon tax being implemented at some point in the next 20 years, and at a minimum the green levies moving from electricity onto gas/oil. For a truly secure back up plan, have a biomass option (I kept my log burners in the house when I renovated). I don't understand the marginal vs the average rationale. Oil con - big ole ugly oil tank in the garden. An ASHP is a fraction of the size (although it does make a noise - not noisy - but a noise).

Could you post some pictures? hard to visualise. If there's a useful backspan for a cantilever, that's always preferable to trying to get an attachment to the a wall (pure cantilevers are very difficult to make work on masonry). Otherwise putting a post in is a safe bet.

Architect should have drawn an appropriate method using normal masonry else specced a product. You can't do what the builder has attempted because it's rubbish- but at least it was as a trial run!

I'd be aiming for a 50mm cavity, so two layers of 25x50mm battens. If battens are spanning, then minimum size is 25x50mm up to 600mm span to reduce risk of falling through them (25x38mm can be used up to 450mm span). 19x38mm generally aren't used except for repair to old roofs.

If you don't need permission to build it, don't put it on the planning permission. (Although sneaking on one liners about caravans and shipping containers for temporary storage can be useful)

Rafts can typically be only 450mm deep which would usually mean you aren't digging down below a foundation and need to do a party wall agreement. However.... a PWA being objected to doesn't mean you can't do the work. They'd have to get a surveyor for themselves and that surveyor could only point out real issues or just say it's OK. They can't just instruct the surveyor to object for the sake of it, at the risk of their professional membership(s).

A structural engineer is someone who is a Chartered Engineer (CEng) and a member of either the Institution of Civil Engineers (MICE) or of the Institution of Structural Engineers (MIStructE). Their post nominal would be CEng MICE or CEng MIStructE. Is this to check the house generally or just for the design of the crack stitching bars?

It's just short lengths of B10 (10mm diameter) bar. usually you overlap by 400mm, so a 800mm length of B10 to lap 400mm onto each sheet. I think it would be more fiddly than lapping sheets, but all reinforcement work is fiddly! I have to say, speaking as a structural engineer, 3No layers of A393 in the top of a slab seems excessive. I didn't put that much into industrial warehouse slabs. Is it on piles/vibro-stone columns or particularly poor ground?

We got a combination microwave when we lived in the static caravan (didn't much like the gas cooker that was installed). A combination microwave has a grill and a fan (which blows air over the heating element to replicate an oven). As far as I can tell, that is essentially what an air fryer does - blow air over a heating element. Add in the magnetron and a combination microwave is an incredibly versatile cooker. So... yeah, my recommendation is get a combination microwave!

Sell it and get the buyer to take it down. Shed prices are crazy at the moment and even a timber one would probably get some interest.

Don't know it if helps, but my average year usage is 3530kWh just for the heat pump. At 28p/kWh that's £988.40. This compares favourably to oil boiler alternative (no mains gas). We have a mix of radiators and ufh, but mainly rads. Water demand is approx 15% of heating demand - believe this was based on occupation and bathroom assumptions. The use is actually considerably lower than the design assumptions - about half. I think this is because it's an old house so conservative assumptions were appropriate, the wood fibre insulation is performing better than the u-value would suggest and the ASHP is in effectively a wind tunnel between the house and a barn. House floor area is 176m^2, but I can't give a heat demand because a proportion of that 3530kWh is for hot water, heating is helped with occasional log burner use, solar gain and SCOP of the heat pump not accounted for!

Just on this - I looked at the Eddi device but it says it can't hook up to a heat pump controlled immersion. Or do you have a twin immersion tank?

Is it adjacent to a flue? And is the flue in use and/or lined? The crack hasn't significantly opened up but I'd certainly monitor it. Repairs would be to reinforce the timber and repoint.

You can justify either a) or b), but I'd select whichever gives the deepest formation (underside of foundation) level.

I'd missed this thread before now. Structural engineer questions... Are you going for a load bearing straw bale wall or a timber frame with a straw bale infill? Are you doing a stonework plinth with a suspended floor? Have you done a ground investigation? On site clay plaster may be an option and while it is labour intensive, it does cut down massively on import (useful if you need to shift a bit of mud from landscaping) Are you doing drained rubble fill foundations or some sort of raft? As I'm a part time farmer and structural engineer I've always been very interested by straw bales. We still make a few little bales but nowhere near as many as we used to. While I've done a few concepts proposals for straw bale homes they've never made it to construction.

Solar panels paid for themselves years ago. It's all FIT + reduced electricity costs, at least until the inverter goes pop.