Mike

But could easily find out by selecting the slightly smaller heat pump in the software and looking at the result?

The rafters of a 1930s house would have been designed to suit the lighter weight of clay tiles - that's what I'd choose.

Not a great situation, but given the choice between spending £5K on a misting system, of £5K on legal fees, I think the former would be the better option.

Not a lawyer, but unless there is anything in your deeds requiring you to maintain the boundary wall, then my understanding is that you have no obligation to fix it - although if it is in a dangerous condition and collapses, then you could be liable for damage or injury. And, unless there's anything in your deeds requiring you to have a boundary wall, you could just demolish it.

EPCs certainly have significant flaws, but At a guess, partly because people cap their heating use and live with lower temperatures due to affordability. It's interesting that the article is using the criticisms alongside the rumour that the Government is considering easing the requirements on renting lower EPC banded properties.

Under the new (2021) rules in France, if the EPC is inaccurate the buyer / renter can now sue the seller / landlord for damages - probably (according to the legal advice) for the cost of bringing the property up to the declared EPC standard + reimbursement of excess fuel bills + interest, though AFAIK there hasn't been a case yet. Of course the commissioner of the report can in turn can pursue the assessor. Unsurprisingly, you can't get an EPC for €30.

Primary energy = the amount of energy burnt at the power station. A lot of that energy is lost in waste heat at the station and in transmission losses, so a very different figure from the kWh measured on your meter.

Either leave them as they are - or take them up and relay them tight together, and find a length (or two) of matching old timber to make up the gap against the final wall.

Standard opening doors? I can see the visual appeal of pocket doors, but they do present clearing, servicing, repair and noise issues. I've got one in the room I'm staying in now and it doesn't close properly...

Zehner have good units, but the price quoted for them varies considerably depending who you buy them from - and, in particular, in which country they are based.

170mm. Yes. Allow for heavy doors with edge seals & beef up the stud that the frame fixes to - you'll probably need a double vertical stud (check what the stud manufacturer says about supporting heavy door sets).

The Komfovent DOMEKT R 500 V is an unusual choice. Counterflow heat exchangers are mostly chosen for domestic use, rather than rotary ones. I wonder why they've picked it? Komfovent do have a similar model on the Passivhaus component database, and the performance looks reasonable, if not class-leading.

A cut of 10db = a halving of noise, 5db = a useful reduction, 3db = just about noticeable. So to go from 40dB to 60dB the airborne noise level would be a quarter of what you'd otherwise hear - a very significant difference. If impact sound is an issue, then you'd ideally want two independent studs, though resilient bars are an option. This is the one I'll be building later this year; 2 x 70mm studs, 2 x 45mm hemp sound insulation, with 1 x plasterboard + 1 x GypsoLignum each side. I'm expecting a reduction around 65db, though as I'm using GypsoLignum I can't prove that.

Aerated concrete blocks are notorious for cracking, even if all the recommended precautions are taken. I'd choose a medium density block instead.

Sounds OK for a detached newbuild, but can't see it working on a tight urban site or a retrofit where there is no access to the outside. And, having seen a neighbour battle with builders for years before eventually having to pay another to fix the problem (it was to make additional space for his growing family - the kids had left home by the time it was fixed) I'd add internal drainage as a precaution anyway.

Fully intend to run cooling this year in 300mm loops. I was involved with a commercial development a few years back where overheating was a problem and suggested using the 300mm-spaced UFCH pipes for cooling. I don't have their calculations, but the consulting engineers concluded that 150mm spacing would be required for it to make a worthwhile difference. Of course that's a specific case, but I've opted from 150mm maximum spacing since then. It will be interesting to see how you find it @ 300mm.

Personally I put loops everywhere (for maximum flexibility), and at no more than 150mm centres (to allow for the possibility of using it for cooling in the future).

No - but I would run ducts so I could easily pull cable through if needed.

Unfortunately that's not uncommon. That's partly why there are various discussions here about what to specify for sound-resistant partitions & floors.

Another reason for choosing MVHR is that it may well increase the value and saleability of your properly. I've just received a set of Energy Performance Certificate simulations for my current French refurb (I wanted to make sure I wasn't just missing a band boundary - I'm not). However - leaving aside the (correct) argument that EPCs don't always match reality - without MVHR I'd have been in the middle of band D; with it I'll be in the middle of band C, with no easy upgrade to B. In France, at least, having a poor EPC (E, F or G) can knock tens of thousands off the property value, due to laws that will make them illegal to rent (G from 2025, F from 2028, E from 2034). F and G are already selling at a discount of between 10 and 20%, while A and B sell for a premium (article, in French).

Yes, for me Siga Rissan tape or Illbruck FM330 foam.

As mentioned in a previous thread, the simplest solution is to look at manufacturers technical literature - they have built and tested real-world examples for you to choose from. Also, note that airborne sound and impact noise need separate consideration - most of the focus goes on the former. And know that, because decibels are logarithmic, a cut of 10db = a halving of noise, 5db = a useful reduction, 3db = just about noticeable.

Yes - and acoustic caulk is essential, as are airtight pattress boxes, sealing of pipe penetrations, etc.

I'm planning to use GypsoLignum - on the spectrum between Fermacell and HD plasterboard - with some very interesting properties. It can support 40kg on a regular screw / 80kg with a plug and screw / 125kg with an expanding plasterboard fixing.

A practice that's undermining Germany's energy efficiency targets : Germany’s inefficient love affair with open windows And noisy, if you live anywhere urban.