Garald

Was thinking more of the narrow staircase...

Back on topic: was the reference to the 1500s an allusion to the obvious defensive possibilities of this setup?

Aha! Will finish reading it first. I've heard Soviet apartments also had carpets on the walls sometimes (for sound insulation).

Exactly.

Glue sniffing is much more harmful, surely. Hemp is harmful mainly because it is smoked. If the insulation here were baked into pies, and consumed in moderation...

Is that still tongue-in-cheek? I imagine it's fixed in place already.

I'm missing some sort of choice cultural reference here. Well, the celulose-based layer of the insulation does contain hemp, though not necessarily that kind.

Here is the staircase we were discussing before. It got a couple of cm narrower. (There were about 5cm of air behind the panel - that helped, but wasn't quite enough, so we had to rob the staircase of a bit of width.)

Sure, but what makes more physical sense?

Oh, I did a bit of hiking along the coast around St Ives years ago - it's really quite nice. Would do again.

Having been convinced that wood stoves in urban areas are evil, I am now thinking of putting an inexpensive ethanol burner in one of the fireplaces in the main room (library) - not for routine usage, but in case of cold wave/power outage/broken heatpump/self-indulgence. Question: does it make more sense to put it in the decorative mantelpiece (which may have once been part of a working fireplace, but has no flue): or in the working fireplace in the other end (which I would then not even have to pay to have cleaned, presumably, though it wouldn't cost a fortune to do so): ? The locations are different: there's a kitchen on the other side of the wall where you can see the non-functional mantelpiece, whereas, as you can guess from the insulation, the working chimney is on an exterior wall.

It turns out one can get a bioethanol stove for much, much less (see, e.g., https://www.leroymerlin.fr/produits/chauffage-et-ventilation/poele-et-cheminee/cheminee-a-ethanol/poele-bio-ethanol-p.html). Perhaps that makes most sense, then? Can start a new thread.

Correct. My grandmother told it with more drama - she's no longer around to confirm the details (unsurprisingly given her birth year), so I would have to ask my mother for confirmation. Something about the burn victim managing to collect herself and handing over her children to her closest neighborhood friend, but nothing (or not enough) could be done for her, with medicine being what it was at the time and place. Right, but it wouldn't make sense to put it in a hearth, as opposed to the middle of the room, right? Or is it safer to put it in a hearth (even if it may be the least efficient choice)? Sure (note: I am also tight), that's both the option to have handy and the argument to convince the architect that one shouldn't base one's heat-loss computations on a -10 C outside temperature if one is in the Paris area. Thinking now in terms of what to have as a backup plan if the electricity system goes haywire (either in the neighborhood or at my place).

Isn't kerosene great for accidental self-immolation (besides stinking up the place)? I think a neighbor of my grandmother's died like that.

There's also wood pellet burners, but those are very pricey, and so not even remotely an option for occasional usage - besides being electricity-dependent.

We've already cut off the gas - someone from the gas company will come soon to take the meter.

Plus, the problem here is not "I destroy the planet", but rather "I poison my neighbors and myself", so, no neighbors, no problem, no? All right, so - what do I do with my nice working fireplaces? More importantly: - What do I do if the heat pump fails? Ok, Ok, electric heaters obtained somewhere at the last minute. But: - what do I do during an electricity failure in the dead of winter?

That's pretty shocking. Anything useful I might do with the fireplaces?

(Current state of the house renovation saga: I'm having the attic properly insulated. The heat loss calculation sheet is now giving 5.7kW as the total loss when it's -2C outside - of course that does not take into account some imperfections inherent to any renovation. At any rate, given that heat-pump will also be used for hot water, the choice is now between a 7kW Saunier-Duval (i.e. Vaillant) and a 8kW Saunier-Duval, with the architect and one of the installers leaning towards the latter option. (Of course one should not be too keen to overdimension, but perhaps it's no tragedy either: the heat pump has an inverter, so it should be reasonably efficient even when running well under capacity, no?) I'm being advised by nearly everybody to compute heat losses and radiator sizes for -2C. (I'm in the Paris area; consider it to be very much like London in terms of temperatures, at least during the winter.) Even allowing a safety margin, this leaves open the question of what to do on those rare occasions when temperature go well under -7C or -10C, say. The place has two working chimneys - they haven't been used in the last few years, but the previous estimates asked for estimates from a chimney-maintenance business at my request, and the verdict is that one of the chimneys - the one in the house's largest room, the ilbrary - would be cheap and easy to clean properly. Of course open chimneys are very inefficient and also interior air quality, so the question is really whether to buy a modern, high-performance wood stove to install inside the chimney. Now, I've read that a wood-stove is in general a terrible idea because of particle emissions. But what about using it only during cold waves, as a backup mechanism? (This was actually suggested by a German heat-pump book I got.) Or if the heat-pump ever breaks down? And how eco-friendly (or not-utterly-eco-murderous) are wood stoves now, really? If I read information such as: Emission de CO (en %) 0.12 Particules fines (en mg/Nm³, @13% O2) 23 - is that good, bad, terrible?

ISOLIN HPV (reflective insulation) + 45mm Biofib Trio + hygrovariable vapor barrier (Proclima) + 13mm fireproof plaster

PS. The contractor proposes to do this for 3250eur+taxes (whether it's cellulose or rock-wool). Does this sound like it's in the right general ball park? The house is about 12m long (on the inside).