Hi, I'm refurbishing a stone barn, and am looking at aerogel.

Does anyone have any experience applying it directly to stone walls, in particular the blanket rather than the boards. Then direct plaster/lime over that?

I'm keen on this finish as I'd prefer a more irregular finish, rather than flat boards.

I've seen some European company are applying aerogel render externally (with aerogel granules in the render mix), but I've not heard back from any of them.

Any shared experiences on this would be very helpful - it seems to be a revolutionary product?

He (she?) wanted *irregular*, def not what you get with flat boards (and got no answer at the time). As do I, and have plotted various ways over the years, so will be interested in this.

Aerogel renders are certainly marketed & used here in France, but I've not seen it in the UK.

The main disadvantage of aerogel is the excessively high price. In central London the value of the floor area saved may be higher than cost of the aerogel, but elsewhere I'd guess not.

Posted By: djhIs aerogel render cheaper in France? Or otherwise, why does it get used if the economics are unfavourable?

Just looked that up and it's said to be:
- €400 to €500 /m² (thickness unspecified, https://www.dsdrenov.com/ravalement-de-facade/enduit-isolant/prix-enduit-exterieur-isolant/)
- €350 to €400 /m² (thickness unspecified, https://renodit.fr/articles/laerogel-en-isolation-un-materiau-innovant-encore-peu-connu)
- €150 to €200 /m² for 3cm (https://renovactu.fr/aerogel-isolant-comment-revolutionne-t-il-lisolation-thermique.html)

In some circumstances - listed buildings, expensive locations (e.g. central Paris) the price would no doubt be worth it. Aerogel renders are also claimed to have a long life (>50 years), which may justify the greater cost for some.

Posted By: Mike1The main disadvantage of aerogel is the excessively high price. In central London the value of the floor area saved may be higher than cost of the aerogel, but elsewhere I'd guess not.

Bear in mind too the disproportionate insulant performance and how this relates to plaster coating thickness. It may be feasible to use cork or something cheaper within the plaster instead of aerogel, but you either end up with a very thick plaster layer (which takes a lot of coats to build up) to achieve the same u-value, or you accept a worse performance in a standard plaster thickness.

So not solely about floorspace lost, but also what's practical for a plasterer to physically slop onto the wall.

My guess on the uptake/cost difference in Europe is that there is already a bigger market and install industry for lime there, and the aerogel is just seen as a 'performance enhancing' additive.