I have looked around this forum regarding insulation on the inside of lecablock walls and have understood that this is not recommended.
I have built a "shed" that has a regular wooden frame in three walls, but one is in leca because it faces a greenhouse (which will not be heated). In the greenhouse, there will naturally be cultivation, but more with use as an outdoor room, i.e., it probably won’t be excessively humid there all the time.
I intend to keep the shed heated to at least above freezing, maybe up to 15 degrees, but probably +5 most of the time. I have understood that the lecablock wall will leak some heat and therefore want to insulate it from the inside (since the outer wall is already plastered and finished).
I think I’ve found all possible combinations for this risk project here on the forum, but not the following:
From the outside:
plaster
25 cm leca
5 cm polystyrene
(possibly plastic)
steel/wooden studs 45 mm (preferably with insulation)
OSB
gypsum
There are ready-made iso-leca which are leca-polystyrene-leca. This becomes similar, but not with leca on the inside (I don’t have the energy to build that up...)
I am thinking the following: (from the inside)
gypsum, OSB, steel studs (could also be wooden studs, as no moisture should be able to come in if you have plastic between the polystyrene and the studs) – it’s just like insulating a regular wooden stud wall... What can happen if moisture comes through the leca, it stays outside the polystyrene, and if it were to come through the polystyrene, it stops against the plastic... And putting the plastic 5 cm in on the above construction should correspond to a maximum of 1/3 into a wooden stud wall??
If there should be an air gap somewhere – where should it be then? And should the air gap be ventilated? If it is ventilated with indoor air, it will definitely condense against the lecablock wall...
Or is this really treading into deep water?
