Here is my problem: I have an old house - nearly 100 years old - that I need to insulate but I have a few problems and concerns I need to deal with. The walls are essentially stone and an old kind on solid cement block.
I've been looking into the insulation solutions available in my market and it is basically a matter of gluing thick boards of styrofoam-like material to the walls.
On the outwalls this is not feaseable as the house faces a road with no sidewalk, so I'd be encroaching onto the road. Inside, adding 5cm of insulation would make small rooms smaller to the point some would be, for all practical purposes, rendered into generous pantries.
Because I live in a somewhat rural area, mice and rodents are a concern, so adding materials they can chew through makes no sense. It would be like supplying an easy to move through medium to run the entire house. I have seen houses and buildings with this kind of insulation chewed into, the moment the smallest of pieces of the hard plaster gets cracked, which is very easy. The added fire hazard is a concern as well, I'll admit.
I've already seen cork insulation but the base color is always brown and does not deal well with being painted on.
What other options may I look into? I'm in southern Europe but in an area with harsh winters.
Not in the eu, so translate the material names as needed. Foam board insulation with a layer of plasterboard directly over the top seems to be your only option. If you are worried about durability just use a thicker plasterboard. Keeping the assembly under 5cm might be difficult if you want a useful r-value.
I've seen that material, I think.
Does it look essentially like a piece of drywall lined with styrofoam?
I understand that concern and I intend to improve the thermal efficiency of the house but not at the cost of turning bedrooms into pantries.
The house is really old and there are rooms under 10 square meters; a standard couples bed (140x200cm) will not fit there and even a single bed will make the room feel cramped.
You would buy the foam and drywall separately. You can either glue the entire thing together or glue the foam and use tapcons (concrete screws) to attach the drywall to the wall (screws go through the foam) if you want to do something without giving up space... hang a tapestry? lol
Go for the medieval look.