Adding insulation to an old house.

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.

jocanib,

Cork insulation would usually be skimmed over with plaster. You could have a look at insulatiing plaster too, but I think that needs to be thicker than cork to work well. Less munchable by critters though.

In an old building, you need to use breathable insulation, breathable plaster, and breathable paint (and breathable mortar, if you’re repointing the outside). The moisture needs an escape route.

Thrashy, (edited )
@Thrashy@lemmy.world avatar

With old masonry wall construction, you need to be very careful about how you retrofit insulation to the walls. Insulating the interior makes it very likely that you’ll have moisture-related degradation of the stone and grout making up the wall, as you’re cutting off drying potential from the interior side of the wall. If it’s possible, insulating the exterior is your best option, otherwise you’ll need to be very conscious about selecting vapor-open insulation and finishes on the interior side, which will limit your options considerably. This article from Building Science Corporation goes over some of the details, and offers some options for interior-side retrofits that might not cause the wall to fail down the road.

archomrade,

It is very common in the US to use foam boards with z furring channels to insulate agaist concrete or similar materials, but using furring channels with just about any type of insulation would work (foam is the most efficient, though). You can then fasten drywall or your typical wall covering to the channels and paint as normal.

Just about any solution will reduce your occupiable space though, or protrude on the exterior. Most jurisdictions in my area are ok with encroaching a few centimeters for the purpose of higher energy efficiency, but I have no idea about your situation.

rhythmisaprancer,
rhythmisaprancer avatar

Can you inquire with your local leadership about encroaching into the roadway? It really does seem like this would be your best option. Or reconstruction.

qyron,

None is an option.

czardestructo,
@czardestructo@lemmy.world avatar

Perhaps not the same but I own a 150 year old home in America and I had foam insulation blown in. The insulation it provided was minor but what it helped tremendously with was drafts and air exchange. On older homes air leaks and sealing any cracks and drafts can potentially save you more money than adding actual insulation depending on how leaky it is. Food for thought though it might not help you.

qyron,

That was the kind of thought I was looking for.

robotopera,

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.

qyron,

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.

robotopera,

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

qyron,

Go for the medieval look.

towerful,

You could put lining paper over the cork, so you have a paintable surface.
My flat has plaster render over brick for internal walls (external walls are lath & plaster).
My hallway has a styrofoam backed wallpaper. It gets damaged SO easily, and I haven’t found a decent way to repair it. I presume at some point, I just need to repaper it.
I think cork is a bit hardier than styrofoam, but just a heads up for high traffic areas

qyron,

The cork I’ve been able to find specifically warns against painting it or covering it in any fashion. I could go for an accent wall on it but it is not a material easy to match and the texture is just off.

I may use cork liner on the floor before setting down wood pavement (I intend to reuse every piece of wood I can manage to salvage) but not on the walls.

And yes, styrofoam is horrendously fragile. At some point you may have to consider replacing parts of it, which apparently is very easy, but just putting up such a fragile material doesn’t make sense for me.

Thavron,
@Thavron@lemmy.ca avatar

It might be helpful to know what kind of walls you have. What is the material, do they have space that can be filled with insulation material?

qyron,

Stone. No gaps I can take advantage of.

pdavis,
@pdavis@lemmy.world avatar

I don’t really know of a way that you can add insulation without taking up interior space, exterior space, or replacing the wall with more modern materials.

  • What about the sides of the home not facing the street? Can you add an exterior layer of insulation and then new exterior siding to those walls?
  • On the side facing the street, you could replace the stone wall with a different type of wall that was more thermally resistant. This would of course be a major undertaking.
  • I am sure you have considered fully insulating the floor and ceiling as best you can.
  • If rodents and or insects are a concern, look into Mineral Wool/Rockwool Insulation.
qyron,

Taking some available space away is a given.

Many places have a long experience in dealing with cold, which my country lacks, hence I’m asking here for advice. The default solution was either endure it or burn more wood.

I may be able to shave off one or two centimeters of the total volume required as the walls are currently covered with a very thick layer of cement that was set with no concern to prior levelling the stone (in places where the mortars started to fail I chipped away to clear the loose material and there are spots where 2 to 3cm of cement could be saved just by grinding away an edge of a stone) but going by the solutions my market has available, I risk needing to layer up to 10cm of material on my walls.

I do intend to insulate floor and ceillings as they will be, for all practical purposes, rebuilt, as the current wood floors are thin.

The house is squeezed between a pedestrian street, where I can’t encroach, as there is little room already, and another house. I do have one wall I intend to insulate from the outside as it faces an empty plot.

Mineral wool I have been looking into it but I was warned it wicks moisture. Is this true?

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