ᐅ External insulation for a historic building built in 1908

Hello everyone,

I have just purchased an old building from 1908 and now plan to carry out a full renovation.

The interior work is mostly clear to me – I will also discover many things once the building is stripped down.

My question is: the house has solid 60cm (24 inches) exterior walls, as was common back then. Is external thermal insulation useful with this wall thickness, or is it rather ineffective?

I look forward to your suggestions.

Best regards, Jürgen

I am not a big fan of insulating old buildings because the drying process often no longer works afterwards. Consult a true expert to avoid paying for lower energy costs with mold issues and indoor air quality problems.

hampshire schrieb:
I am not a big fan of insulating old buildings because the drying process often no longer works afterwards. Consult a true expert so that you don’t pay for lower energy costs with mold and indoor health issues.

Thank you for the quick reply – that was also my thought, that there could be problems with moisture control!

Lemberger schrieb:
the house has 60cm (24 inches) solid exterior walls (as was common in the past)

For 1908, I would definitely not describe that as common.

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Between 1880 and 1915, houses were built very solidly. Money was abundant, the French paid very high repair costs, and the industry was booming. This allowed for more massive construction. The building fabric is often excellent, though the installations are, of course, outdated. By the way, old Bakelite switches can be worth a small fortune. Don’t throw them away!

Lemberger schrieb:
60cm (24 inches) solid exterior walls (as was common in the past) – is adding external insulation worthwhile with this wall thickness, or is it rather ineffective?

With a wall thickness of 60 cm (24 inches), I wouldn’t consider adding another 10–16 cm (4–6 inches) of insulation unless you like the bunker look.

What kind of building is it? A "villa," an old church, or a historic craftsman’s house?

Some neighbors on our street bought a "villa" from that era. The wall thickness is about 50 cm (20 inches). When they replaced the windows and inspected the masonry, they found a cavity wall made of 24 cm (9.5 inches) solid bricks, a 13 cm (5 inch) air gap, and an 11.5 cm (4.5 inch) outer leaf (plastered). They had the cavity professionally filled with blown-in insulation, fitted triple-glazed windows, and properly insulated the roof. Their energy consumption is comparable to a modern new build.

Many buildings from around the turn of the century have cavity walls (sometimes plastered). It’s best to check your walls as well – 60 cm (24 inches) thickness rarely means solid masonry without an air gap.