ᐅ Additional Interior Insulation in a 1970s Prefabricated House

Hi,
we are planning to renovate a prefabricated house from the 1970s and improve the windows and insulation.

Since the exterior is fully clad with brick veneer, the insulation will be installed from the inside.

Wall structure:
- 30 mm hollow core board (to be replaced by 22 mm OSB)
- 60 mm insulation – aluminum laminated on the inside
- 30 mm air layer
- 10 mm exterior board
- 29 mm air layer + brick veneer

Our idea is whether to add extra insulation with absorber fleece (sheep wool) onto the new OSB boards, or to remove the old insulation entirely and replace it with 18 cm (7 inches) of new insulation.

Maybe someone can help us or has better suggestions. We would like to do everything ourselves.

Thanks in advance.

I will never understand why “the clumsy don’t become the majority”: Questioners stumble into a forum, post their question like it was ordered and not picked up, without looking left or right. Anyone trying to cross a street like that would get run over. How on earth did they manage to get to school – is that why all the parent taxis pull right up to the front door???

The skilled forum user looks around, learns from the behavior of others (and the community’s reactions) how to ask questions skillfully, and immediately discovers the dozens of threads that already cover “their” question.

There are plenty of prefabricated houses from the seventies here, recently more and more discussed from the perspective of a thermal insulation upgrade. And with that come “guides” on how to ask questions more effectively (and to elicit ANSWERS instead of FOLLOW-UP QUESTIONS).

Please tell us more about the manufacturer and model, for example, so the existing wall construction can be examined more closely and the structure narrowed down. And suddenly, more detailed answers become possible. If I

CiddyBecks schrieb:

Wall structure: / - 30 mm (1.2 inches) hollow core panel (to be replaced by 22 mm (0.9 inches) OSB) / - 60 mm (2.4 inches) insulation – aluminum foil faced on the inside / - 30 mm (1.2 inches) air gap / - 10 mm (0.4 inches) exterior panel / - 29 mm (1.1 inches) air gap + brick cladding

understand correctly, there is an unidentified 60 mm (2.4 inches) thick insulation, foil-faced on one side, installed between 90 mm (3.5 inches) thick studs – likely Isover or similar – where the foil facing apparently also serves as a vapor retarder. The remaining 30 mm (1.2 inches) of the stud bays are “empty.” A 10 mm (0.4 inches) “exterior panel” (somehow symbolically “waterproofed”?) is supposed to stiffen the frame as a single sheathing layer and directly border an air gap, onto which (fixed how?) a full brick veneer is applied.

CiddyBecks schrieb:

Our consideration is whether to add extra insulation with absorber fleece (sheep wool) on top of the new OSB panels or whether to remove the old insulation and replace it with 18 cm (7 inches) of new insulation.
Maybe someone can help us or has better ideas. We would like to do everything ourselves.

Doing the work yourself is commendable, but hopefully not the planning too – and as I already said, better help is possible here if questioners “cooperate” more. I see no reason to replace the hollow core panel; I would rather aim to improve the quality of the build-up. What I miss in the “concept” – as mentioned, more mature versions have already been discussed here several times, if not fully elaborated – is a plan for what to do with the existing insulation (reinstall in the roof, which wasn’t mentioned here?) and consideration of an installation layer. I also haven’t seen an explanation yet of how 18 cm (7 inches) of insulation is supposed to fit into a 9 cm (3.5 inches) cavity.

Sometimes it really feels as if the internet was only invented a few weeks ago, and that no one could possibly have any experience with it yet ;-(

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https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/

Yes, they still exist!
Those who at some point started engaging with the topic of building a house.

Unfortunately, we are not experts or prodigies who appeared out of nowhere.
We just want our children to grow up in a secure home during these challenging financial times, and if it’s possible to achieve that by doing some of the work ourselves, then we prefer hard work and limited funds over arrogant professional knowledge hidden behind a keyboard and mouse.

So if there are still people out there willing to help beginners with house renovation tips instead of driving them away with discouraging answers, I kindly ask for your comments and some assistance.

Thank you very much in advance.

I sincerely regret that you apparently did not understand anything from my post. Let me try again to explain it in simple terms:
1. Your question already had dozens of helpful answers before you even posted it here.
2. You can find these answers in many other threads on similar questions.
3. Thanks to categories and keywords, these answers are not hard to find.
4. We are happy to complement this rich range of answers by providing you with some additional ones personally.
5. For that, we need more information from you because we cannot read your mind.
6. We wouldn’t immediately call it "arrogance" if you want to "let us die stupid" by keeping the secret of 18cm (7 inches) of insulation between 9cm (3.5 inches) studs to yourself. However, it does make it harder for us to give you more precise guidance.

CiddyBecks schrieb:

We just want our children to grow up in a safe home during these financially challenging times

Then you should be open to the idea of planning installations before (or certainly not after!) you put on the new sheathing. Good luck!

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https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/