ᐅ External insulation using wood fiber boards installed over OSB panels

Created on: 16 Feb 2022 05:19
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Baupfusch0815
Hello everyone.
I need some advice.
We have renovated an old house.
We removed the entire upper floor and rebuilt it using a timber frame construction. Insulation wool was installed between the beams.
For the exterior, I wanted to have the insulation and plastering done by a professional company.
They wanted me to cover the outside of the timber frame with OSB boards first.
Now, they were supposed to insulate and plaster, but the person responsible from the company said he doesn’t understand why the OSB is there. He said he can’t attach wood fiber boards onto it.
We have now obtained a second opinion, and they said we should remove the OSB boards. The window sills and shutters are already installed.
I’m not sure if I can remove the boards, as they were nailed in.
So my question is:
Can I leave the OSB boards in place, and is it possible to apply insulation on top of them so that plastering can be done?

Unverkleidete Innenwand: Holzständerwerk mit Mineralwolle-Dämmung, OSB-Platte links.


Kran hebt Fensterelemente auf Baugerüst eines Wohnhauses; Arbeiter auf LKW-Plattform.
Tolentino17 Feb 2022 08:24
I get it. The company is now telling you that they can only glue the HoFa panels onto other HoFa panels, but not onto OSB? Find another company.
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Baupfusch0815
17 Feb 2022 08:31
Tolentino schrieb:

I get it. So the company is telling you they can only glue the wood fiberboards onto other wood fiberboards, but not onto OSB?
Get another company.

They want me to install wood fiberboards, and then they can apply plaster on that. But the thing is, they say wood fiberboards don’t adhere to OSB.
Tolentino17 Feb 2022 08:49
OK, as I said, I’m not an expert in timber construction.
Have you already obtained the wood fiber insulation boards? I’ve read again, and it seems that not all wood fiber insulation boards can simply be glued in place. However, it is possible to fix them using special screw anchors or stainless steel clips, even on OSB boards (at least with the StoTherm Wood system).
I wouldn’t install them yourself now. Doing so would void the warranty. Especially with insulation, the work needs to be very precise; otherwise, you risk thermal bridges and possibly channels for condensation or similar issues.