ᐅ OSB panels in the pitched roof

Created on: 12 Aug 2017 22:47

We want to insulate the entire roof with 20 cm (8 inches) of mineral wool.

We plan to build the attic floor using OSB boards.

While reading and researching online, I have come across several points that made me think more carefully...

Is there a risk of mold forming beneath the OSB boards?

My understanding is that if the insulation between the rafters is properly sealed with a vapor retarder, the attic floor project should not be a problem.

We are also considering insulating the ceiling (the upper floor ceiling under the roof).

Does that make sense?

Joedreck14 Aug 2017 14:16

#13

Yes, Karsten, that is correct. If there are any defects in the vapor barrier, moisture that gets in can escape upwards through the gaps in the spruce boards. OSB is too dense for that.

truce14 Aug 2017 20:41

#14

We have installed ESB boards. Unlike OSB boards, these are vapor-permeable—similar to tongue and groove boards but easier and faster to install. They also look great.

Dachboden mit schräger Holzdecke, Stützpfosten, Holzfußboden und kleinem Fenster am Rand.

ooooA813 Sep 2017 23:02

#15

Hello,

what about an insulated reinforced concrete ceiling?
Can I lay the OSB panels without gaps here, or is there also a risk of mold problems?

Attic: stack of OSB panels and wooden battens; a ladder with work gloves leaning beside it.

Joedreck14 Sep 2017 04:23

#16

Is the ceiling new? Reinforced concrete is generally not vapor-permeable. So basically, it is possible. However, if the attic is not heated, you definitely need additional insulation!

ooooA814 Sep 2017 07:17

#17

Hello,

the attic is an unheated roof space, so it will not be heated. As you can see at the hatch opening, there is about 25cm (10 inches) of insulation on the concrete ceiling. Did you mean this insulation?

Joedreck14 Sep 2017 08:57

#18

Yes, exactly. In my opinion, there is no objection to that. The concrete ceiling already functions as a vapor barrier.

ᐅ OSB panels in the pitched roof

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