OSB board instead of sparse panel under slanted roof cc 120 cm?

[mpa]

We are in the process of extending a house with a pitched roof with trusses at 120 cm centers. To minimize the build-down, can you attach 11 mm OSB boards under the trusses and then secure 6 mm gypsum boards under these, instead of using battens + gypsum boards?

 

[SBH]

No. Glespanel is not just for having something to screw into.
You never want to have any board directly against plastic.

 

[Anders243]

Well, sparse paneling is not just for having something to screw into. You never want a sheet directly against plastic

I'm a bit curious why you wouldn't want OSB + plastic + gypsum?

The only reason I can see is that all the holes made to attach things will puncture the plastic, but maybe I've missed something

 

[SBH]

it becomes moisture which later becomes mold.
but I've only torn down a few such ceilings. maybe once in a while you avoid moisture and mold

 

[mpa]

Thank you! We were considering having this directly against 13 cm of glass wool insulation, without any plastic or vapor barrier because the house is not fully heated year-round, and we were unsure if it would be strong enough – do you think it is, and could there be other problems if we did that?

 

[holmberg87]

I would use gles, it's only about 2cm you save by using OSB and renovation gypsum.
And I would still use plastic in the ceiling even if the house wasn't heated year-round.
Is it a sloped ceiling?

 

[SBH]

Thank you! We were considering having this directly against 13 cm of glass wool insulation, without any plastic or vapor barrier since the house is not fully heated year-round, and were unsure if it would be strong enough – do you think it would, and could there be other issues if we do it like that?

Yes. It could work. But I wouldn't have used gypsum.

 

[mpa]

What would you have used?

And holmberg87, it's a slanted roof, and the rest of the roof is not covered in plastic.

 

[SBH]

What would you have used?

And holmberg87, it's slanted roof, and the rest of the roof is not covered with plastic.

Wood. Works in many unheated houses. Excellent for cleaning. In case you happen to burn a little dust behind the propane fridge/freezer.

 

[holmberg87]

What would you have used?

And holmberg87, it's a sloped ceiling, and the rest of the ceiling is not covered in plastic.

I would have used furring strips and drywall or some wooden paneling
Ah okay, well if you haven't used plastic before, you shouldn't use it now either.

 

[Gabbe1]

If nothing else, it becomes much easier to run electrical wiring with glespanel compared to OSB.

 

[Gabbe1]

well. sparse paneling is not just to have something to screw into.
you never want a board directly against plastic

That's how many houses have been built, and it's a fairly new invention to install a service cavity with 45-70mm insulation between the wall panels and the plastic. The service cavities were introduced not because there were problems with moisture, but because houses became more airtight by avoiding holes in the plastic, for instance, during electrical installations.

Now, I am indeed talking about exterior walls, but the principle is the same for roofs.

 

[SBH]

Many houses have been built this way, it's quite a new invention to place an installation layer with 45-70mm insulation between the wall panels and the plastic. Installation layers were introduced not because there were moisture problems outside but because the houses became more airtight if you avoided making holes in the plastic for things like electrical wiring.

Now, I'm talking about exterior walls, but the principle is the same for roofs.

Yes, it works in walls. I can't explain the building physics. However, you get moisture problems in the roof if you screw panels directly onto the vapor barrier. But I only have 20 years of experience, so what do I know after having dismantled several moldy roofs?

 

[vectrex]

yes. it works in walls. I can't explain the building physics. however, you get moisture problems in the ceiling if you screw boards directly onto the vapor barrier. but I've only got 20 years of experience. so what do I know after demolishing several moldy ceilings

You are wrong. In an old house with insufficient insulation, there may certainly be problems (but you would get them even with a batten panel in that case). With a modern insulated ceiling, there are guaranteed to be no problems!

 

[SBH]

You are wrong. In an old house with inadequate insulation, it can certainly become a problem (but you would also encounter that with sparse paneling). In a modern insulated roof, there are certainly no problems!

what is a modern house to you?
got a job last week where the private individual had chosen to place directly on the plastic. mold all over the ceiling. can't remember if it was paroc, isover or t-täk fancy plastic