OSB, wax or not?

[UV5]

Planning to build interior walls with insulation in a cold garage. Possibly a future warm garage. Will unwaxed OSB absorb moisture? Also planning to paint white. I have painted on waxed OSB indoors, didn't go well. Some retailers don't even specify if the boards are waxed.

 

[MathiasS]

I have had regular OSB on the walls in a storage room that is not heated for many years now, see no problems with the boards.

OSB is excellent as a reinforcing board but you should of course have gypsum as the surface layer.

 

[UV5]

Why plaster?
I just want white bright walls.

 

[fribygg]

Fire protection

 

[Johan Gunverth]

Going to build interior walls with insulation in a cold garage. Possibly a future heated garage.
Will unwaxed OSB absorb moisture?
Also planning to paint white. Have painted on waxed OSB indoors, did not go well.
Some retailers don't even specify if the boards are waxed.

OSB always has wax in it. It's part of the manufacturing process. It has nothing to do with whether the surface is waxed or not. About 5% of the board is non-wood material. If I remember correctly, it's about 1% wax.
Whether the paint adheres or not depends largely on whether it can form a layer that both grips in the pores and holds itself together. Rolled latex might work. Linseed oil paint probably won't work well at all, and ocher paint will wash away with the first rain (I've tested this myself).
Why not use fiber cement directly, so you get a durable surface that withstands fire, is moisture-resistant, and can be painted?

 

[Cheesen]

Fire protection

It is basically the same fire rating for OSB and gypsum. The burn-through time is nearly the same.

 

[Boxer63]

That contradicts everything I've heard about plaster and how a firewall is constructed. Do you possibly have a source or something else you can show to prove your claim?

 

[fribygg]

It is basically the same fire rating on OSB and drywall. The burning-through time is nearly the same.

Is träguiden.se wrong when they write that drywall is in class B and wood-based boards are in class D?

 

[MathiasS]

Why plaster?
I just want white, bright walls.

Because painted osb is ugly.

 

[fribygg]

I just want white bright walls.

Wouldn't it be suitable to put up white bright panels then?
I would think that Cembrit has a suitable product if you don't want plasterboard.

 

[Cheesen]

Is träguiden.se wrong when they state that gypsum is in class B and wood-based panels are in class D?

Fire classification is based on the time it takes for burn-through and it is almost the same time

 

[fribygg]

Fire rating is based on the time it takes for burn-through and it is roughly the same time

But the fire rating is better on drywall