See the difference between regular and oil-tempered hardboard?

[Yrrol]

Bought masonite today, asked for oil-hardened, double-checked if it was oil-hardened. (they had some mislabeled shelves otherwise)

But at home, I feel worried as I find the material looks so light.

Can you tell the difference between treated and untreated?

 

[Per_2014]

Light beige, not oil-hardened
Brown, oil-hardened
My experience

 

[vem_jag]

On some it says "oli temp." on the back of the oil-hardened one, with very small text.

 

[Yrrol]

Checked another store and theirs was almost black.

Returned to the place of purchase and checked for stamps, which weren't there. Also questioned them.
It turned out they had also hesitated and talked to the factory, which insisted they were hardened.

The surface is hard and shiny, the board stiff.

But once home, I lifted the tarp and saw that the top board's sheets had warped overnight.
- shouldn't an oil-hardened board withstand a night with a tarp over it?

 

[ClasseClas]

A hardboard treated with oil can be used as a roof covering or for garage doors without additional treatment. Strongly doubt that you have received the right board. It should be able to be exposed to rain without any problems.

 

[öringen]

The top strip definitely does not look oil-hardened. Even on an unhardened sheet, one side is completely smooth and shiny.

 

[myrstack]

Smooth and flat on one side it should be, but oil-tempered is not immune to humidity and moves freely like regular masonite. Thus, you can't make assumptions just because it has warped.

However, it looks like your water splashes have wet the surface quite thoroughly, and it doesn't seem like oil-tempered should behave that way.

 

[Yrrol]

Okay. No, I will probably have to remove these. Was promised to get the money back.

Doesn't feel like this was a stable solution, unless I put 100 nails in each strip.
Probably faster to make a new roof based solely on 22mm boards.