Execution of wooden beam ceiling, help needed

Hello everyone,

we had a wooden beam ceiling installed in our garage for the use of the upper floor (gable roof garage). According to the offer, the creation of a wooden beam ceiling is included in the price. Now the carpenter confronted me with additional costs of 1,000 EUR for the installation of OSB boards on the upper side of the ceiling. I am a bit puzzled because I assumed that the top finish, i.e., the walkable surface, was already included with the offered wooden ceiling. Especially since I emphasized at the time of order placement that the area should be used as storage space and designed for a corresponding load of 250 kg/sqm. I am quite at a loss because, in my opinion, the top finish is already included by definition in a wooden beam ceiling.

Can someone help me here? Thanks.

Yes, you are basically right. What annoys me is that the expert know-how of the carpenter was knowingly used to my disadvantage. And nevertheless, additional costs arise for me.... What thickness should the OSB panels have in order to be walkable and also load-bearing? Is 18mm sufficient?

Hello,

What thickness should the OSB boards have so that they are walkable and also load-bearing? Is 18mm enough?

If you want to store things up there, I would rather go for 22 mm; comparable chipboards are also sufficient

Rhenish greetings