Which material is suitable for storage flooring on a wooden beam ceiling?

Hello everyone,

we will soon be installing our wooden beam ceiling for the attic. With which material would you finish the attic floor? It should be walkable to store a few boxes and decorations. That's why I am looking for an affordable solution. So far, only OSB or tongue and groove boards have come to mind.
Do you have any other ideas?

Thanks to you :)

Generally, tongue and groove boards are recommended because they are vapor-permeable. It's just a bit more labor-intensive to install than OSB. With OSB, I would leave gaps at the edges for ventilation underneath. In theory, dry screed boards or something similar might also be possible, but it won't be cheaper... You could at most browse (e**y) classified ads for old floorboards from demolition and renovation....

Do you have any other ideas?

These are probably the two more sensible options. I would choose the one I prefer to install. For me, that would be rough-sawn timber, because it's more manageable and you can throw leftovers into the stove or always find other uses for them in/around the house.