Using oil-based paint is essential. Just painting the OSB like you would paint plywood will leave the OSB rougher and the paint will bleed through regular primer, while using water-based paint causes the OSB to peel over time, making it look unattractive and requiring regular maintenance.

Do you have to paint OSB board?

These boards can be painted, but this will cause some issues. First, it will not have a smooth texture, no matter how hard you sand it. You may also need to use more than two coats since the open strands will quickly absorb paint. OSB board also gets damaged easily in places with a lot of moisture.

Does paint protect OSB?

A good exterior paint can actually add to your OSB's water resistance, as well as add a splash of color to your project. If you intend to paint your final project at all, make sure it is added before any waterproofing so the sealer can also protect your top coat. ... Then, brush your paint on the surface of your pieces.