Carpet tiles- Can I paint/stain the particle board sub floor?

If any thing spills on the particle board it will mold and smell. Ply wood is stronger over the particle board, it might hold carpet tiles

Particle board doesn't have a smooth solid surface, since it is made of wood particles and resin, it is always shedding particles and the surface is inconsistent.

Carpet tiles will be constantly coming up, due to the fact that the adhesive will not stick to the particleboard.

Do you know what the particle board is made of? There are different types, wood, cardboard to name a couple. If it's wood then you could paint or stain for a temporary fix. You could use carpet tiles or even throw rugs. The key is to find out what your subfloor is made of.

The problem I found with particle board is it soaks up paint like a sponge. Similar to Masonite. The paint just disappears into the fibers. A wood conditioner/sealer might be needed before you prime and paint. What I did was to lay down a layer of builders felt then topped it with Luan Plywood. (The particle board was too rough textured and the Luan plywood is much smoother). The felt keeps the two surfaces from rubbing together and squeaking. I stained the Luan plywood and sealed it with 3 coats of polyurethane. Two area rugs cover most of the floor. It's holding up quite well these last 5 years. (Bedroom on main level).

Our upstairs loft we did differently. After ripping up the carpet that came with the house, we laid down an underlayment and topped it with click panels of Bamboo flooring. (We found a bargain on this flooring, so it turned out cheaper than carpeting).