Oak vanities that once held sway as a top choice of builders tend to make a bathroom look dated these days. Although oak is known for having a highly visible grain and large pores, which makes it more difficult to get a smooth look with paint, it is possible to give an oak vanity a modern sleek look with a few coats of paint.
The type of paint should match the desired finish. For a pickled or whitewashed look, choose chalk paint. For solid color that still shows the grain of the wood, use an oil-based enamel paint; to hide the grain of the wood and create a smooth glossy surface, use a water-based enamel paint. In any case, the paint should be either a high or semi-gloss so that it can be cleaned easily and will stand up to regular use.
Clean the vanity thoroughly using trisodium phosphate, known as TSP, to remove dirt, oils and grime that stop paint from sticking. Lightly sand the surfaces to be painted with a medium grit sandpaper and wipe away the dust created by sanding. Tape off any areas that won't be painted or that are next to walls and counter tops. Lay plastic sheeting or newspaper on the floor below the vanity to guard against drips. Remove the hardware, doors and drawers. Lay the doors across a pair of sawhorses for priming and painting.
Filling and Priming
If you don't want the wood grain to show, it may be helpful to apply a filler prior to priming and painting. This will fill in the porous areas and create a smooth surface. Filler is usually brushed on like paint and the excess wiped away with a soft rag once it starts to dry. Unless you are using chalk paint to create a pickled look, apply an alkyd primer that will both help the paint adhere to the oak and prevent tannins from seeping out of the wood and through the paint.
For solid coverage, use a brush to apply paint to corners, edges and decorative areas that a roller won't cover. Then use a roller to paint the remaining areas. Let the paint dry according to the manufacturer's directions, typically about three hours. Apply a second coat the same way and let it dry for at least 24 hours before using the vanity. For a pickled or whitewashed look, brush the paint on and then wipe it away with a clean rag. Apply as many coats as necessary to get the desired appearance.