Wood ceiling beams give a room a rustic feel, but you cannot easily or cheaply remove the beams if you grow tired of the look. One way around this problem is to paint the beams. Whether the beams are painted to blend in with the ceiling or given a contrasting colour, the wood finish will be covered up, and the rustic feel will give way to a look that appeals to you now.
Remove as much furniture as you can. Lay down dust sheets to cover the floor and any furniture that remains. You are painting the ceiling and should expect some degree of messiness.
Set up a ladder and dust the ceiling beams. If the beams are especially dirty, wash them with soap and water, and allow them to dry before proceeding.
Line the edges where the ceiling beams meet the ceiling with masking tape if you are not painting the beams to match the ceiling. Set the ladder aside.
Open a can of interior primer by prying the top off with a screwdriver, and pour primer into the reservoir of a roller pan. Add a small amount of the paint you haven chosen to the primer. This will tint the primer. The normal proportion is half a cup of paint per gallon of primer, so adjust the proportion downward to match the amount of primer in the roller pan as closely as possible.
Screw the paint roller onto a telescoping extension pole, and roll it in the reservoir and along the pan's raised striations for even distribution. Coat the bottom and sides of the beams with primer, using short, even strokes. Do not force the roller into the corners of the beams unless you are painting the ceiling, as well.
Set the ladder back up, and prime the corners of the beams with a hand brush in hard-to-reach places.
Allow the primer to dry for 24 hours. In the meantime, wash out the pan, roller brush and paintbrushes, using paint thinner and water, and leave these out to dry.
Apply a coat of paint to the ceiling beams, following the same methods you used to prime them. Allow this to dry for 24 hours, as well, before applying a second coat. In between the two coats of paint, wrap the roller brush, hand brush and pan in plastic bags to keep them wet instead of cleaning them.
Do not mix paint directly into the can of primer unless you are certain you will use the entire can on the current painting task. Tinting the primer will spoil it for any other colour. To minimise the amount of paint dripping down your brush, wrap a rag or paper towel around the top of the brush, near the bristles, and tape it down. Oil-based primer and paint are a better match for finished and unfinished wood beams than water-based paint. One gallon of paint covers 400 sq. feet of primed wood.