When painting your fibreglass porch columns, keep in mind these important points. Unlike wood, fibreglass is nonporous, leaving it unable to absorb the adhesives in paint. You must prepare the column, using abrasion techniques, or it will inevitably shed its new finish. In addition, because porch columns are located outdoors, they are exposed to varying temperatures, so use a paint that can expand and contract without cracking.
Clean the fibreglass porch columns using a pressure washer equipped with a low-pressure tip. Wait two to four hours for the columns to dry.
Promote adhesion by abrading the fibreglass porch columns with sandpaper. Scour the columns until they feel slightly coarse.
Cover areas adjacent to the columns with professional painter's tape. Cover the porch with heavy-duty fabric dust sheets.
Coat the sanded fibreglass porch columns with acrylic latex primer, using a roller stocked with a nap cover. Use a paintbrush, manufactured for use with water-based latex, to apply primer to areas of the porch columns inaccessible to the roller. Wait three hours for the primed columns to dry.
Wash the roller and brush with water.
Coat the primed fibreglass porch columns with acrylic latex paint. Apply the paint as you did the primer. Wait two hours for the painted columns to dry. Add an additional coat if you can see the base primer showing through.
If you require a step ladder to access higher portions of the fibreglass porch columns, read the safety instructions on the side of the ladder before you climb it.
Never paint unabraded fibreglass porch columns, or the finish will fail. Never paint bare fibreglass columns, or the paint will peel. Do not use a latex paint on porch columns, or the finish may crack as temperatures fluctuate.