Pro Tips for Exterior House Painting
By Tom Matthews
A new coat of paint is one of the most striking enhancements one can make to the curb appeal of a home. However, a home’s exterior might consist of any number of materials, as well as a combination of different materials. These various materials often require different techniques to ensure a new long-lasting topcoat. This article covers some of the more common house cladding materials, and offers professional advice on techniques to paint them.
Surface prep—If efflorescence is present, remove it by scrubbing with a wire brush. To remove heavy staining, mix a heavily diluted solution of water and muriatic acid. While wearing goggles and rubber gloves, mop the solution onto the wall and scrub thoroughly with a stiff-bristled brush. Rinse with plenty of clean water. Eliminate any source of water from behind the brick that could have caused the efflorescence.
Treat any mildew with a 3:1 water-bleach mixture, leaving it on for 20 minutes and adding more as it dries. Clean off dirt, chalk, dust, any residual particles of paint or treated mildew by scrubbing with detergent and water. Rinse thoroughly.
Scrape out and widen any cracks, brush out the dust, then seal with 100-percent acrylic or siliconized acrylic caulk. Check mortar joints carefully and repair or re-point as needed. Always wear gloves and eye protection when prepping the surface for any paint job.
Priming—Priming brick is not essential with quality exterior latex house paints or masonry paints, but priming will maximize sheen uniformity and minimize efflorescence and mildew. Use a quality exterior latex primer that is recommended for masonry surfaces.
Painting—Use top-of-the-line exterior 100-percent acrylic latex house paint in flat, satin or semigloss finish, depending on the desired appearance; or use a quality latex masonry paint.
Another option for brick paint is an elastomeric wall coating. These are exterior acrylic latex masonry paints designed to be applied in very thick films (about 10 times as thick as regular paints). They are tough and flexible, and stretch as cracks underneath open and close, which bridges the cracks and keeps water out while maintaining a nice appearance. They can be tinted to a light color, but are considerably more expensive than conventional paints. Apply two coats for maximum crack bridging and durability, and follow the manufacturer’s recommended spread rate; for best performance, this will be 40 to 60 sq.ft./gallon to achieve a minimum dry film thickness of 7 mils per coat.
The easiest way to paint brick is with a paint sprayer. For small areas such as an accent wall or fireplace, brushes and rollers will suffice. Choose a roller cover with a thick nap (1-1/4 in.) to ensure best results on brick, which is covered with nicks and surface irregularities.