Bob & Rodman — When to paint or to stain

Paint isn’t paint when it’s a stain! Since spring cleaning can often involve painting, it’s helpful to know where to use paint and where to use stain. Both finishes are composed of the same three components: solvent, binder and pigment. With stains, however, the binder (the part that produces the surface film) is only a small part of the mixture. Therefore, stains penetrate the surface while paints produce a more evident surface film. Why, in exterior finishes, would you use one rather than the other?

Paint, especially acrylic latex, is long lasting. On suitable surfaces, with proper preparation, quality latex paint will have a service life of up to 15 years. Oil-based paints will show their age at a little more than half that estimate. Opaque acrylic stains are on par with paint, but transparent and semi-transparent stains are more of a 5-year proposition. If reduced maintenance is high on the list, acrylic latex paint is your choice. Darker colors fade faster, and Southern exposure increases fading.

There are some applications, however, where stain trumps paint every time. Stains are more breathable, so they perform better on decks where moisture considerations are in place. Cedar, cypress or other high-tannin siding impedes paint’s bonding requirement and is better treated with a stain. If the effect of surface grain is desired, semi-transparent or transparent stains may make their more frequent reapplication worthwhile. With transparent stains, you get the full effect of both wood grain and natural color, but at the cost of higher maintenance.

Rough-surface siding, such as T-111, responds well to the greater penetration of solvent-heavy stains. Siding or roof shingles fall into this category as well.

Whether using paint or stain, surface preparation is the key to success. Chipped, loose or “alligatored” substrate must be removed in any case. When using oil-based paint, even a cracked, old paint surface can lead to moisture hot spots and blistering of the new finish, another argument for the more breathable acrylic latex paints or stains. Speaking of moisture, it’s a good practice to let pressure-treated decks season until they are dry to the touch and have lost the clammy feel that indicates interior moisture.

While you can apply opaque latex stain over latex paint surfaces (the solid-color latex stain is a film-producer, too), Herculean effort is required to strip paint residue should you decide to use transparent or semi-transparent stain on a previously painted surface. It’s a good idea to decide on the cosmetic effect you are after in advance and tailor the finish to that requirement.

One other factor to remember in stain application: it penetrates! Be ready to go past a two-coat application on especially dry surfaces. You can brush, roll or spray either paint or stain, but check the individual manufacturer’s instructions to get the best effect. The paint and stain producers have spent a lot of time composing helpful guidelines, and they want you to succeed. Honestly, nobody will think less of you for reading the directions.

Tune in to The Bob and RodMan Home Show every Saturday from 9 to 11 a.m. on 920 AM-WGKA to learn how to improve your house or apartment. RodMan is a certified home inspector, knows residential property appraisal and is a hands-on home renovator. Bob owned a roofing company, has reclaimed distressed properties for years and has Master Licenses as a plumber, electrician and HVAC mechanic. www.bobandrodman.com