How to Install Stucco Over a Wood Frame House
Stucco is an ancient building material, dating to early Greece and Rome and Middle Eastern areas. A form was also used by early Native Americans. It is a masonry coating on a wall, today composed of Portland cement, sand and lime. It is durable, weather-resistant, can be colored on application or painted and can be used with almost any style of house. It is easily applied to masonry walls, of brick, concrete or concrete block, but can be applied to wood-framed walls, too, with proper preparation. Done right, a stucco wall on wood sheathing is attractive and long-lasting.
Prepare a wood-sheathed wall for stucco by installing a moisture membrane, fastened to the wood sheathing with a construction stapler. Put metal flashing around any windows or doors; nail it to the sheathing with galvanized nails and a hammer. Cover the wall with metal lath, nailed at stud locations with galvanized nails. Place "weep screed," a metal strip with holes in it, under the lath at the bottom of the wall to catch any moisture that gets behind the lath and allow it to drain away.
Mix prepared stucco for a "scratch coat" -- follow directions on the package for this. Spread the stucco over the lath three-eighths to half-inch thick with a rectangular mason's trowel. Scratch it horizontally after it begins to set with the notched edge of the trowel, a stiff bristle broom or a leaf rake, to form depressions to hold a second coat of stucco. Let this coat dry 48 to 72 hours, misting it occasionally with a garden hose to keep it moist.
Dampen the scratch coat with a misting nozzle on a garden hose, mix more stucco with slightly more sand in it and spread a "brown" coat over the scratch coat. Spread this layer with a trowel one-fourth to three-eighths-inch thick. "Screed" or smooth it with a long straight board dragged across the surface to smooth and even it. Clean the excess stucco off any horizontal surfaces where it fell. Let this coat dry, also misting it periodically.
Spread a final coat of stucco one-sixteenth to one-eighth-inch thick with a pointed mason's trowel. Dampen the brown coat slightly first. Finish this coat with any desired texture. Make it almost perfectly smooth, roughen it with trowel strokes or give it a "popcorn" effect. Make popcorn by putting the flat side of a rectangular trowel on an area and lifting stucco up, then smoothing the peaks of that lifting. Let this coat dry, hydrating it like the first two coats.
- Moisture membrane
- Construction stapler
- Metal flashing
- Metal lath
- Galvanized nails
- Weep screed
- Stucco mix
- Rectangular mason's trowel
- Stiff bristle broom or leaf rake
- Garden hose with misting nozzle
- Long straight board
- Mason's trowel