Proper Application for Stucco Over Wood

Wood Protection

• The first and most important aspect in properly applying stucco over wood involves protecting the wood from water damage. Wood siding helps protect your home from the elements. Most products designed for the exterior portion of your house can withstand sunlight, wind and rain for a period of years, occasionally requiring a new coat of paint from time to time. Although this exterior wood endures a certain degree of abuse, it is no match for the heightened risk of continual dampness posed by an overlay of stucco. Stucco can trap moisture next to the wood, causing the formation of mold and rot. A weather-resistant barrier, usually in the form of plastic sheeting, helps seal out water. Check with your municipal building department for any regulations or codes in your area that govern the application of stucco siding. Your local codes may require more than one layer of weather-resistant barrier material.

Water Penetration

• Water may seep around openings, such as windows, vents and doorways, eventually causing damage to the underlying wood structure. Sealing around these openings prior to installing the stucco helps protect your home from water damage and unseen mold and mildew growth. Use silicone caulking and house wrap tape around the edges of windows and the weather resistant barrier to help seal out moisture around these openings.

Lathe

• Applying the lath to a wooden surface for stucco application is similar to applying the lath to a cement board surface. Holding the lath slightly off the surface of the weather-resistant barrier adds another layer of protection to the underlying wood. Furring nails or self-furring lath can help create this necessary gap.

Stucco Coats

• One of the most important aspects in applying the stucco over a wood surface is to allow sufficient time for curing between coats. This may take several days, depending on temperature, humidity and the thickness of your product. Follow the mixing and application instructions on your brand of stucco. Do not exceed 1/4 inch in thickness with each coat of stucco. Use a scrap piece of wood and lath to practice your application technique before applying the stucco to visible areas of your home. The number of coats you require depends on the look you desire. Stucco finishes generally require between three and five coats.