How to Stucco House Siding

Stucco is an adhesive, cement-based coating used to finish house walls both indoors and outdoors. Older stucco finishes used to be made of marble or other hard rock powder instead of cement. Select a cool-to-warm stretch of weather for your stucco project--try to avoid hot, sunny days if possible--and be prepared to protect the work-in-progress from rain if it comes. Plan on loitering around the house for the two or three days after your project is done, because you'll need to mist the stucco siding almost constantly as it dries.

Instructions

1. Cover the house siding with 15-pound roofing felt nailed into place, then nail 17-gauge metal netting over this. The felt and netting must completely cover the area to be stuccoed.

2. Mix six parts medium sand, two parts Portland cement and one part hydrated lime in a wheelbarrow or large tub. Use a clean stick or mixing paddle to thoroughly blend the dry or damp ingredients until they achieve a uniform consistency and texture, then slowly add clean water until the entire mixture achieves a "plastic" consistency. If you form a ball of this stucco material and set it on a flat surface, it should hold its shape.

3. Blend Portland cement powder with water in a separate, smaller container to form a thick slurry with a paint-like texture. This is your cement paint.

4. Mist the felt and wire surface with water from a spray bottle, then use a paintbrush to spread your cement paint to the surface to be stuccoed.

5. Use a steel trowel to apply a 1/4-inch thick layer of stucco on the cement paint. Work one small section at a time because the cement paint must not dry before the stucco goes on.

6. Monitor the texture of the stucco as you work. It should adhere easily to the cement paint and the surface beneath; if the stucco falls off it is probably too dry--try adding a little more water to the mixture.

7. Continue stuccoing until you've covered the entire area of house siding you set out to stucco. You can bend the roofing felt and mesh into shape around corners if necessary.

8. Smooth the stucco out with a finishing trowel or, if you prefer, scratch designs and patterns into it very lightly--think of it as a blank canvas.

9. Spray a light misting of water onto the stucco, doing your best to keep it lightly moist for the next two or three days as it dries. This helps keep it from cracking.

10. Protect the stucco siding with plastic sheeting if it rains, then remove the sheeting once the rain has stopped to allow air circulation and drying again.

Tips & Warnings

• You should be able to work from the same batch of stucco all day long, although the cement paint should be mixed and used in small batches throughout the day to keep it from drying out as you work. To calculate how much stucco mix you need, calculate the felt-and-mesh covered area in inches. Divide this number by four. The resulting number is how many cubic feet of sand and cement mixed together should go into your stucco mix.