Stucco lasts from 50 or 80 years. In order to live out its expected lifespan successfully, stucco tends to require a modest amount of care and attention. For indoor stucco, a new paint job may be all it needs. But, with exposure to the beating summer sun, the howling winds of winter, and simply the dirt and dust kicked up by passing traffic, it’s only a matter of time before stucco siding needs minor repair or, at the very least, a simple cleaning.

Simple cleaning may be all your exterior stucco needs if not repairs are necessary. Cleaning indoor stucco usually takes nothing more than water and a bit of elbow grease. Simply scrub the stucco with a dampened nylon brush to saturate the surface, then rub away the buildup with a moistened microfiber cloth (or clean cotton rag).

In extreme cases with deep stains, experts recommend a chemical solution known as trisodium phosphate, or TSP. Available at most home centers, be advised that safe use TSP requires that you take proper precautions. Ventilate the area by opening windows and running a fan. When working, wear the right gear (rubber gloves, protective eyewear, and long-sleeve clothing).

Combine the TSP with water in a bucket, diluting to water-to-TSP ratio of 15 to 1. Apply the TSP to the affected area by means of a nylon brush and allow the stucco an hour or two to dry.

Outdoor stucco tends to get a lot dirtier and requires more frequent cleaning. Use a garden hose (equipped with a spray nozzle) or a power washer (on its lowest setting). First, with your chosen tool set to spray in a mist formation, saturate the stucco from bottom to top. Then, switch to a more concentrated spray and proceed to clean from top to bottom. After spraying, check the stucco for any lingering buildup and if you encounter any buildup, dislodge it with a stiff-bristle brush, being careful not to scrub so vigorously that you grind down the stucco. If blemishes still remain on the siding, apply diluted TSP with a pump sprayer or a hose wand with a built-in soap reservoir. Allow sufficient time for the stucco to dry and finish up by rinsing the stucco surface one last time.