How can I clean the exterior stucco on my house without damaging it?

To keep stucco attractive for many years, it is important to provide routine maintenance to the exterior of your home. Periodic washing of soffits and walls are the most important items of care with regard to stucco, as it will help avoid the potential buildup of dirt and mold. This is also a good practice for any type of building exterior, whether constructed of wood, masonry, steel or any other material. 

Cement plaster walls, or stucco, provides a decorative and protective covering for your home. Stucco provides a tough and weather resistant surface, however, is known to be very porous and can absorb dirt and stains more readily. Stucco usually has a textured surface, which allows dirt, grime and mold to settle into the surface crevices. What starts off as a beautifully crafted finish to the exterior of your home, can over the years, become dreadful if not properly maintained. 

The preparation for cleaning your exterior surface is very important. The very first thing to do is to ensure that there are no cracks, or chips in the stucco. Cracks encourage the seepage of water into the pores and potentially damage the entire wall down the line. Any crack or chip must be filled in immediately and given sufficient time to dry out. 

Though you’re better off leaving major stucco repairs to a mason or stucco specialist, you should be able to handle fixing most holes and cracks if you have do-it-yourself experience. The way you make these repairs will depend upon the nature of the damage, such as the size of the hole. 

When a house settles over time or shifts because of heavy winds or earthquakes, the stucco siding cracks. The proper way to repair these problems depends upon their size. 

Very fine, hairline cracks are very easy to fix. If they are super-thin, a coating of acrylic latex paint that matches the siding will probably do the job. If they are a little too wide for paint to fill the crevices, fill them with latex caulking compound first. Allow this to dry thoroughly, then paint the surface with acrylic latex paint. 

When starting your cleaning project, start with using your garden hose to rinse any loose debris and residue from the stucco from bottom to top. This will prevent dirty water from being absorbed into the surface area below. Dry stucco is very absorbent and can get even more stained if dirty water is dripping down onto it. 

Next, attach your pressure washer to the water supply or hose. Get adapted to the movement of the wand and the kick of the sprayer by practicing in an area that you won’t damage. You don't want to be on a ladder when you pull the trigger on your power washer for the first time as it can throw you off balance. 

Wear gloves, long sleeves and safety glasses, then test an inconspicuous piece of stucco. You should find an area normally covered by rocks or a fence post to avoid damage to an easily seen area. It is important that you know what your pressure washer is capable of before beginning your project. 

Once acclimated, set the nozzle to a fan pattern and methodically pressure-wash the stucco, starting at the top of the wall and working down. Keep the wand moving so you don't dig a hole in the stucco. To protect the texture when you clean the stucco, use a low-pressure spray tip, hold the spray gun or wand so that the spray hits the stucco at a 45-degree angle and keep the nozzle at least 24 inches from the surface. 

For dirtier areas, apply detergent with a pump sprayer. You can consult with your local hardware store professional to select just the right treatment. If you notice hard to clean stains, use a soft brush, and a rust or mildew removal solution. Start from the top of your home and work your way down to the bottom. With all chemical applications, only do a section at a time so that the surface of the Stucco is not damaged. Most importantly, rinse off detergent from the top to the bottom. 

For a large project, or if you’re not comfortable doing this work yourself, contact a professional power washing contractor. They will have the knowledge, materials and equipment to provide the services required to restore your home’s exterior. Remember to ask for references and insurance certificates. Licensing for this type of home service is not required so please be careful when hiring a professional. 

Alan Poritz, President Clean Swift Maintenance, Inc. 
(718) 442-8600
www.cleanswiftnyc.com

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