The best time to clean the outside of your house is during your outdoor spring cleaning. Wait until late spring, after the wave of pollen is done coating your home. You can also wash your house in late fall–before the first freeze–to remove leaves and branches from the gutters.

Roof cleaning can damage shingles if it’s done incorrectly—like with a high-power power washer—but it likely won’t damage your roof if you pay to have an expert do the work. A professional roof cleaner will use a gentle cleaning solution and a cleaning method that matches your roof material to ensure the process doesn’t damage the roof. Some homeowners worry that roof cleaning will shorten the life of their roof by removing shingle particles or protective coatings, but it often extends roof life by removing plants that cause damage and improves your home’s curb appeal simultaneously.

The best time of year for roof cleaning depends on your local climate, but generally, late spring, summer, or early autumn are ideal. Plan to clean your roof on a day with dry weather and moderate temperatures.

Late spring and early summer are excellent for cleaning off grime accumulated after a snowy winter or wet spring. Summer often provides the necessary dry conditions, though in very hot climates, late spring may be more comfortable. Alternatively, cleaning in late autumn can clear away debris like leaves and branches before winter.

Avoid cleaning your roof when it is cold enough for water to freeze, as this can cause dangerous ice buildup.

To keep your PVC roof in top condition, keep it clear of debris, ensure drainage systems are working properly, and inspect it for damage regularly. Keeping the roof clear of ponding water, sharp debris, and other hazards will prevent damage. Have your roof inspected by a professional once a year to ensure the seams aren’t damaged or separated—faulty seams can lead to destructive water intrusion.