Mold on siding: causes and solutions

Why mold grows on your siding

Mold, algae and bacteria develop on exterior siding when they find three elements: moisture, warmth and nutrients. On Montreal's North Shore, these conditions are present much of the year.

Factors that promote growth

How to recognize the problem

The solution: soft washing

High-pressure washing only addresses the surface — it dislodges visible dirt but doesn't kill organisms at the root. Soft washing, on the other hand, applies a chemical treatment that penetrates siding pores and kills mold, algae and bacteria at the source. Results last much longer — often 2 to 3 years before another treatment is needed.

Prevention

After washing, a few simple steps extend results: trim vegetation near the house, repair leaking gutters, check yard drainage and consider installing zinc strips under the roof ridge (zinc leaches with rain and prevents algae growth).

Conclusion

Mold on siding is not just an aesthetic problem — it degrades surfaces and can affect air quality. Professional soft washing is the most durable solution. Contact Aqua-Net for a free quote.