Denver Roofing: Article About Algae and How To Handle It
Denver roofing companies are often called out to clean the darkened stains that appear on a roof and can extend all the way down the slope as if someone dropped a can of black paint. This kind of discoloration is usually not caused by mold or soot but rather algae, and algae spreads, so it isn't unusual for an entire neighborhood to be affected once that first home is. The good news is that algae stains aren't particularly dangerous, but the bad news is that they can quickly kill curbside appeal.
Algae travels through the air, so it's sometimes just a matter of being unlucky. Algae does require the right condition to flourish, however, and if those conditions don't exist, then the newly arrived algae will simply dissipate. Algae requires moisture and low light. Morning dew is often enough moisture. Algae usually appears first on the north side of a home because that side receives less light, but it can appear and grow anywhere where there's ample tree coverage or another form of shade.
If homeowners notice black stains, they should clean the roof as soon as possible or hire a professional to do it.
Have a question regarding roof maintenance or roofing repairs? Please ask any of the roofers from Roof Worx of Denver today.
Pressure washing is never a good idea and can actually damage the shingles being cleaned. Effective cleaning of shingles is actually much less abrasive than that and can often be accomplished using a mixture of water, bleach and trisodium phosphate and letting it sit for 20 minutes or so. Many roofing professional prefer oxygen bleach to standard bleach since its more ecofriendly.
Cleaning away the black stains is a good start, but it won't keep the algae away if the roof is prone to it. Regular cleanings are an option, but that can be costly and time consuming. One of the easiest and most economical ways to prevent black stains and even green stains is to install metal strips at the ridgeline. As water comes in contact with the copper or zinc, it picks up minute traces of the metal, which is a natural algaecide, and carries that down the roof.
There are also algae resistant shingles on the market, and these shingles are generally manufactured by mixing copper or zinc flecks in with the granules. This feature doesn't usually increase shingle cost substantially, and this method is actually more effective because it provides better coverage. Nevertheless, this option is usually only an economical option when the roof is installed or replaced.