F.A.Q's For Your Information
What causes most roof stains?
Most roof stains are caused by the growth of algae, lichen colonies or moss that feed on organic matter frequently found on roof surfaces. The portions of a roof that receive the least amount of sunlight are more likely to have roof stains. This explains why some homes may have roof stains only on one side of the roof, typically the northern and/or western exposure or in heavily shaded areas.
LICHEN COLONIES Lichens are a fungus, usually of the class Ascomycetes, that grow symbiotically with algae, resulting in a composite organism that characteristically forms a crust like or branching growth on shingle granules. Lichens put out root-like tentacles that penetrate deep into the shingle’s organic, oil base for nourishment, eventually ruining them by creating dark spots, or pock marks where they grow. It's extremely important to have lichen colonies removed professionally to stop the damage in its tracks and prolong the life of your shingles. ALGAE Algae is a living organism that thrives on dust, pollen, and the organic materials that make up the roof. Dampness triggers its growth. Stains are usually more prominent on northern and western exposures and in heavily shaded areas. Algae grows on, under, and behind the tiny granules that cover the shingles. This results in unsightly stains and streaks on the roof. Heavy algae on roofs can super heat the attic resulting in higher home cooling costs as well as reducing the natural life span of the shingles. To get the most life out of your shingles, our trained technicians will professionally clean your roof, removing all of the algae and resulting stains
MOSS Thick moss growth with its shallow root system keeps the roofing materials damp for extended periods of time and this moisture promotes wood rot and can and does erode the asphalt shingles. Moss typically starts to grow at the top of the vertical slots between the shingles. These areas of asphalt shingles are the last place water evaporates from a roof. Moss, like lichen colonies, is quite damaging to shingles and some of the granules underneath the moss may be gone. This will be evident if once the moss is removed, the portions of the interior mat of the shingle are visible. It's important to have moss professionally removed from your roof in order to extend the life of the shingles.
If left untreated it will become so thick you will not see your shingles in many areas. I've seen some situations where it looks like a roof is covered with green carpet.
What is the best way go about treating a roof with lichen and/or moss? Well, in most cases it should be handled in the same manner as the black algae roof stains (or "roof mold"), which has already been described above. A pre-treatment EPA approved algaecide / fungicide solution applied with non-pressure methods will kill lichen and moderate moss growth. It usually dies and turns a whitish color within minutes. Unlike black algae stains which come off in the rinse phase of the cleaning, dead lichen and moss will require a few days dwell time before rinsing off the roof.
To summarize, black roof "mold" stains (algae) should come off immediately if using the proper methods. White or green lichen and moss, on the other hand, will be killed with the same chemicals but will need a few days of dwell time to insure full kill. You would be wise to keep your feet safely on the ground (good idea) t and check for a reputable roof cleaning company. It's likely a company in your area that knows how to remove your roof algae using no/low pressure cleaning in a professional and safe manner.
Your Checklist for Professional Roof Cleaners...
So, your ready to hire some professional roof cleaners. Your spouse has been complaining to you that the black roof stains are ruining your curb appeal, and after reading and researching you now understand that it's also an issue of restoring your roof's health and longevity. You need to know how to find a roof cleaning company that will do the job right. Here's a general checklist for what to look for in a roof cleaning contractor.
- First of all, you would be wise to find a roof cleaning service that uses non-pressure methods for roof stain cleaning. You should know by now that high-pressure ruins your shingles. Certified, professional roof cleaners know that black algae roof stains can be completely removed with the gentle application of a EPA approved Algaecide / Fungicide product and / or a chlorine-based solution followed by a non-pressure rinse. If you come across a contractor that wants to clean your roof with a high-pressure,cross XXXX them off your list.
- Professional Roof Cleaners know that your whole roof needs to be cleaned, not just the areas where black stains are visible. If you can see stains in any one area, that's usually an indication that algae is already taking hold over your entire roof. It's only after the die off that they become completely visible everywhere.
- Find a roof cleaning service that will clean your roof with a 2 person team. While it's possible to clean a roof with one person, the ideal scenario is to have two roof cleaners on site for your job. One cleaner to apply the chemical and do the rinsing on the roof and the other cleaner on the ground to direct cleaning, perimeter rinsing and just in case the roof-man needs assistance.
- Always be sure that the contractor has liability insurance. This is true for any home improvement job. It not only protects you but it weeds out the handyman / pressure washer types who don't understand the proper roof cleaning anyway.
- Always ask for a few references that can vouch for them. It's also a good signal if they have their own before and after pictures to show off, either in a portfolio, brochure or website.
Roof Stains Should Be Cleaned With No Scrubbing
- Some potential customers who want their black roof stains removed, sometimes think the roof should be scrubbed clean with a hard-bristle brush and some sort of cleaner. This "method" might seem to make sense, but it's does not and I'll tell you why.
- I can guarantee that if you clean your roof stains with aggressive scrubbing or agitation, you're going to loose tens of thousands of shingle granules in the process. With enough force they'll pop right off of asphalt shingles, which is why I also do not recommend roof cleaning with a power washer either. Granules are vital to your roof's health. They reflect sunlight, that keeps your attic cooler and your AC bills lower. If you think your attic is hot in the summer just climb into one that has a roof that is missing a lot of granules or is covered in black algae stains. Basically, the faster your roof loses granules the faster it will lose its integrity, and the faster you'll need to get a new roof.
- The other reason you shouldn't be scrubbing or pressure washing your roof stains is that if your contractor is using the correct chemicals then no surface agitation is needed. You simply spray on the chemical with the help of a non-pressure pump, allow several minutes dwell time for it to kill the algae, and then rinse gently. Use the right roof stain remover without pressure and you will extend and restore your roof's healthy lifespan.ARKANSAW ROOF RENEW,LLC.-TheANSWER