Roof Cleaning Expectations vary Roof by Roof
It’s a common roof cleaning question that we hear from homeowners who just bought a home that has a stained roof:
Will a Roof Stain Cleaner remove all the black streaks, lichen, roof mold?
I want my roof to look like new!
The short answer is that a Roof Shingle Cleaner will improve the appearance of your shingles, but no cleaner is capable of making a roof look brand new.
But a roof cleaner will improve the appearance for very little investment, which makes an attempt at roof cleaning an essential step before deciding to buy a new roof.
So let’s explore what factors affect how well a roof stain cleaner will work.
Roof Stain Severity
Roof Stains go by many names: Roof Algae, Shingle Lichen, Roof Mold or Black streaks. The roof stains have a very predicable triangle roof stain pattern and the longer the stains are on the roof shingles the more effort that will be required to remove them. In some cases we have heard from customers who have had stains for 10yrs, these stains will be VERY difficult to remove. In the end, consider that for every year a stain has been present on the roof it will reduce the effectiveness of a roof cleaner, by 4%. So if you have had stains for 10 years, consider that a roof cleaner will improve the situation by 40% versus if the stain was only 1 year old, the results would be 96% better.
Roof Shingle Age
The age of the Roof Mold Stains is not the only consideration when trying gauge how much better a roof will look. The age of the roof shingles themselves is a factor. First consider that a shingle itself has a useful life, which is typically expressed by its warranty. In other words you can buy a 20yr Asphalt Shingle, or a 30yr Architectural roof shingle and the expectation is that by the end of say 20 yrs, the shingle will need replacement. With that in mind consider that at 10yrs, the shingle is 50% used or half way to needing replacement. The tell tale sign of shingle age is the amount of shingle granules that are washed into the gutters. Just heavy rain is capable of rinsing more granules the older the roof becomes.
So how does shingle age affect my results? The older the shingle, the less it will respond to cleaning attempts. So a shingle roof halfway through its life (say 10 yrs old) will not respond as well to roof cleaning as a 2 yr old roof. The percentages increase as the age of the shingle increases, but a good rule of thumb is every year of age the shingle has reduces the expected cleaning results by 3%, so a 10yr old shingle will show 30% less improvement over a 1 yr old roof shingle.
Your Roof Cleaning Technique
How you clean your roof makes a huge difference as well. Removing roof stains requires a quality roof cleaner solution and a reasonable amount of rinse pressure. The roof cleaner makes it easier to remove the debris from the roof stains. The more pressure used to rinse the roof stains, the faster the improvement will be noticed.
Some roof cleaners advise to allow the rain to do the rinsing, but that can take a very long time.
In general if you can rinse the roof stains off from standing on the roof you will experience the BEST roof cleaning results. If you are attempting to rinse from the gutterline then the results are going to be decreased 10-20% for every 10 feet away from the gutter because of the reduction in rinse pressure. Ideally a pressure washer with a low pressure fan tip to do the rinsing, produces better results than just a garden hose.
Roof Cleaning Frequency
The more often you clean your roof, the less it will respond to cleanings. Roof Cleaning is more stressful than just leaving it alone, much like clothes, over time they will wear out with repeated washings. Reduce your expected results by 10% for each time the roof has been cleaned.
What improvement should I expect?
Set your expectations based on your own home. Let’s say you have a 20yr roof that is 5 yrs old with stains that have been present for 2 yrs, and you can clean the roof by standing on it, and the roof has never been cleaned. Start at 100% and subtract 15% for the roof age (5yrs * 3%) and subtract 8% for Roof Stain age (2 yrs * 4%). That gives a 77% improvement expectation for your roof when cleaned.
What about much older roofs, stains, repeat cleanings, or you don’t want to get on the roof? All of these things will reduce the expected results. For example a 15yr old roof, with 8yr old stains that you clean from the gutter: Roof Age 15yr * 3% = 45%, Stain Age 8yr * 4% = 32% roof cleaning result reduction of 77% meaning that the roof could be improved by 100% – 77% or 23%. Of course these percentages are guidelines. The main message: no roof cleaner will work 100%, but a quality roof cleaner will make your roof look better!!
So should I try to clean my roof?
When it comes to dealing with roof stains from algae, lichen, mold moss or whatever you decide to call the black streaks, In the end, you have 3 options:
- Live with the roof stains
Yes, the roof stains will get worse, but you don’t have to expend any effort or dollars
- Try to reduce the roof stains with a roof cleaner
Very low cost, compared to roof replacement, but does take effort: The older the stains or roof, the more effort it takes
- Buy a new roof
Buying a new roof will have a VERY high cost (over $10,000), and removes the stains, but the stains will return in time, so make sure you use a Roof Armor Stain Prevention strategy.
Roof Cleaning produces the MOST improvement for each dollar spent