Cleaning Asphalt Shingles
Cleaning asphalt shingles can be a very difficult job to get done but it is also a vital part of your roof maintenance schedule if you wish to preserve the look and integrity of your roof. If your asphalt shingles are starting to look stained then this is more than likely being caused by fungus growth. Many homeowners believe that these dark stains are caused by pollution or even tree sap. Well I can tell you right now that these homeowners are usually incorrect in their assumptions. The dark stains on an asphalt shingles roof are usually caused by fungus growth and they need to be removed.
The types of growths that can attack your asphalt shingle roof are fungi, mold and lichen feed. When these start growing on your roof they can affect the integrity of your asphalt shingles. This is because they can cause the shingles to break down. If his happens they will no longer maintain a waterproof barrier and your roof could become susceptible to leaking. There are two types of asphalt shingle which are commonly used today. These are organic shingles and fiberglass shingles. The organic types are usually manufactured using a paper felt which has then been saturated with asphalt to make the shingle waterproof.
A top coat of ceramic granules are then embedded onto a layer of adhesive asphalt. You can purchase algae resistant shingles whereby a portion of the embedded granules contain a leachable copper. This protects your roof from the discoloration caused by algae but it will not protect your roof from moss growth, although it will slow it down. Fiberglass shingles are constructed a little differently. They have a reinforcing mat which is made from glass fiber. The reinforcing mat is manufactured from wet fiberglass which is randomly laid and bonded using urea-formaldehyde resin.
The mat is then made waterproof with a coat of asphalt containing mineral fillers. The problem with asphalt shingles is that they are prone to weathering. Over time the top layer will start to thin resulting in the organic layer becoming vulnerable to mold and fungus growth. This is when cleaning asphalt shingles becomes important. The longer we leave it the worse the problem can become. And the problem can escalate. The more mold or fungus on the asphalt shingles then the faster they can deteriorate. In extreme cases cleaning the mold or fungi from the roof will not fix the problem.
You’ll have to replace them instead. It’s better to clean the shingles as soon as you notice any moss or fungus developing. Before attempting to clean your asphalt shingles I advise that you contact the manufacturer of your shingles or contact the company who originally installed your shingles for some advise on what type of cleaning products to use. Different manufacturers often suggest particular types of cleaning products or methods of cleaning. It’s important that you make sure that you don’t use a cleaning product or cleaning method that might void your warranty if not approved by the manufacturer.
Make sure that you don’t use a pressure washer to clean your asphalt shingles because all roofing shingles manufacturers advise against this method of cleaning. High pressure washers should never be used because the force of the water can strip the ceramic granules from the top layer of the asphalt shingle. If this happens your home will become in danger of water damage.
Most people will usually higher a contractor for their asphalt shingle cleaning. If you have no experience with working on a roof then this is the option that I would advise for you as you won’t be risking your safety to get the job done. If you are experienced with heights and working on roofs then you may consider saving some money and doing the job yourself. If so you can follow the steps below for cleaning asphalt shingles:
- Mix a solution of 3 parts water and 1 part bleach in a bucket. Then add the cleaning agent, I recommend tri-sodium phosphate.
- Apply the solution to a section of your roof and then leave for 15 minutes. The best way to do this is by using a hand pump sprayer.
- Rinse the solution off the roof with a garden hose.
- Rub your fingers over the shingles. If they feel slimy then you will need to repeat the process again.
IMPORTANT: Make sure that you thoroughly hose down your roof to remove the cleaning solution. The solution used for cleaning the shingles contains bleach which can damage shingles if it‘s allowed to remain on the roof.
If this cleaning solution doesn’t work then you could try another option. Try mixing a gallon of warm water with twelve ounces of dry copper sulfate. Apply the solution to your roof using a hand pump and then wait for the mildew to turn brown. You can then use a regular broom to sweep the mildew from the roof. Finally give your roof a thorough rinsing with a garden hose.
Please remember that cleaning asphalt shingles can be very dangerous. The act of adding water to the mold and mildew on your roof can make for some very slippery conditions. Never do this kind of job alone. If you find the conditions to dangerous or you don’t feel comfortable then please don’t take the risk. Hire a professional contractor to do the job instead.