If you have a mold problem on your roof and have decided to remove that issue on your own, there are some steps you should take to make sure you do the job safely and properly.
It may seem odd, but the first things you should consider will happen on the ground. You need to look to see if plants below your roof will be damaged by runoff of chemicals. If so, you can cover those plants with plastic. Another option is to mist the plants with a garden hose. Water will keep dangerous chemicals from sticking to your plants, and you can always hose them down again when you are finished on the roof.
Anytime a homeowner has to get on the roof, safety should always be the first concern.
The first order of safety is protecting yourself from the cleaning solution you will use. This means rubber gloves, a breathing mask or respirator, and eye protection.
Safety should extend to your clothing, as well. You want to make sure that you wear clothing that will allow you to work safely on the roof with mold that could be slippery. So the right clothing should include: shoes with grip, a long-sleeve shirt and long pants (that you may have to throw away when you are done), and possibly knee pads.
We recommend mixing a solution of one quart of bleach with one gallon of water and a quarter cup of trisodium phosphate. This is a powerful solution that will knock out the mold on your roof. Mix it into a pressurized sprayer.
In addition to the sprayer, you’ll also need a long-handled brush.
When you’re ready to ascend to the roof with your supplies, do it safely. Make sure you put your ladder on level ground at that it is stable. Get someone to hold the ladder while you are on it. Make certain there are no obstructions preventing you from getting easy access to the roof and that the ladder is tall enough to reach the roof and allow you to easily step onto the roof.
It’s also a good idea to bring your supplies up by rope rather than carrying them while you are on the ladder.
Once you are on the roof, walk carefully and be sure of your foothold with each step. Especially if you have a mold problem, your roof could be slick to walk on.
Start by brushing the mold with the long-handled brush. By scouring the shingles with the brush, you will loosen the mold while it is dry and brittle.
Then, at the edge of the roof and working up toward the top, spray the roof thoroughly with your solution. You want the solution running down the shingles as you spray, so it will take a good covering, and depending on the size of your roof you may need your helper on the ground to mix a second or even third batch of solution for you.
Once the solution has been thoroughly applied to the shingles, allow it to sit for about half an hour, and then you should rinse the roof well. You can rinse your roof either with a garden hose or by filling your pressurized sprayer with water.
Do not attempt to clean your roof with a pressure washer. The force of a pressure washer could do extensive damage to shingles.