In order to kill moss and algae on your roof, bleach can be used at low pressure. However, this puts your plants and shrubs in danger because bleach is very harmful to them. Thankfully, there are a few things that can be done to protect them before you start soft washing!
Watch the weather!
You will want to watch the weather before you soft wash your house with bleach. Bleach is harmful to your plants in its liquid state, but when it has dried for 24 hours, it is now a harmless compound like salt. So soft wash your house, let it dry for a day and your shrubs and trees will be in good shape if it rains later on. But if you spray it and then the rain comes in two hours, you may put your greenery in danger because the bleach runoff will kill it.
Wet your plants beforehand
Wet your plants before you apply bleach to your roof. This will protect your plants from harmful chemical burns from the roof mixture. You can take a garden hose with a sprayer and wet down all of your plants. Your best bet is to have a power washer with a holding tank to spray down your shrubs. Using a pressure washer with a steady flow will help you get the job done quicker, since you will be able to cover more area in less time.
Tarps to cover your plants
Before you get started, you can use tarps to cover your plants. 8 foot wide tarps work well, but use nice and thin tarps, under 2mm. Take care to check on the plants since they can overheat under the tarps.
Collect gutter runoff
You do not want the water from your bleach solution to run off into the ground. So take trash bags and tape up the bottom of your downspouts. You can put cardboard underneath of the bags so that no sticks or stones will poke through the bag. Use 5 gallon buckets in worst case scenarios.
Coat the bottom of your roof first
Use a fan tip nozzle and coat the first five feet of the bottom of your roof. Then switch to a long range shooter nozzle to reach the highest peaks of your roof. When you spray the bottom first, it creates a barrier to slow down the runoff. Using the long range nozzle reduces mist, which protects the shrubbery below, and it also helps you to place the mixture exactly where you want it.
Bring two people
Power Washing a roof is a two person job. One is on the roof applying the bleach mixture and the second person is on the ground keeping the plants wet, minimizing the damage caused to them. The second person is also responsible for hose wrangling and site management, keeping the area tidy and orderly.
You take pride in your home! Show it by keeping your roof from algae, mold and other build up, not just for aesthetics, but for your health too. Call Columbia Brothers Power Washing for a free estimate to have your roof clean in no time!
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Columbia Brothers Power Washing services the following locations near Howard County, MD: