DIY Tip From Pro – How to clean mold and moss off a Roof with Bleach

How to get this Ugly Black and Green stains off your shingled Roof

Sometimes an older roof really is not as old as it looks.  Moss and mold can start to grow on your roof causing the roof to look very dirty and old.  Often times a little roof cleaning can bring back the original color of the roof and restore the new look of the roof.

Before and after photos of a roof being cleaned.

Clean your roof with bleach
Using a little soap and a bleach product will get your roof looking like this. See the top half of photo is section of roof already clean and the bottom section of roof is still in need of cleaning

This roof is being cleaned and is not finished yet,  but you can see the dramatic difference of the roof.  If you spray bleach and a mixture of water and maybe a little dish soap you can get similar results as this.    The top half of the roof has been cleaned and the bottom half is before it is cleaned.  The dish soap helps the bleach stick to roof a little while longer.

How to spray Bleach On your Roof for DIY roof Cleaning

It really is easy to clean a roof off with bleach.  As a professional there are a lot of cleaning products on the market but most of them are much more expensive than simple bleach and are not nearly as effective as bleach and water.

Here is another photo of a roof in the middle of being cleaned by me.

Roof cleaning stencil on dirty shingles
This roof was very dirty and started off with us spraying “roof cleaning” on the dirty section of roof

As as you can see a black and dirty roof does not necessarily mean the roof is old and needs replacing, you can restore the roof with a little bit of bleach and water.  We actually added a little TSP to the solution to make it a little more potent.

A very important step to the process is to make sure you add enough bleach to the solution to get good end  results.  If you don’t add enough bleach you will not break down the mold and black streaks enough to loosen the dirt and grime from the shingles.  If you don’t break down the moss and algea enough then you will have to use more pressure to spray the dirt off the asphalt shingles which is not good for them.

Keep in mind they pour tons of Bleach in swimming pools and really is used in farms to keep inside of  pipes clean for drinking water for animals.  Now after the bleach solution is dried on the roof you want to use s low pressure rinse to get the black stains off the roof. Steam is a good source of low pressure rinsing agent and can help clean the roof and kill the algea.  Steam also Can help reseal the shingles buy melting glue lines back together but if you don’t have a steamer use A very low pressure rinse to get the mold off your roof.

*Hint* If you have to use a lot of pressure then you may not have put a strong enough bleach solution on the roof. Keep In Mind shingle manufactures recommend cleaning shingles with bleach so it is not bad for the roof.   Make sure you use an outdoor bleach which is much stronger than most household bleach and if you are worried about plants below make sure you wet them before and after spraying the roof.  Also the strongest bleach you can probably buy is pool shock from a pool supply place.  This is what they put in pools you swim in so how bad could it really be after it is dried?  Just make sure you dilute the pool shock with water to help activate the chlorine salts.

Please feel free to comment if you have any questions or call us if you need your roof cleaned in Connecticut.

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