Here is a little background on how I started Roof Sparkle. A company that’s making cleaning products asked me if I could make a video for some of their cleaning products. Now I won’t go into details on who they are but they had a roof cleaner that involved the use of a power washer. A big red flag in my eyes. Being a contractor for years, I knew right off the bat that was a big no-no.
So the next question I asked myself what’s that black stuff on the roof. Well, it’s mold. And what kills mold, bleach right? Well, as true as that is bleach is only made up of 5-6% Sodium Hypocrite. And that’s great for your whites and around the house but not on your roof.
For the roof, you will need something a lot more powerful. Some of you may know it as pool shock. This is made up of 12% by weight “Sodium Hypochlorite”. But because it’s as thin as the water it will run right off the roof and not really have the time (five minutes) to do its job. So we have to thicken up a bit. The best way, add some liquid dish soap to the mix to help the SH stick to the roof for more than one second. You can go into any pool supply and ask for a gallon of shock, for about $4.00 per gallon. This is just a heavy-duty version of household bleach. And no Walmart does not sell this or the big box stores. This method will remove algae from a roof.
Now, of course, we buy it from the manufacturer and by the truckloads at a time.
Applying It
When we started we used a regular bug sprayer. Use a three gallon pump sprayer, use one gallon of SH and two gallons of water (H2O) add about 4 oz. of liquid dish soap and spray from the roof top working your way down.
DON’T
- clean your roof when it’s super hot out in the baking sun. It will kill the SH and dry before it’s clean.
- Don’t touch the SH with bare hands. Wear gloves and eye protection.
- Don’t spray your roof down first with water to cool it off.
Comments ( 173 )
Hi,
I have a camp in a very remote area of Maine. It is covered with moss. I am curious, should I simply use your suggested solution (Pool Shock with Water and dish soap-surfactant) and then brush? I don’t have a hose and spigot handy, so I cannot rinse off the solution after spraying it on with a pump sprayer. Any other suggestions would be great. Oh yea, and I’m going to use the copper flashing for future moss elimination.
That would be Ok. However just be careful with getting in your eyes without water nearby to clean yourself.
Thanks for the great info, Dominick! I’m looking forward to trying this out. One question though – I have a bottle of Sunlight dish soap that says on the back ‘do not mix with chlorine bleach’, but my bottle of Dawn does not say that. The warning on the first has me worried though! What brand have you used? Have you ever used Dawn? I’d hate to have some I intended chemical reaction! Thanks.
Yes we use Dawn most of the time. But remember you’re not using the soap to clean. It’s only there to help hold the SH on the roof longer rather than being too thin and just running right off.
I just did my siding on the north side of my house, using Dawn liquid and a 4 litre sprayer. I have never seen my siding look so great since the day it was installed! Thanks so much. I’ve tried scrubbing some of the stains before with different products, to no avail. I can’t believe this was so easy. The only unintended consequence is that my wood deck underneath is now really clean where the runoff was, so I’m going to spray the whole thing. This works out really well, as I need to re-stain it anyway. I can’t wait to try this on the roof. I had a quote to get my shingles redone and it was going to be $4000, when really there’s nothing wrong with them other than black streaks. This is a much better way to go, and saves my wallet. Thanks again!
Just want to say…you are awesome! We are about to purchase a 1920 home and I have been watching all your videos for DIY….the best out there! Thanks a bunch for doing this! Cleaning my roof will be one of the first things I do!! (then finishing the rewiring of old knob and tube the previous owner started…yikes!)
What mix I need to remove this moss on cedar roof ?
It’s really the same mix. But I would remove the moss by hand first. All the mix is going to do is kill it and clean the roof.
This might be a silly question, but if you are diluting the 1 gallon of pool shock that is 12% SH with 2 gallons of water, doesn’t that reduce the % of SH to 3%? Which is less than bleach that is 5-6% SH?
One would think so. However this is a very common mistake. You are thinking outside the box. It’s very important that you mix it the way I stated. This is by weight. not by volume like baking a cake.
I have the same question as Dean how much of a square foot area will the 3 gallon mixture cover, assuming I’m using the hand spray and not a hose. Thanks, so glad to have found this solution.
It’s all going to depend on the sprayer, how much is that sprayer pushing out. And how bad is your roof. for the most part you’ll get about 900 sq ft for three gallons.
We tried the solution on our roof which is pretty old 20+ and did not see a big difference. Could be the roof is permanently discolored. I was also wondering if the solution it self might be the problem..it says 10.5% instead of the 12% you recommend. Would the 10.5% be the problem? That’s what our local pool supply had. BTW your website is amazing can’t thank you enough.
Yes very much so. You really need it stronger. I can’t tell how many times I’ve seen that before. It really does make that much of a difference. Without seeing your roof it’s a little hard for me to say. And thank you very much. I do work my butt off on this site. Like right now at 5:55am lol…
My question is when you rinse off the roof, Does the gutter runoff from the shock hurt the lawn (I’m guessing it doesn’t as long as it isn’t 95 degrees out)?
Appreciate you explaining this process to fix a problem many of us have! Thanks, George
NO, the SH will kill plants, grass and anything in it’s way. Rinsing good is very important. We wet down all the plants, clean the roof and rinse the plant and grass again.
I bought 12.5% SH today after watching your video. I have a 2 gallon sprayer what would be a good mixture to use ? Also I don’t have a lot of moss on the roof. Thank you for the awesome video!
1/3 sh 2/3 h2o
So glad I found this. I’m purchasing a home and thought the roof was in need of replacement. The roof has that ugly black stain but only on the North side as you said. The other side looks brand new. I’ll be using these techniques right after moving in!
Thanks!
Glad I could help out.
Will spraying a solution of hydrogen peroxide/water,before or after, neutralize the affects of the sh/water for the plants and shrubs around the house?
kind of wanting this to be foolproof with some customers, thx
Just enough water is fine.