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 )
Dear Admin,
Firstly, thank you so much for still answering questions to this old thread. Very much appreciated. And I got a lot of info about protecting plants and other considerations as well.
My question is regarding the same question posed by Garbonzo and some others regarding using household bleach ~6 – 8% SH instead of the pool shock which is 12.5%. I guess some pool bleaches also use Calcium hypochlorite instead of SH (= sodium hypochlorite = NaOCl), but we’re only concerned with SH.
I see that you mention that it is by weight. So 12.5% w/v (weight/volume) pool shock will be the equivalent of 12.5 g NaOCl / 100 mL of water. So 12.5 g of SH was dissolved in water, and more water was added until the entire solution totaled 100 mL. Household bleach will be 6% = 6 g / 100mL of water. Then the rest fits what Garbonzo was saying, wouldn’t it?
12.5 g NaOCl / 100 mL of water = 500 g / 4 L of water (assume 4 L ~ 1 gallon)
Add 2 more gallons to dilute (~8 L), which gives 500 g / 12 L (3gallons),
500g / 12,000 mL = 4.1667 g / 100 mL which is 4.1666% w/v (weight/volume)
which is less than the 6% w/v of household bleach.
Or, are you’re saying that it’s (w/w) weight / weight?
12.5% w/w = 12.5 g SH / 100 g water. But 100 mL of water weighs exactly 100 g, so the rest is exactly the same.
We could also look at density, but it gets kind of stupid. The density of 12.5% w/v SH solution in water is ~1.2 g/mL , so a little denser than water at 1.0 g/mL. The density of 6% SH is 1.1 g/mL. There might be varying amounts of NaOH, NaCl, etc, but it’s only a little bit of the product so let’s focus solely on SH. But not really much difference between 1.1 and 1.2.
I read in some pool forums, where pool owners will use regular bleach because it’s cheaper for the same amount of Chlorine, but admit that it’s much bulkier and heavier and pain in the butt, so prefer the more concentrated formulation. Also, I guess Calcium hypochlorite or whatever pool product has some additive or something that releases the chlorine slower, so that it’s not all gone by the next day. I assume that for a pro like you who has to lug lot of liquid volume around, it would make more sense to carry a more concentrated form of chlorine, then just add water at the site.
Of course, the simplest thing for me to do would be to just try it and see. If it shows visible improvement in ~10 minutes, it works. If it doesn’t, it doesn’t.
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Anyways, I also noted that you were using a 3 gallon sprayer when you first started. I was looking at chlorine safe sprayers (I guess because they use Viton gaskets). So thank you for all your info, and your valuable insight is giving me the courage to try it DIY style.
Thank you,
Always my pleasure.Thank you so much for your very long and nice post.
Is the SH formula the same one you used to remove moss as well?
Yes very much so.
I have a very steep and dangerous multi roofed home in the Puget sound area. Walking on most of my roof is impossible because there no anchors. Your moss killer sounds like what I need as I am starting to get a carpet on the north and west sides. I have a pressure washer that has a small tank on it that could deliver the stuff onto the roof. I just wanted your opinion on putting it on that way. will that work with the really wide attachment. Thank you for your help. Leroy
Over time that would or could work. But you could be adding to much water to the mix at that point. However the SH would end up eating your power washer. The best wat is to stand on the gutters edge for a pump up system. Something like what Roof Sparkle uses. Unfortunately that info I can not give out just yet. And needless to say it’s not cheap. And the over spray you would get from a power washer would be way to intense.
I used the 3 gal. Solution on my roof. 100%improvement. I still have “black areas” I just did it yesterday. Should I go back and respray those dark areas? Also, I mix d sprayer on my deck and now I have bleach spots. Is there a home remedy for cleaning my deck? It is free treated wood.
Thanks
Either your roof was really bad or your mix wasn’t mixed strong enough. Yes I would do it again.. As far as your deck, simply clean it with the roof cleaner.
Hello, I was just wondering if this solution would work on any other type of roof, like clay tiles or cedar shakes and stone slate roofs. Thanks
Yeah sure. It’s all about the mold on the roof you’re cleaning. However on cedar you MUST really rinse it good.
We tried this technique over the weekend. I was amazed at how quickly the moss died. I left it on for a day. I used a brush to loosen some of it up. After I rinsed the moss off, there is still a fine light green ‘moss fuzz’ on the roof. Not sure if I should try and scrub it off? I don’t want to strip the rocks off the shingles and cause the roof to leak. Suggestions?
Now everything is dead. Give it time to dry up and fall off.
I”m in Oregon. Can SH be applied when it wet outside? Or must the moss be dry?
If it’s wet you’ll just need a little stronger mix. But dry is better.
BTW stick with straight sodium hypochlorite and avoid the calcium formulations. They leave a white residue.
Concerning the roof moss cleaner: when you add 2-gallons of water to the 1-gallon of 12% sodium hypoclorite isn’t it weaker than using 3-gallons of the 5 to 6% household bleach straight?
Tom Milam
NO, like I say. It’s measured by weight not volume.
I don’t understand “weight not volume”… isn’t 1 gallon SH and 2 gallon H20 both volume measurements? How do we get 1 gallon of weight for SH and 2 gallons of weight for H20? Sorry I just want to make sure I get it right. Thanks!
Weight and volume are two very different things. If you mix it like I show you you’ll have 42k PPM..
Sodium Hypochlorite 14-15% w/w 10 Litre (2x5L) Can I use this stuff I seen on e bay and do I have to dilute it with water an in what amount Thanks R m scotland
Sounds right to me. Can you send me the ebay link to it ?
Link Hidden
Try this ,gives you some options .do I have to dilute the stuff I mentioned as its for moss on roof tiles R m . thanks.
I really can’t say about that product but it does seem to be the right stuff at 14% so yes you would have to dilute a little bit more than shown in this page.
Hello Dominick. Did you get the link to e bay. if not you will find it on e bay under sodium Hypochlorite . I used to work in a carpet factory and we used to get industrial bleach for removing thick dye
from printing screens when washing. This stuff would set fire to cloth in its undiluted state Powerfull How much water do you recommend per ltr for the 14% I bought Thanks for your help Raymond
I didn’t like the feedback from buyers on ebay so I didn’t post the link. 2 gallons of H20 to one gallon of sh.