In the past I’ve read many comments about cleaning the junk that grows on a north facing roof, but never bothered to save the info. I wish I had because I need to clean mine. Now, after searching for some info…I have yet to find an answer to my question.
My plan is to use a 50-50 mix of bleach and H20 and starting from the bottom, work my way to the peak. How long do I leave it before rinsing, or should I just leave it for mother nature to rinse off with the next rain?
I’ve use that mixture for cleaning the concrete for the front sidewalk, steps and porch deck and just left it without any problems. A few days later I rinsed it off with a garden hose and it worked like a charm too. But as for asphalt shingles…I’m clueless
Replies
You don't need to rinse. in fact, you don't want to.
Be sure to soak it well, a light misting won't do it.
Some green moss and lichen turns an iridescent green for a week or so, but the color recedes over time.
Fighting Ignorance since 1967
It's taking way longer than we thought
I have the same issue with the north side of my roof. It is black color, Timberline Arch., 50year shingles. Will the bleach harm or discolor the shingles if I let it dry? How long should it remain on the roof - I mean should I apply it only if no rain is forecast for a few days or is 1 day without rinsing enough? Is 50/50 the ideal mix or is stronger better? I would prefer to kill it all in 1 shot without having to repeat or even worse to scrub the roof.
Thanks.
Bleach doesn't seem to affect the shingles, and I've talked aboiut this with a materials rep for Ownings Corning.The amount and number of applications will vary depending on the condition of the roof.I usually see 50/50 as the recommended concentration; although I wonder if it needs to be that high. (For example, it only takes a couple of drops in a gallon of flood water with possible sewage contamination to make it "fit" to drink.)BTW, I've also had success with some of the vegetaion killers sprayed on.
Fighting Ignorance since 1967
It's taking way longer than we thought
> .... it only takes a couple of drops in a gallon of flood water with possible sewage contamination to make it "fit" to drink.)
For emergency drinking water, you're trying to split the difference between killing the bugs and not killing you. Single cells are a lot easier to kill than larger lichens and moss.
-- J.S.
Just asking...
Fighting Ignorance since 1967
It's taking way longer than we thought
BTW, I've also had success with some of the vegetaion killers sprayed on
I hadnt thought of that. Will try it this weekend. Desperate.
Good deal...thanks! Not having to worry about rinsing is even better.
As for the vegitation killer, any specific brands? Everything worth using around here (New England) has been taken off the market. I used to be able to treat my driveway one time and be done for the season. Now it takes several applications and I still have crap growing back.
>>any specific brands?I'm not sure, I just go to my local farm supply store and ask for whatever the local farmers are using to kill the weeds around their fields and fences <G>
Fighting Ignorance since 1967
It's taking way longer than we thought
"ask for whatever the local farmers are using"
Hmm...might look a little funny with a bunch of cows and goats on my roof. ;)
I'd love to know what my state DOT uses. Last time the DOT's boom mower made the rounds on the road I live off of, they sprayed something around all the guard rails. Everything pretty much turned to dust. I'm talking 3' growth...next day it was all history. It must not be that toxic either, because they even did a 200' section that borders protected wetlands.
Hmm...might look a little funny with a bunch of cows and goats on my roof. ;)
Guess ya missed the roof top Bordello...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!<!----><!---->
Forget the primal scream, just ROAR!!!
treated shingles only kill the algae for about 8 years.many receipes on the web
most are water tri sodium phosphate (TSP) and water. takes several applications on asphault shingles.
>>>>>>>>>>treated shingles only kill the algae for about 8 years.Where do you get your info?
"Let's go to Memphis in the meantime, baby" - John Hiatt.
http://grantlogan.net/
You do asphalt roofs too, right?...what's your experience with the treated ones?
They've only been selling them here for about 12-15 years and and they started with select brands and models. Now, most all shingles sold here are algae resistant. The algae resistance consists of copper granuals mixed in with the surface aggregate. Theoretically, as long as there's still granuals on the face of the shingles they should still work. It doesn't take much to resist algae. Now, Last week I was bidding a roof next door to one I did with AR shingles at least 12 years ago. The roof we tore off was moss covered slate (which had destroyed the slate). I didn't notice any signs of moss growing on the "new" roof.
"Let's go to Memphis in the meantime, baby" - John Hiatt.
http://grantlogan.net/
Cool...thanx
Moss is that nasty? Never knew it would destroy slate. I thought that stuff was forever.
It holds moisture and the damage is created by the freeze/thaw cycle. Nothing's forever.
"Let's go to Memphis in the meantime, baby" - John Hiatt.
http://grantlogan.net/
After I posted, I realized that might be the case.
If one word could describe my opinion of the results, it would be...NICE!!
I'm impressed big time! Within a few minutes of spraying, the first thing I noticed was the greenish/brown haze lifting. Then after I finished, the junk that looked like bird turd started to wrinkle and lift. Had to fight the urge to rinse it with a hose. I'll heed the advice and leave it alone.
I realize it depends on several things, but any idea how long it takes before this stuff disappears completely, if it actually does? The pics I attached give you an idea of what I was dealing with.
Oh yeah...what's with the black streaks, will they disappear too? Is that what lichen is or is it the bird turd looking junk?
Thanks for the pix.
I have been following this thread closely since I thought is sounded like what was on my roof.
Tha looks like my roof except mine is a 12/12 pitch so there is now way I am climbing on it.
Those "alien" looking growths are all over the north facing side.
Please send some "after" photos.
Thanks.
The only reason I went up on mine to do it was because I had "easy access". Having to make several trips up and down to refill the sprayer tank is something I'd rather not do by ladder. Had to hustle 'double time' too, because the wind was speeding up the evaporation rate.
The spots appear to be lichen, which is an algae-moss combo. The bleach will zap the algae quickly, but it takes a bigger dose to "denature" the moss. However, with the algae killed the lichen will presumably die and slowly fade, even if you don't get the moss part.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
OK...got it now and it makes sense.
Thanx
Now for a few after shots. I'm no photographer, so excuse the quality. I only did the garage and porch roofs yesterday. The winds picked up after I did those 2 and it was a little too nasty for my azz to be dancin around 30' up on the second story roof. Probably be a little difficult to try and spray in 20-30 mph winds too. Plus I'm home alone again...my DW and daughter are gone for the weekend and I'd hate for them to find me laying on the ground when they come home tonite.<g> Don't worry...I got hammered enough in the past about my safety practices, so I tied myself off to the pump jacks out back and ran the rope over the peak. So if I do fall(sheet...I sure hope I don't), they'll just find me hanging instead<BG>
As soon as I finish with this post, I'm outta here. No wind right now, so I want to take advantage of it. I'll get more pics too.
Last nite it rained. Nothing heavy, but a moderate blast that lasted for about 20 mins or so. Should I bother to give the lower roofs a second shot? No rain is expected for the next 5 days or so, if it matters.
Sorry about the double of #2...how do I remove it? Flaming ISP BS!! Is there a way to edit/delete your attachments?
Edited 9/10/2006 9:53 pm ET by caveman
do
>edit>manage attachements button
>select which to delete
>hit deleete button
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
ahha...thank you my good man
Duh!!... guess I never thought to look there. Looked everywhere else though<g>
Well, I did it and I didn't fall off either...or I should say BLOWN OFF!! No sooner than after I finished spraying the first batch, the wind picks up again. Jeez...gimme a break Mother Nature!! Why me??? Why right now?? It never fails...but I stuck with it and got it done. It freaked me out a little at first, but I kept drilling it into my head over and over..."don't freak out and you'll be fine"...and it helped. At least I got a few courses down by the eaves done before it got windy. Damn, I can still feel the uplift as I'm typing this...WOW...what a rush!!
Anyway...here a few before pix. It didn't look as bad from the ground, but up here in person it was fugly.
Here's an interesting comparison of before and after. The afterLUNCH looks like someone lost their lunch...literally
This is definately proof that the bleach mix works...IMO anyways
Here's a few taken while I was spraying. But after the winds started, I had to leave the camera on the pump jacks out back. I didn't want to ruin the camera with all the overspray blowing back at me. In fact the Tshirt I was wearing now has a kazillion little bleach spots on it, so I can just imagine what it would have done to the camera.
The shirt also made for an interesting conversation with my DW when she got home tonight. At first I don't think she believed me..."You went up on that roof and no one else was home? Your nuts!!" Yep...that I am, but it needed to be done. I tried to explain to her why I was doing it, but I gave up. She wasn't about to buy it. She probably figured it was just another one of my brainstorms that I learned from a bunch of guys on the internet...and believe me, you don't know how many times I've heard that line before!
-sprayingH2- shows the immediate results after spraying
After it was all sprayed...
no sense in posting afterH3LUNCH again, it's a couple posts back
Algae is relatively harmless (if unsightly), but moss will destroy a roof. It's "role in life" is to grow on rocks, get its roots down into the tiny cracks, and break them apart. It'll do this on slate, wood, or asphalt. Generally it can only get started on asphalt once the surface has started to degrade and crack, though a lot depends on exposure, leaf fall, etc.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
On the upper roof, I did notice a few klinker balls of what appeared to be moss at the bottom edge of a few shingles. If it was moss, I wonder why it grew? No leaf problems at all, just northern exposure and the roof is only 13yrs old.
Really?
ROTFLMAO...
Nope, seen it!
hey...aren't you up a little early? or is it...stayed up late?
must be nice to be retired
;)
usual hours...
quit coffee... got things ALL THROWN OUT OF WACK...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!<!----><!---->
Forget the primal scream, just ROAR!!!
say WHAT???
ya gave it up? WTF...health issues I imagine?
I live for that black crud in cold weather. Where you live, I'd be drinking it year round.
You axe the smoke stack too?
yup...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!<!----><!---->
Forget the primal scream, just ROAR!!!
Damn...
No, make that DOUBLE DAMN!!
Good for you. Now I understand why your still(?) up.
I wish I had it in me to do the same...
You can buy copper sulfate used to control weeds in farm ponds. It's less hazardous than most other herbicides.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
you know i just seen on this old house where tom silva installed some zinc type flashing under the ridge caps. apparently the rain will flow off this and the residual zinc will inhibit lichen/mold growth. for the existing mold/lichen growth he used a 50/50 ratio of bleach to water (I think) and I think just left it on until the rain washed it off
Both zinc and copper (sulphates) will do that, but they tend to work unevenly, with less effect the further down you go.I posted a pic here a few years ago of a local church with "streaky moss control" from copper flashing (couldn't find it in a search, though)Another pic I posted shows the basic effect - it's attached to http://forums.taunton.com/tp-breaktime/messages?msg=51769.1
Fighting Ignorance since 1967
It's taking way longer than we thought
this old house where tom silva installed some zinc type flashing under the ridge caps.
Local roofing supplier sells what he calls "zinc strips" designed for this purpose. I think it was about $1 per lineal foot, but i may be wrong. That seems awfully expensive for some zinc coated steel.
I have the most hope in this solution, just don't feel like doing the installation on a roof that was shingled 10+ years ago.
I remember that photo that rjw mentioned, the preventative effect of the metalic action was incredible.
Look at any house with a bad algae problem (white roof with black stains) and notice the areas around flashings, TV antennas, etc, where the copper or zinc has had an effect. Generally the area will be algae-free in an area running down the roof from the metal.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Look at any house with a bad algae problem ... and notice the areas around flashings, TV antennas, etc, where the copper or zinc has had an effect. Generally the area will be algae-free in an area running down the roof from the metal.
That is exactly what I've observed on my own house, with the source of zinc being a simple antenna mast. That is why if I can't kill the moss this time I'll take off a line or two of shingles at the ridge and install those zinc strips.
You don't have to pull shingles off. The strips can just be tacked under the ridge shingles, protruding 2-3 inches.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Thanks...I've heard about using that, I'm just not sure if I'd want to retrofit that stuff to my existing roof.
From what I understand, I think the best route would be to use the treated roof shingles. Next roof replacement I do in about 4-5 yrs will probably be those.
I understand that there's also a moss and algae killer out there tha't manufactured specifically for that vegatation. Check with a good garden supply store. (It's probably a 50-50 mixture of bleach and water with some coloring and perfume thrown in. LOL)
Don K.
EJG Homes Renovations - New construction - Rentals
Channel #5 or Poison?
;)
Bleach is fine, but you don't want a general purpose vegetation killer because the residue that rinses off the roof will harm your landscape.
After cleaning, you should prevent regrowth so you don't have to keep doing it over and over. Zinc and copper strips are the standard effective method. As they oxidize and run down the roof the oxides will prevent regrowth safely. The strips are available on the internet. Try searching for algae control roof or something like that.
I haven't had any problems - controlled application I guess
Fighting Ignorance since 1967
It's taking way longer than we thought
Good point about general veg killers. Didn't think about that...oops<g> I've also heard that some of those products can cause staining.
So why doesn't the bleach mixture cause any harm to the landscape, yet it kills the junk that grows on the roof?
I'm only guessing here, but I imagine that algae is more sensitive to chlorine than higher plants and the algae is soaking in it, whereas general landscaping is only splashed with it.
Bleach WILL cause harm to vegetation. Tie a plastic bag to each downspout or otherwise control the runnoff.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
You consider fescue grass vegetation? I would think it is and yet it didn't bother it at all when I did the concrete sidewalk. In fact I'd swear it acted like a fertilizer...?
There is one downspout exit that handles the front roofs and it drains out into the gravel driveway, so no harm done there. I did remove the few potted plants my DW had on the porch, so nothing else to worry about.
I wonder if this mix would work for weed control in my driveway? It didn't do jack to the fescue, so I have my doubts. But it sure would be cheaper than what I've been using.
I am assuming you have already washed the roof so this may be moot. But bleach is very corrosive. A 50/50 mix in my opinion is way too high. Damage to any painted surfaces and plants in landscaping will take a hit. Paint will chaulk. Therefore you would need to rinse very very well anything else that the 50/50 mix hit.
When I used to power wash as a business I used three gallons of bleach in a 55 gallon drum of water as a mixture. I also added half a bottle of dish soap to aid in keeping the mixture on the surfaces that I was washing. The lemon type smells good too. Start from the bottom and ascend up the work surface to prevent streaking. I would soak all affected areas then return to the beginning and start rinsing. Depending on the job, soak time might be around an hour. This time, rinse from the top down. A 1200-1500 psi machine with a 15 degree tip should be adequate to complete a job such as yours. Anything larger in psi might blow your shingle grit away. Just adjust your distance of the wand from the work surface.
In my experience for what it is worth have had no help spraying moss and heavy plant life on structure with using bleach. In this case I relied more on plain water going through a power washer, for porous surfaces like brick and concrete. We wash on an average of twice a year here in the south to keep everything up to par and don't get a great build up of green stuff if maintained in this fashion.
Semper Fi
Yeah, the dish soap is a good idea -- serves as a "wetting agent", to help the solution cover the surface and stick to it.If you wanna get fancy there are commercial wetting agents (forget the names), but the dish soap is probably good enough.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Too late to weaken the mix any...I did it all with the 50/50 mixture and no damage noticed other than some discoloring of the lead flashing for the chimney. I'm currently replacing the siding, so it didn't matter if it stained or whatever either. I also didn't pre-wet it, but now that you mention it I wish I did add some dish soap. that might have slowed down the evaporation rate due to the winds. It was tough trying to keep a wet edge since I was only working wiith a 2 1/4 gallon sprayer and had to refill quite often. Next time I'll add the soap. Thanx
What's the 15* tip, a wide fan spray? I used my pressure washer on the porch a few yrs ago and kept the tip about a foot or so away from the shingles, but after hearing it's not advisable...removes the granules...I'd wanted to try something else. The pressure washer did one he11 of a job though, even with just plain cold water.
What's the 15* tip, a wide fan spray?
Yes you are right, less intrusive. A 0-degree tip is like a pin hole shooting water straight, a lot of pressure in a concentrated area.
Semper Fi
> So why doesn't the bleach mixture cause any harm to the landscape, yet it kills the junk that grows on the roof?
The chlorine compound in bleach decomposes quickly. If you don't get overspray on plants you want to keep, and don't use so much that it runs down the downspout, it'll be gone in a day or so. If it starts to rain while you're spraying, that might carry some of it onto things you don't want to kill. Rain a couple days later won't have any chlorine left to carry down.
-- J.S.
Chlorine bleach is a pretty potent "denaturing" agent -- it attacks proteins and other organic chemicals and changes their chemical composition. It can also upset the balance of electrolytes in the plant cells, causing cell death. It does dissipate fairly rapidly, though, especially when mixed with soil.MOST typical lawns and house plantings won't be harmed by small amounts of it (aside from possible spotting where it splashes), but large amounts (enough to soak the ground or thoroughly wet the plant) will certainly kill just about anything, and some plants may be particularly sensitive to smaller amounts.When it comes to the DW's plants, better safe than sorry.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
"but large amounts (enough to soak the ground or thoroughly wet the plant) will certainly kill just about anything"
If that's the case, then next year I might try using it for weed control for the driveway. Can't be any worse than what I've been using, and it's cheaper.
btw...do you know of any concerns about when it(the bleach mix) contacts lead? Today I noticed the lead flashing for the chimney has a light rust looking appearance. Sure hope I didn't cause any significant damage. If it did, I could always replace it, but I sure as heck don't need any more work to do right now
Edited 9/11/2006 10:53 pm ET by caveman
I doubt that the bleach would seriously damage the lead. Probably just took the patina off.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
cool...I was a little concerned when I first saw it
My plan is to use a 50-50 mix of bleach and H20
That approach had no effect on my roof moss.
>>That approach had no effect on my roof moss.Did you soak it well?
Fighting Ignorance since 1967
It's taking way longer than we thought
Did you soak it well?
I don't remember. I'll assume I didn't and try it again. This weekend. But won't it just "dry" with evaporation? Keep re-applying it to keep it soaked? Put a wet blanket over it to keep it wet an extra hour? Any ideas would be appreciated.
Last time ( acouple summers ago) I finally just physically removed it. Using a hose and my household water pressure. It took hours to do a small area. That's why I want a different method this time.
When I did the concrete with that mix, it didn't evaporate. In fact it was damp for quite awhile...at least a day or 2 anyway. Also considering that the problem areas are North facing, I don't think evaporation from direct sunlight shouldn't be of any concern either. Fall is almost here and cooler weather will make this a good time of year to do it. I agree with rjw...you need to soak it for it to work.
I'm off to get some bleach shortly so I can hit it today. Seems this topic might be worth taking some pics, so I'll take some before, during and after shots if there's any interest.
Bleach will almost instantly clear up algae, but has only modest a effect on moss.Of course, keep in mind that moss can generally only get started when the roof is fairly far gone to begin with.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Reading your earlier post and now I realize that I had better distinguish between algae and moss. It's moss that's troubling mine. Much more of a problem I read than the simpler algae.
Zinc/copper will help control moss too, but not as well as it controls algae.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison