Moss on roof

[Steveo]

I am starting to get moss growing on my roof. Can anyone tell me how to get rid of it without hurting the roof shingles underneath.

Thanks

[dmjr]

I have heard that if your spray deck wash (diluted down) and then lightly pressure wash it the moss should come off.

[Sunrise Point]

Zinc strips up near the peak (under the cap shingles with a few inches exposed) acts as a great preventative.

This Old House has a little info @ http://www.thisoldhouse.com/toh/asktoh/question/0,,401167,00.html

Whatever you do, be careful if you intend to go up on the roof yourself.

Best wishes

[upthesaukee]

I am having a new roof put on starting tomorrow. Old roof had mega moss, looked like a forest floor.

Roofer said zinc strips would help, rain water hits the zinc, washes down the roof and kills the moss.

Also said my moss was due to moisture (stream right behind house, <10 yards) and trees that overhang or close to overhanging, not letting the sun hit roof and dry out. Same problem in back yard on ground: always damp and moss covered.

I am going to have some trees removed.

I would be careful with any pressure washing. Regular house pressure would probably be best.

[Slickcraft]

I am having a new roof put on starting tomorrow. Old roof had mega moss, looked like a forest floor.

Roofer said zinc strips would help, rain water hits the zinc, washes down the roof and kills the moss.

Most new shingles have "algae-inhibiting granules" to prevent growth, see:
http://www.iko.com/shared/residential/techdata/4220XXXCambridge30AR-EngFr.pdf

They are granules of either copper or zinc; make sure the new shingles are so treated.

[Steveo]

[QUOTE=Sunrise Point;91556]Zinc strips up near the peak (under the cap shingles with a few inches exposed) acts as a great preventative.

This Old House has a little info @ http://www.thisoldhouse.com/toh/asktoh/question/0,,401167,00.html


Thank you Sunrise.

I think the zinc will help with prevention (thx - upthesaukee), but I am worried about what they (This Old House) says about removal of the existing moss. They say to scrap (ouch), that sounds damaging to the roof shingles. What is the best way to remove the "built up" moss, without destroying existing shingles.

Then, what I am getting from your comments are install the zinc to keep both the "black stains" and the eventual moss buildup from occuring. Am I getting this right.

Sorry to be so dense

[dpg]

[QUOTE=Sunrise Point;91556]Zinc strips up near the peak (under the cap shingles with a few inches exposed) acts as a great preventative.

This Old House has a little info @ http://www.thisoldhouse.com/toh/asktoh/question/0,,401167,00.html


Thank you Sunrise.

I think the zinc will help with prevention (thx - upthesaukee), but I am worried about what they (This Old House) says about removal of the existing moss. They say to scrap (ouch), that sounds damaging to the roof shingles. What is the best way to remove the "built up" moss, without destroying existing shingles.

Then, what I am getting from your comments are install the zinc to keep both the "black stains" and the eventual moss buildup from occuring. Am I getting this right.

Sorry to be so dense

Your correct. I happened to watch that episode on T.V. when it was on. Tom Silva installed the strips that they explain. That's the comment about the flashing around the chimney and how below it you will usually not see any staining. Lightly scrubbing shingles to remove moss will not harm them. A little common sense needs to be used as to how aggressive to be with them. On the show he sprayed the moss with the water mix removed the moss and installed the strips.

[tis]

I am told you can pressure wash the roof lightly and then apply the zinc strips. Trees close to the house DO do a lot of damage.

[dpg]

I've pressure washed our roof in NH before for the same reason - moss. Obviously just don't go real crazy with the pressure, the shingles take a lot more abuse than you may think.

[TomC]

I think it looks sort of "cottage-y". So is there any reason to remove it other than esthetics? Does it degrade the roofing material or cause water to back up or anything?

[SIKSUKR]

I'm sure that anything that keeps your roof wet or moist might eventually want to migrate to the sheathing under the shingles.Of course most roof systems have a vapor barrior but every nail hole is a potential moisture wick.I would definately not want moss on my shingles.

[RLW]

I'm sure that anything that keeps your roof wet or moist might eventually want to migrate to the sheathing under the shingles.Of course most roof systems have a vapor barrior but every nole hole is a potential moisture wick.I would definately not want moss on my shingles.

Now I see how you get the number of your posts to go up. You post them twice in a row. :laugh::laugh:

[Lake Shore CT]

Another way to kill moss on a roof is to put rock salt on the moss and let it sit. It will start to kill the moss off an then you can remove it after it dies pretty easily. Be careful with the rock salt that it does not get on concrete walks/drives, etc. so it does not eat the concrete. I would not suggest a pressure washer as you can do more damage if you are not careful.

[gravy boat]

Since I replaced my old shingled roof with a metal roof I haven't seen a lick of moss. :look:

Snow, however, tends to build up as it slides off. And we won't soon forget how, last year, a particularly large build up of snow and ice blew out part of our deck railing last year.

<sigh>

Tradeoff, I guess.

[dpg]

Yes...Moss will degrade roof shingles in time. They tend to bond themselves to the shingle (for lack of a better word.) They hold a lot of moisture when wet.

[Happy Gourmand]

I heard somewhere that a mixture of water and household bleach will take care of the problem.

[SAMIAM]

I just got up there with a stiff brush and it rolled right off without any damage to the shingles.

[jmen24]

Pressure wash from the top down with a mixture of Simple Green (Non-toxic) and Water. Always pressure wash roofs from the top down. If you are concerned about doing this, hire someone that does this all the time, painters are a good place to start. I would refrain from using a brush with anything more than a medium brisle and at that rate you are not removing much. You will remove some of the particles from the shingles and you will void the warranty on your roofing product, remember most roofs come with a 30 year warranty.

Rock salt will also kill everything under your eaves so I would refrain from using.

Apply the zinc strips after your roof is clean, the strips need to be nailed off under the top coarse of shingles as to protect against leaking, do not just nail them on.

The flashing around chimneys is lead and that is why you will not see mold below chimneys.

[ArborTech]

Many times if you have moss on your roof, it is in fact due to shaded and damp conditions. If your house is bordered by Red Oaks in particular, but any hardwood for that matter, they are most likely the cause. PM me if you'd like to talk about some solutions for the trees with or without taking them down.

[dpg]

Actually I took a little off of my roof in Mass last fall. The roof is app. 6-8 yrs old and sees roughly 2-4 (more towards 2) hours of sunlight a day. What gives, isn't that enough sun? It's not directly under any trees some beside it though.

[Hippie Girl]

I heard this, www.wetandforget.com/products_wetforget.php
advertise on the garden show on the radio.
Have not tried it, but have seen it in most garden shops.

HG

[fatlazyless]

Bleach will kill moss and mildew so a mixture of water and bleach sprayed on w/ a one gal garden sprayer will slowly erase the moss. For thick moss a plastic garden rake works.

It's no secret that this summer has been a good one for the mold, mildew and moss to grow fast. Definately, a moldy summer!

[Rattlesnake Guy]

Probably repeating here.
Galvanized steel or copper above the area will cause rain to kill or prevent. We use copper pipes at work to keep black algae from growing in the strong acid tanks. (Put loose scrap pipes in the tank) Observed a wood shake roof with a 2 inch exposed copper strip showing under every 10th row. My next roof will have one at the peak under the capping shingles.

[Misakame]

I found some zinc powder in one of the big box stores that you either sprinkle on or make into a water solution and spray on. Very effective and will not harm the roofs. The moss will wash off in a heavy rain - just don't forget to clean out the gutters!!

[Rattlesnake Guy]

I found some zinc powder in one of the big box stores that you either sprinkle on or make into a water solution and spray on. Very effective and will not harm the roofs. The moss will wash off in a heavy rain - just don't forget to clean out the gutters!!

Misakame,
Do you know if it works on the dreaded black mold on the south facing asphalt shingle roof?

[Marker42]

I'm a contractor by trade and a mainland and island homeowner owner and see it all. Here's the scoop! Take a low powered pressure washer with the pin point rotating nozzle and lightly pressure wash the shingles by first wetting the moss and then at a very slight upward angle wash the moss off. This will get the moss at the very edge end of the shingle clean and then wash the mess down off the roof. While washing the roof pay close attention to possible soft spots and issues that there could be in the roof. If you you find a lot of issues it's time for a roof. Next if possible get rid of any overhanging trees and let the sun in! If you want to prevent lichins and moss in the furture have the copper or composite strips installed. If you have mold on good thing to use is Jomax and bleach. Mix as directed and spray on, let set and wash off. This works most of the time. Tom