Worthington Ohio real estate


A roofing experiment: zinc strips on a roof

I love experiments.   Reuben Saltzman, a Minneapolis MN home inspector is doing "A semi-long term experiment: zinc strips on a moss covered roof"

Have you run into moss on your roof?  I would think it would be more common in MN and cooler northern states in the Great Lakes area  than in Ohio but I have seen it here on homes with a lot of tree cover.  We certainly get enough rain...    Visit home inspectors in the Pacific Northwest's websites if you want to see moss covered roofs.  

I remember moss on an Old Worthington roof, and I have seen moss on the northside of a ColOld Worthington sign with treesonial Hill's roof, so I guess moss happens in Worthington and other Central Ohio communities. 

We do have lots of ugly black algea stained roofs in Central Ohio, a cosmetic issue, according to Reuben.  Reuben's first photo of the black algae stains caught my eye.  I just noticed on a roof in Columbus that the area under metal vent caps did not have the algae stains.

Reuben did a wild and crazy experiment a few years back with ice.... using pantyhose on the roof / gutters.   I think Reuben had another roofing experiment where he ran wires along the gutters... I doubt I Re-Blogged that experiment... too scary, even with "Don't try this at home!" warning.  Thanks to Reuben for allowing this home maintenance experiment post to be Re-Blogged. 

Makes me wonder do roofers use zinc strips on roofs for the ugly black algae in our area?  

While black stains on roofs are a cosmetic issue, moss growth is more than just cosmetic.  Not only does moss look terrible on roofs, it will also shorten the life of the roof covering and possibly lead to roof leaks.  Whether you have wood or asphalt shingles, moss can grow on the roof if it doesn't dry properly.

As with black algae stains, the most common place for moss to grow is on the north side of the roof, but if there are enough overhanging trees or other forms of shade, moss can really grow anywhere.  If you want to kill the moss, follow the link above that explains how to remove black roof stains; the process is the same for killing moss.  The results certainly won't be as immediate, but it's effective.  Today, the focus is on what you can do to prevent moss growth on your roof.

Have you ever noticed that moss and black stains don't appear on roofs underneath the areas with galvanized metal?

Zinc washing off roof vents

The roof stays minty fresh zincy fresh below the vents because every time it rains, a small bit of zinc gets washed off the metal, which runs down the roof and kills whatever is growing on the shingles - whether it's moss, algae, lichens... whatever.  If this is so effective, doesn't it stand to reason that you could install strips of zinc along the top of the roof, and have them protect everything?  Of course.  You can actually buy rolls of zinc made just for this purpose.  The 50' roll of zinc pictured below was about $25 at Home Depot.

Zinc Roll

The zinc is supposed to be installed at the ridges of the roof, or along the hips as needed to make sure that the rainwater washes zinc down the roof.

Zinc Strips Installed

Zinc Strips Installed

I've heard many roofers say that these zinc strips are worthless and ineffective, so I decided to conduct my own semi-long term test.  For my experiment, I installed a zinc strip along the ridge of a moss-covered garage roof approximately sixteen months ago.  I didn't do anything else to this roof - no scrubbing, no chemicals, no nothing.  The before and after photos are shown below, and I think the results are pretty conclusive - zinc strips are effective at killing moss.


Mossy roof before


Mossy roof after

That's a pretty dramatic difference, isn't it?  I cleaned up the roof a bit before taking the second photo by using a leaf blower, but that was all.  Remember, I applied that zinc strip to a roof covered in moss just to see what would happen; zinc strips aren't supposed to be used as a moss remover, they're supposed to be used as a moss preventer.  If you're not in any hurry, they'll apparently remove moss too though.

As they say, individual results may vary.  Zinc strips might not work for every application, but they're not terribly expensive, and they're not difficult for a roofer to install.  If you have an existing roof with a moss problem, try zinc strips.  Copper strips are supposed to work the same way.

Zinc strips are also supposed to be effective at preventing black stains from showing up on the roof.  I'm starting a long-term experiment on my own house; I'll report back with the results in a couple years.

Stay tuned  ;-)


Reuben Saltzman, Structure Tech Home Inspections - Email - Minneapolis Home Inspector



This post provided by Maureen McCabe HER Realtors*

Contact Maureen McCabe of HER Realtors* - 614.388.8249

HER Realtors  Maureen McCabe

Search Columbus mls

email: MaureenatMaureenMcCabe.com  at = @

*Real Living HER

Information is deemed to be accurate but should be verified to your satisfaction.  Information provided herein is supplied by several sources and is subject to change without notice.  Opinions expressed are solely those of Maureen McCabe.



Comment balloon 6 commentsMaureen McCabe • November 08 2011 10:58AM
A roofing experiment: zinc strips on a roof
I love experiments. Reuben Saltzman, a Minneapolis MN home inspector is doing " A semi-long term experiment: zinc strips on a moss covered roof" Have you run into moss on your roof? I would think it would be more common in MN and… more
Everything you always wanted to know about cobwebs
Everything you wanted to know about cobwebs but were afraid to ask was originally published by home inspector Jay Markanich as "cobwebs. " Great time of year for the truth about cobwebs. I did not know a lot of this. I did not know… more
8 Painting Tips to Get You Started!!
Here's some help with the basics on painting from a home stager in New York. Most homes need fresh paint to be competitive in today's real estate market. Thanks to Carmela for sharing this information. Painting, 8 tips to get you… more
Don't Trim Those Toe Nails!
OK… I just could not resist that title. Jay is one of the most entertaining home inspectors on the ActiveRain real estate network. Jay's "Don't Trim Those Toe Nails! " is not about a pedicure… Jay has some valid advice… more
Ice Dams, Pantyhose, Salt
Reuben's 'Ice Dams, Pantyhose, Salt' post makes him sound like a "mad scientist" when it comes to removing ice dams from roofs… the earlier post (link in the second paragraph) has other methods. Don't try these at home in… more
In Worthington… What Do THOSE Blue Signs Mean?
"What do the blue signs mean in Worthington? " It means the owner of the home would like to make a change to the home and there will be a hearing about that change. If you read a sign it tells you exactly what it means. The… more
Fall Maintenance for your Furnace
It's Friday again. That was fast. I am trying to find something about furnaces each Friday. It's Furnace Filter Friday This is a timely Re-Blog of a post from 2 years ago, September 12, 2008. Jim Starwalt a Grayslake Illinois Real… more
It's Furnace Filter Friday…
Change your furnace filter.. it is the first Friday of the month. Last month I declared the first Friday of every month Furnace Filter Friday when I Re-Blogged Jay Markanich a Virginia home inspector's post: Replace Your Air Filter… more
Laminate Flooring. When does it make sense?
Info on flooring from a flooring professional in New York. Laminate has it's place. Thanks to Debbie Gartner for allowing this information to be Re-Blogged. First, let me state for the record I prefer hardwood. … more
NEVER Pressure Wash A Deck!
Home maintenance advice from a home inspector. Jay is in Virginia. I wonder what home inspectors closer to home say? Thanks to Jay Markanich for allowing this information to be Re-Blogged for consumers. I tell my… more