My roof has some pretty serious mold growing on it. It is a GAF Timberline Ultra (50year) shingle roof that is about 12 years old. The mold is mostly in the shaded areas (duh) and below the doghouses. It is a pretty steep pitch (12-12) so I would rather not walk on it.
When I clean the gutters, from a ladder, I can sort of pick off the mold “blooms” – they are like little plants stuck to the roof. This is not a very efficient method and I was wondering if there is a chemical I can spray over the roof to kill the mold.
I figured bleach would work, but I don’t know the effect it has on the shingles.
On some other small roof projections, like over a bay window, I put a zinc strip under the top course of shingles. This helps right under the strip but only where water runs down over it.
Any thoughts?
Thanks.
Replies
I'd go further with the zinc strip. Just stick some galvanized flashing under the cap shingles, leaving an inch or so exposed.
Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
Someone suggested copper instead of zinc. Does it matter? This may be stupid but, how much zinc is there in the galvanized coating? I know the galvanizing wears out over time. I don't want to have to replace the strips every couple of years since the roof pitch is so steep. I do have a place I can get "pure" zinc strips. They are not cheap but neither is falling off the roof every couple of years.
Thanks.
I'd only fall off once.
No... wait... I'd NOT fall off once.
You hafta clean the gutters anyway, so installing pure zinc in strategic places above the fertile areas shouldn't cost a bunch of time, money or risk. Troy Sprout
"Don't forget the screws"
I don't know how long the galvanization lasts. Too many variables to say. How long do galvanized steel barn roofs last? The pure zinc might be pricey, but what are we talking? A C-note? That would be a no-brainer.
The copper would work, too. You might get some verdegris streaks, though.
Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
Edited 6/2/2006 1:54 pm ET by Andy_Engel
There are companies that clean roofs and they are a little pricey but they usually have a service contract that is a pretty good deal.
ANDYSZ2
I MAY DISAGREE WITH WHAT YOUR SAYING BUT I WILL DEFEND TO THE DEATH YOUR RIGHT TO SAY IT.
Remodeler/Punchout