| Author | Message | ||
     Norm Cramer |
I am in the process of selling my home and the buyers want us to remove lichen from the slate roof. This greenish-white rock lichen has been on the roof as long as we have lived here and it never seemed to cause a problem. Should lichen be removed from a slate roof? If so, why and (more importantly) how? I appreicate any information that you can provide! | ||
| Joe Jenkins |
The answer is no. Let the new owners open that Pandora's box. | ||
| Jerry Henger |
Hi Joe, What is the Pandora's box? I know that I read something in your bible about lichen on slate, I went back to refresh my menory and was not able to find it. Here's my sitution. My garage has a slate roof. The east exposure is under a large maple tree and completely shades it. Green lichens or moss has grown on it, almost all of the eastern side, about 70%. Should I do anything? Thanks | ||
| Joe Jenkins |
The lichens and moss don't hurt anything. Removing these things manually can lead to a lot of damage to your roof, mostly by people walking on the roof or power washing, scraping etc. That's why I call it a Pandora's Box - you may end up with more problems than you started with. Copper oxide does kill the lichens and moss. Copper ridge metal may be enough to wash the oxide down your roof and clean it. Otherwise, you can try spraying copper oxide in a water solution periodically on your roof. You can buy the copper at garden supply stores (it's used as an orchard spray and sometimes as an algae killer in ponds). I haven't tried this, but it seems like it should work. I use a copper soap as an orchard spray and it's actually certified organic. | ||
| Rob |
We use copper sulfate to put on the pond to kill algae, but I've never heard of copper oxide. Is copper sulfate safe to spray on a slate roof? Rob | ||
| Joe |
Copper sulphate is essentially the same thing, with sulphur added (also a mold killer). I have never tried either on a slate roof, but would experiment with a small section first and see what happens. | ||
| joe jenkins |
I just noticed that the "Gardens Alive" catalog includes "Moss Aside" which is described as a quick and natural moss killer that is suitable for use on roofs - the active ingredient being a soap-based herbicide. http://www.gardensalive.com | ||
| Shawn Smith |
The problem with leaving the moss on the roof is that it can cause leaks. The moss may not damage the roof itself but moss does block the waters ability to run off of the roof the way that it should. Especially when there is a valley on the roof, moss can build up there (and may help capture even more debris), this is a very frequent cause of leaks in roofs. If you don't have the moss cleaned off (which can be done safely by a professional) at least make sure that it is controlled and not allowed to get worse. I have found the moss killers recommended above to be effective as well. http://www.practicalpressure.com |
