40 years of roofing and observing roofs with moss and algae has caused us to wonder how to stop the moss and algae from growing. If you have a new roof it will take about 7 years for the moss to start growing (depending on your area).
What works and what dosen’t.
We don’t know who first thought about it, or who first tried it, but somebody put a strip of zinc metal on the top of the roof just under the ridge caps to prevent moss from growing on their roof.
In reflection, when observing a moss covered roof, you may notice that there is little to no moss growing on the roof below an area where there is a plumbing stack (Pipe) protruding through the roof.
There is a relatively large lead or zinc flashing around the pipe, and because the pipes are quite low on the roof there is a large volume of water flowing over the zinc. Therefore, leaching out enough chemical to prevent the moss from growing below the metal flashing.
However, when a strip of zinc metal is put at the peak of the roof, it dosen’t get enough VOLUME of water flowing over it to be effective, except for 3 or 4 feet down from the top.
The best tip given years ago to control moss and algae growth was to sprinkle powdered laundry detergent (any brand) over the roof when you know it will be dry for a least a couple of days (make it look as though it snowed lightly) then let the rain wash it away. The results were impressive.
There are also commercial de-moss products at the hardware stores for spraying on your roof.
The commercial product we like is “Spray and Forget”
What can we do about woodpeckers making holes in our roof or siding?
The CSSB suggests that you install hawk/owl statues or silhouettes around your house to scare them off. Woodpeckers do not like the smell of mothballs, and placing these on or around the structure may also assist you.Do you have any suggestions on what to do about wasps nesting under my cedar shakes? Check with your local exterminator for more information.
Are squirrels attracted to cedar roofs?
The CSSB is not aware of a particular tendancy for squirrels to be attracted to cedar roofs. If squirrels are causing a problem, contact your local exterminator for more data.