On Aug 30, 10:53*am, Aaron Fude wrote:
Hi,

On the north side of my house I have moss on the slate roof. I'm
concerned that it's pushing the slates apart. My roof is 90 years old.

How do I combat this problem?

Thanks,

Aaron

A zinc strip at the top of roof is common where I live, Laundry bleach
will kill it now but moss grows in debris , is roof covered by a tree
and not steep pitch so it collects dirt. Mold or green coloring is
common and no harm but moss to me means roof doesnt clean itself by
rain, by moss you mean it is maybe 1/2" thick and it pulls up intact?
My slate roof has green mold, but no buildup in thickness. Moss would
be a problem. The only true moss I have or have seen grows on the
ground. Roundup will kill it but take longer and cost more than
bleach.