Install z stop zinc strips 50 foot roll to keep it from growing back.
How to install zinc roof strips.
If possible it is best to slide about 1 4 under the roof ridge vent roof cap or the top row of shingles.
That is you nail down a course of shingles then lay down the new course above the last course working up the roof.
In order to install zinc strips you must either nail them in over the asphalt shingles or break the seal and install them under a strip of shingles.
The premade ones are much quicker and probably neater looking.
You can cut strips of zinc flashing copper and lead work too and slide them under a course of roof shingles to kill lichen and moss growing there or you could just buy these premade strips from shingle shield.
By installing the strips on the ridge any water that runs over them will trickle down the roof carrying the zinc chemicals with it.
Apply z stop zinc strip 50 foot roll by butting it up against the ridge cap against both sides of all roof peaks see graphic.
This way the next course hides the nails holding down the previous one.
Use a hammer and nails to secure the strip to the roof.
Installing zinc strips to prevent moss growth is a leak liability says the asphalt roofing manufacturers association.
Finally the ridge cap goes on.
Rain water must run over z stop to become effective.
Using 2 5 or 3 5 wide zincshield install by butting the zinc strip against the ridge vent roof cap or the top most row of shingles at the roof ridge.
The zinc strip is installed along both sides of the ridge of the roof with most of the strip left exposed.
At the ridge before a ridge cap goes on you also nail down the zinc strips placed so they will protrude beyond the ridge cap.
Continue along the roof until the entire ridge is complete.
Apply z stop below anything that blocks rain water flow such as chimneys gables and skylights.