I am installing a zinc strip on my garage roof to reduce moss growth. I will be sliding the metal between two rows of asphalt shingles and nailing it down, so that the nail heads are underneath the upper row.

What type of sealant should I use on the nail heads? Asphault, silicone, polyurethane, tripolymer?

None of the sealants at my home store specifically mention nails on the label. I live in a climate with cold winters.

  • I dk the answer, but wanted to comment that I tried zinc strips at my house and they really didn't work well. There where installed just under the ridge cap. I think the problem was there wasn't enough zinc exposed to the rain water to get any meaningful amount of zinc oxide down the rest of the roof. My advice and I'm no expert, would be sure to have a fairly wide area exposed to the rain for it to work better. Maybe others could opine on the effectiveness of zinc strips. I live in the NW where we get lots of rain. Jul 3, 2020 at 15:17

1 Answer 1


I have used zinc make sure the strip extends beyond the shingles , we started using wide zinc strips at 2 levels after moving to Oregon and noticing no moss or fungus below the metal roof vents. I like black jack it is a good sealant and if putting a roof I accidentally have a shiner a dab of blackjack on top will seal that exposed nail head. Make sure to slip the zinc under on a warm day so you don’t break the shingles.

  • 2
    I believe the "black jack" product this answer recommends is an asphalt-based roof sealant, and I agree it would be perfect for dabbing over nailheads. Jul 3, 2020 at 19:07
  • Yes it is asphalt based can be purchased in gallons , calk gun tubes, installed dry or wet. I am not sure about freezing but if a hot day +100 it will work then but I don’t work on roofs much any more so there may be a better product out there I have been using blackjack since the 70’s and it has not let me down.
    – Ed Beal
    Jul 4, 2020 at 22:24

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