Gutter & Seam Sealant


  • Permanently Flexible, Water Resisant Seal
  • Seals Most Common Gutter and Downspout Materials
  • Expands and Contracts with Temperature Changes
  • Cures to a Tough Rubbery Gasket


  • 10 fl oz (295 ml)
  • 5 oz (148 ml)


  • White (IDH 1797607, 827681, 1797609, 1460689)
  • Clear (IDH 1460731)
  • Aluminum (IDH 1797596, 827682, 1797611, 1460359)

Clean Up

  • Mineral Spirits

Recommended For

GS121 is designed for sealing around aluminum, galvanized and vinyl gutters and downspouts, sealing seam, joints and cracks in gutter troughs, and for use on sheet metal, air conditioning and heating ducts and ventilators.

For Best Results

Do not tool, feather or smear sealant.   Not recommended for: interior use in occupied structures, as an epansion joint control sealant, or for use on copper.  For joints deeper than 3/8" (9.5 mm), a backing material should be used.


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