FlintSeal is an all-weather asphaltic-based plastic cement that is engineered to patch splits, seams, and cracks in roof surfaces such as mineral surfaced cap sheet, smooth surface asphalt roofs, composition shingle, metal roofs, and spudded gravel. 

FlintSeal can also be used for repairing areas around chimneys, skylights, vent pipes, gravel guards, down spouts, splits in concrete, and expansion joints on roofs. FlintSeal will not sag, slip, or mud crack, and remains highly resilient and durable throughout all seasons. It is comprised of a homogeneous blend of high­grade fibers, select asphalt, minerals, plasticizers, and aromatic hydrocarbons. 

FlintSeal meets ASTM D 4586 and ASTM D 3409. 

Technical Information

  • Color – Black
  • Consistency – Thick-Soft Mastic
  • Weight - 8.7 lbs. per gallon
  • Packaging – 3G, 5G
  • Coverage – Approximately 12-13 sq.ft. per gallon applied 1/8” thick; additional material may be required when 3-coursing to wet out and encapsulate fiberglass fabric
  • Flash point (T.C.C.) - 105°F
  • Maximum VOC - 250 G/L
  • Service Temperature - 40°F - 90°F


Precautions: For best results in cold weather, store at room temperature for 24 hours prior to application. DO NOT THIN.

1. All surfaces must be clean and free of surface rust and any other foreign matter. Remove rust with a wire brush.

2. Apply by trowel, putty knife or gloved hand at rate of 1/8” – ¼” thick.  Work cement into break or crack extending 2”–4” beyond the problem area with feathered edges.

3. If the problem area is over ¼” wide or 2” long, embed asphalt-saturated or open weave fiberglass fabric to reinforce cement, then cover with additional mastic at prescribed thickness.  

5. Clean tools with mineral spirits or paint thinner.

Warranty Details

CertainTeed offers a FlintSeal Limited Warranty on Materials.

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