Hand Sealing Shingles

Most asphalt shingles have a factory-applied sealant strip that softens in the sun and bonds each course to the one below, which is essential to wind resistance. Hand sealing (or hand-tabbing) means applying asphalt roofing cement or a compatible adhesive by hand to bond shingles where the factory strip will not do the job.

When it is used

• Cold weather. When temperatures are too low for the sealant to activate soon after installation.
• Steep slopes and mansards. One manufacturer requires steep-slope application, defined as 21 in per foot (about 60 degrees) or more, to use six nails and three 1 in (25 mm) diameter spots of cement per shingle, about 2 in (50 mm) above the bottom edge.
• Starter courses without factory sealant, where Canadian guidance calls for hand-tabbing the first course to the starter.
• Valleys, rakes and cut edges, where shingles are trimmed and the sealant line is lost.
• High-wind programmes, which may require cement along eaves, rakes, hips and ridges.

Method

1. Use the material the shingle manufacturer specifies, typically asphalt plastic cement meeting ASTM D4586 or an SBS-modified mastic.
2. Apply small dabs: one under each tab of 3-tab shingles, or several evenly spaced dabs along the lower edge of laminated shingles.
3. Press the shingle into the cement.

Cautions

Manufacturers warn against using too much cement. Excess cement can cause blistering of the shingle. Cement should not be smeared across the surface or left exposed. Hand sealing does not replace correct nailing; it supplements it.