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R-49 is the common target for the roof or ceiling in cold and mixed climates. That is about 20 inches of blown fibreglass, 15 inches of blown cellulose, 16 inches of fibreglass batt or about 8 inches of closed-cell spray foam. Air seal the ceiling plane before adding any of it.
A tube of caulk goes a long way on a thin bead and disappears fast in a wide gap. Enter how many feet you are sealing, the width and depth of the joint (or pick a corner bead), and the tube size to see how many tubes to buy and how far each one runs.
With these inputs:
| Result | Value |
|---|---|
| Tubes to buy | 5 × 10.1 fl oz |
| Each tube runs | 24.3 ft |
| Bead cross-section | 0.0625 sq in |
| Coverage per gallon | 308 lineal ft |
How the numbers work. A 10.1 fluid ounce tube holds 18.2 cubic inches (1 US fl oz = 1.8047 cu in, NIST Handbook 44). A 1/4 × 1/4 inch joint uses 0.0625 square inches of sealant per inch of length, so one tube runs about 24.3 feet. Double the width and the same tube covers half the distance; double both width and depth and it covers a quarter. Sealant makers publish the same arithmetic per gallon: Tremco's estimating chart lists 308 lineal feet per gallon for a 1/4 × 1/4 inch joint, which is exactly 231 cubic inches ÷ 0.0625 ÷ 12. Sizing the joint. For joints of about 1/2 inch and wider, ASTM C1193 guidance is a sealant depth of roughly half the width, and never less than 1/4 inch, set over closed-cell backer rod so the bead bonds to the two sides only. Stuffing a deep gap full of caulk wastes material and makes a joint that tears when the gap moves. Gaps wider than about 1/4 inch around windows and pipes are better filled with low-expansion foam first. Air sealing before insulating. Caulk seals the joints that do not move much: trim to drywall, window and door casings, baseboards, top plates in the attic and plumbing penetrations. Seal these before adding insulation; air carries heat and moisture straight through fiberglass. The dew point calculator shows why moist indoor air leaking into a cold wall is a problem.
Bead area (sq in) = width × depth, or width² ÷ 2 for a triangular corner bead · Volume (cu in) = bead area × length (in) × (1 + waste %) · Tubes = volume ÷ (tube fl oz × 1.8047 cu in per fl oz), rounded up · Lineal ft per gallon = 231 ÷ bead area ÷ 12
| Joint (width × depth) | Ft per tube | Ft per gallon |
|---|---|---|
| 0.125 × 0.125 in | 97.2 | 1,232 |
| 0.25 × 0.25 in | 24.3 | 308 |
| 0.375 × 0.25 in | 16.2 | 205 |
| 0.5 × 0.25 in | 12.2 | 154 |
| 0.75 × 0.375 in | 5.4 | 68 |
| 1 × 0.5 in | 3 | 39 |
Computed with this calculator; the per-gallon column matches Tremco's Joint Sealant Estimating Chart (1/4 × 1/4 in = 308 ft).
A 10.1 fl oz tube covers about 24 feet of a 1/4 × 1/4 inch joint, about 48 feet of a 1/8 × 1/4 inch bead, and about 97 feet of a 1/8 × 1/8 inch bead. Wider or deeper joints use it much faster.
At 1/4 × 1/4 inch, 100 feet is 75 cubic inches, or 83 with 10% waste — 5 tubes of 10.1 fl oz. At 1/8 inch it is 2 tubes.
A standard 60 inch tub against three walls is about 12 feet of corner bead. A 1/4 inch fillet uses 0.03125 sq in per inch, so the job takes about 4.5 cubic inches — well under one 10.1 fl oz tube, or one small squeeze tube.
For joints up to about 1/2 inch, fill the gap; for wider joints aim for a depth about half the width, at least 1/4 inch, over backer rod (ASTM C1193 guidance). Too deep a bead wastes caulk and cracks when the joint moves.
Need the whole roof at once? The free roofing calculator works out roof area, squares, shingle bundles, underlayment, drip edge, ridge cap and installed cost from one set of measurements.