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Rolls of joist, beam and rim tape for a deck frame, from the deck size and joist spacing.
With these inputs:
| Result | Value |
|---|---|
| Joist tape (1-5/8 in × 50 ft) | 4 rolls |
| Joist + band linear feet | 172 ft |
| Beam tape (3-1/8 in × 50 ft) | 1 roll · 16 ft |
| Rim tape for the ledger (11 in × 50 ft) | 1 roll · 16 ft |
| Joists counted | 13 |
| Joists | ceil(16 × 12 ÷ 16) + 1 = 13 |
| Joist tape | 13 × 12 ft + 16 ft band = 172 ft |
| Rolls | 172 ft × 1.1 ÷ 50 ft |
Roll sizes are Trex Protect's: Joist Tape 1-5/8 in × 50 ft, Beam Tape 3-1/8 in × 50 ft, Rim Tape 11 in × 50 ft (25 ft rolls also sold). Other brands sell different lengths — change the waste allowance or divide the linear feet by your roll length. Doubled joists and stair stringers need extra.
Butyl joist tape covers the tops of joists, beams and the ledger so water can't sit in screw holes and checks in the wood. Enter the deck length along the house, how far the joists run out, the joist spacing and the number of beams. The calculator counts the joists, adds up the linear feet of narrow joist tape, wide beam tape and optional rim tape for the ledger, and turns each into 50 ft rolls.
Add up the length of every joist, the band joist and any beams. A 16 × 12 ft deck with joists 16 in on center has 13 joists: 13 × 12 = 156 ft, plus 16 ft of band = 172 ft. With 10% for overlaps that is 189 ft, or four 50 ft rolls of joist tape.
Narrow tape for single joists and wide tape for doubled joists and beams. Trex Protect, for example, sells 1-5/8 in joist tape, 3-1/8 in beam tape and 11 in rim tape for ledgers and rim joists.
Building codes don't require it, but it keeps water off the top of the joists where deck screws go in and where checks open up — the part of the frame that rots first. It costs little next to replacing a frame under composite boards meant to last decades.
Yes. Beams carry the joists and collect water at every joist crossing, so they get the wider beam tape. Trex lists joists, rim joists, beams, stair stringers, blocking and the ledger as places for its tape.
Trex Protect joist, beam and rim tapes come in 50 ft rolls (rim tape also in 25 ft). Check the label of the brand you buy and divide the linear feet by its roll length.
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