Do I need joist hangers on all joists?

Joist hangers are required wherever joists frame into a beam or header rather than resting on top of a bearing surface. For joists that rest on a sill plate, they are optional but recommended.

What nails do I use for joist hangers?

Use 1.5" x 10d joist hanger nails (often called hanger nails or LULs). Do not use regular 16d sinkers — they are too large for the nail holes.

Joist Hanger Calculator

Calculate the exact number of joist hangers needed for your floor or roof framing.

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Enter Your Measurements

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How to Use This Calculator

1Enter the total number of joists or rafters that need hangers.
2Click Calculate.

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About This Material

Joist hangers (Simpson LUS or LB series) are galvanized metal connectors that support joist ends at beams and headers. Required where joists cannot rest on a ledger or plate.

Installation Tips

•Use all the nail holes — every nail matters for rated load capacity.
•Use joist hanger nails (1.5" x 10d) — do NOT use regular 16d nails.
•Check the hanger is specified for your joist size.

Common Mistakes to Avoid

Under-nailing hangers — partial nailing dramatically reduces capacity.
Using the wrong size hanger for the joist.
Using plain-shank nails instead of specified joist hanger nails.