Timber / Lumber Fastener Spacing Calculator

Calculate the number and spacing of nails, screws, or bolts needed for timber and lumber connections.

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How to Use This Calculator

How to Use

  1. Select your unit system (Imperial or Metric).
  2. Enter the timber member length (and width for perimeter fastening).
  3. Choose the fastener type — nails, screws, or bolts.
  4. Choose the connection type — single row, double row (staggered), or perimeter (for sheet goods).
  5. Optionally set custom spacing, edge distance, and end distance. Sensible defaults are provided.
  6. Adjust waste percentage if needed.

Spacing Guidelines

  • Nails: Typical spacing 6" (150 mm) on center for framing connections.
  • Screws: Typical spacing 8" (200 mm) on center for structural connections.
  • Bolts: Minimum spacing often 4× bolt diameter; typical 12" (300 mm) for timber.

Edge & End Distances

  • Edge distance is the minimum distance from the fastener centre to the edge of the timber.
  • End distance is the minimum distance from the fastener centre to the end of the timber (along the grain).
  • These prevent splitting and ensure structural integrity. Check local building codes for exact requirements.

Common Questions

What spacing should I use for screws in timber?

For structural connections, 8 inches (200 mm) on center is a common starting point. Always check the fastener manufacturer's recommendations and your local building code for specific requirements based on timber species, fastener diameter, and load conditions.

What is the difference between edge distance and end distance?

Edge distance is measured perpendicular to the grain, from the fastener to the nearest edge. End distance is measured parallel to the grain, from the fastener to the end of the timber. Both minimums prevent the timber from splitting.

When should I use double-row (staggered) fastening?

Double-row staggered patterns are used for wider timber connections, laminated beams, and when a single row doesn't provide enough capacity. Staggering reduces the risk of splitting along the grain.

How do I calculate bolt spacing for timber connections?

Bolt spacing depends on bolt diameter. Minimum spacing is typically 4× the bolt diameter along the row, with 3× minimum between rows. End distance should be at least 7× diameter for tension loads. Always verify with engineering tables or codes.

What is perimeter fastening used for?

Perimeter fastening is used when attaching sheet goods like plywood or OSB to timber frames. Fasteners are placed around the edges of the panel at regular intervals to secure it to the structure beneath.

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