Collar Tie Calculator Pro (USA) – Roof Framing Tool

Collar Tie Calculator Pro (USA)

Professional Roof Framing Tension & Layout Tool

ft
psf
Typical: 30psf (Snow) + 10psf (Dead) = 40psf
ft
Typically upper 1/3 of rafter length.
Pitch Tie
Tension Force
0 lbs
Total force pulling ties apart
Recommended Lumber
–
Based on typical No. 2 SPF
Board Length
0 ft
Cut length for each tie

What is a Collar Tie?

In USA residential construction, a collar tie (also known as a collar beam) is a horizontal member connecting two opposing rafters near the upper third of the roof. Its primary engineering purpose is to prevent the rafters from spreading apart under load, specifically to resist the uplift and separation caused by wind loads or unbalanced snow loads.

Collar Tie vs. Rafter Tie

Users often confuse collar ties with rafter ties. While both connect rafters:

  • Rafter Ties: Located at the very bottom (ceiling joists level). They resist the horizontal thrust of the entire roof weight.
  • Collar Ties: Located higher up (upper 1/3). They primarily resist wind uplift and are not typically designed to carry the full weight of the roof (that’s the job of the walls or ridge beam).

IRC Building Code (USA) Compliance

According to the International Residential Code (IRC), collar ties should be spaced no more than 4 feet apart. They must be a minimum of 1×4 nominal lumber. However, for higher loads or wider spans, our calculator recommends larger sizes (like 2×4 or 2×6) to ensure safety and structural integrity.

Disclaimer: This Collar Tie Calculator Pro (USA) is intended for estimation and educational purposes only. Structural engineering requirements vary by local jurisdiction (e.g., high snow load areas in the Northeast vs. seismic areas in California). Always consult a licensed structural engineer or local building authority before construction.