From this site

One project, every trade

Each calculator adds its lines to a single estimate — consolidated BOM, schedule and cash-flow included.

Open My Project →

Collar Tie Wind Uplift Tension Calculator

Estimate tension force in a roof collar tie from wind uplift pressure and tributary area.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax

Collar tie tension force

12 kN

Check your inputs

Simplified tributary-area estimate — a full load path/connection analysis by a structural engineer is recommended for critical uplift connections.

Running these inputs gives 12 kN as the collar tie tension force. Note that number of ties sharing this load sits at the low end of the range this calculator was checked against, so treat the output as indicative rather than settled. Expect some drift against the real job; the calculation is solid but conditions on site are not. Currently reading for United States under IRC 2024 — pick a different market above and the figures re-cast accordingly.

Add the equipment this sizes

This result is a specification — 12 kN — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Simplified tributary-area method: tie tension = uplift pressure × tributary roof area ÷ number of ties sharing that tributary area

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

Why does wind create tension in a collar tie?
Wind uplift pressure tends to lift the roof rafters upward and outward; the collar tie resists this by developing tension force, transferring the uplift load down through its connections at each rafter.
How is the tributary area determined?
It's the portion of roof area whose uplift load is carried by this specific collar tie — generally the tie spacing multiplied by the horizontal distance the tie's connection influences on the roof.
Is this a full structural design check?
No — it's a simplified tributary-area estimate only. Critical uplift connections should be verified with a full load path and connection analysis by a structural engineer.