Why Beam Span Calculations Matter

Proper span calculation ensures structural integrity and safety. Incorrectly sized beams can lead to sagging floors, roof collapses, or costly repairs. This calculator helps determine the minimum depth required for common materials based on span and load.

Calculation Steps

Measure the clear span between supports in feet
Determine total load (dead + live load) in pounds per square foot
Select material type for modulus multiplier
Calculate minimum depth: (Span² × Load) / (Material × 100)

Example Scenarios

Deck Joist: 8ft span, 50psf load → 3.2" depth in Douglas Fir
Floor Beam: 12ft span, 40psf load → 5.76" depth in LVL

Reference Values

Material	Modulus Multiplier	Typical Use
Pine	1.5x	Light structural
Douglas Fir	2.0x	General framing
LVL	3.0x	Heavy loads

⚠️ Important Notes

Always add 10-15% safety margin to calculated values
Consult local building codes for legal requirements
Consider deflection limits for floor/ceiling applications

Span Calculator Joist Rafter Beam

Results

Why Beam Span Calculations Matter

Calculation Steps

Example Scenarios

Reference Values

⚠️ Important Notes

Load Unit Converter

Frequently Asked Questions

Q: What's the difference between joist and beam spans?

Q: How do I account for snow load?

Q: Can I use this for ceiling joists?

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Span Calculator Joist Rafter Beam

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