Garage Header Sizing Guide

Garage doors are the biggest weak point in a house during hurricanes. The wider the door, the bigger the header you need. Select your garage size below to see the header requirements.

16' Max Span

LVL Engineered

6,720 Lbs Force

Interactive Garage Header Calculator

2x LVL 1-3/4"x14"

Single

Single+

16'

Double

18'

Triple

Opening Width 16 feet

Wind Force (60 PSF) 6,720 lbs

Required Header 2x LVL 1-3/4"x14"

Header Types by Garage Size

Bigger openings need stronger headers. Here is what you need for each garage configuration in Palm Beach County HVHZ zones.

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Single Car

8-9 feet wide

Doubled 2x12

Standard lumber OK for single
Must be #2 or better grade
Solid blocking at ends
Simpson connectors required

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Double Car

16 feet wide

LVL or Steel

Engineered lumber required
1-3/4" x 14" LVL minimum
Or W8x18 steel beam
Post supports at each end

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Triple/RV

18+ feet wide

Steel Required

Steel beam only at this width
W10x22 or larger typical
Engineer design required
Special foundation support

Frequently Asked Questions

Common questions about garage door headers in hurricane zones.

What size header do I need for a 16-foot garage door in Palm Beach?

A 16-foot garage door opening typically requires an engineered header like a 1-3/4 inch x 14 inch LVL beam or a steel W8x18 beam. Standard lumber headers cannot span this width safely in HVHZ wind zones. The header must carry both wind loads and any roof/floor loads above.

Why do garage doors have the biggest wind load problems?

Garage doors are often the largest opening in a house, sometimes 16 feet wide or more. More area means more total wind force. A 16x7 foot garage door in a 60 PSF wind zone takes 6,720 pounds of force - like a small car pushing against it. All that force transfers to the header.

Can I use regular 2x lumber for a garage door header?

Only for single-car garages up to 9 feet wide, and even then you need doubled or tripled 2x12 lumber. Double-car and larger openings require engineered lumber (LVL, PSL) or steel beams. Using undersized headers in hurricane zones can cause catastrophic roof failure.

How does building height affect garage header sizing?

Taller buildings experience higher wind pressures, especially above 15 feet. A two-story home needs a bigger garage header than a single-story home with the same door size. Wind speed increases with height, and pressure increases with the square of speed.