Glulam Beam Span Chart: Sizes, Grades and Typical Spans

Glued laminated timber, usually shortened to glulam, is made by bonding layers of dimensional lumber into one large beam. It can be built in almost any length and curved or cambered, which is why it shows up in vaulted great rooms, exposed ridge beams and wide garage openings. A glulam beam span chart tells you how far a given width and depth can reach under a given load, but it also introduces terms you will not see on sawn lumber tables: layup grade, stock widths and camber.

In short, you pick the table matching the beam’s job (roof, floor, or header), find the load or tributary width row, and read across to the width and depth that reaches your span. Every span quoted here is a typical example meant to show how the charts behave. The manufacturer’s or industry association’s published tables, your local code tables, and an engineer or the building department govern final sizing.

How a Glulam Beam Span Chart Is Laid Out

Glulam comes in standard widths that line up with wall framing: 3-1/8 and 3-1/2 inches for 2×4 walls, 5-1/8 and 5-1/2 inches for 2×6 walls, and 6-3/4 inches and wider for heavier work. Depths increase in increments of the lamination thickness, commonly 1-3/8 or 1-1/2 inches, so you will see depths like 9, 10-1/2, 11-7/8, 12, 13-1/2, 15, 16-1/2 and 18 inches.

Charts usually list depth down the side, width across the top, and a span or allowable load in each cell. Some tables present a uniform load capacity in pounds per linear foot at several spans instead. The notes state the design grade, the deflection limit (often L/360 for floors and L/240 or L/180 for roofs), the load duration factor, and assumptions about lateral bracing.

Typical Example Spans

These rounded figures illustrate how spans grow with depth for a common 24F grade beam carrying a light roof load in a modest snow area. They are examples, not design values. Your manufacturer’s tables, local code and an engineer govern.

Heavy snow, a bonus room above a garage, or point loads from posts can cut those numbers considerably. Use them as a sense of scale, then open the actual table.

Layup Grades Like 24F-V4 Explained

Glulam grades describe how the laminations are arranged. In a designation like 24F-V4, the “24F” means an allowable bending stress of about 2,400 psi, and the “V” means the beam uses visually graded laminations (an “E” would mean mechanically graded). The final number identifies the specific layup combination.

The important practical point: most stock beams are unbalanced layups, with the strongest laminations placed on the bottom, where tension is highest in a simply supported beam. Unbalanced beams are stamped “TOP” on one edge. Install them upside down and capacity drops significantly. Balanced layups, often labeled with a V8 designation, have strong laminations top and bottom and are used for cantilevers and continuous beams over multiple supports where the top edge also sees tension.

When reading glulam timber span tables, confirm the grade the table assumes matches the stamp on the beam you are buying. A table built for a higher grade will overstate the span of a lower grade beam.

Camber and Why It Matters

Camber is a slight upward curve built into a glulam during manufacturing, so that the beam settles closer to level once loaded. Stock beams for roofs often carry a gentle camber based on a large radius. For an exposed ridge beam, camber can be welcome. For a floor beam or a header where flat drywall or a level door head is needed, a large camber can create a visible hump. Many suppliers stock beams with minimal or zero camber specifically for floors and headers. Ask before ordering.

Using a Glulam Span Chart for Ridges and Garage Headers

Ridge Beams

A structural ridge beam carries half the roof on each side, so its tributary width equals half the rafter span on the left plus half on the right. Because the rafters do not push outward on a structural ridge, vaulted ceilings become possible without ceiling ties. The ridge must be supported by posts at each end, and those posts carry large loads straight to footings. A glulam beam span chart for ridge beams typically asks for the roof snow load and the tributary width.

Garage Headers

Double garage doors at 16 to 18 feet are classic glulam territory. A glulam header in a 2×6 wall at 5-1/8 or 5-1/2 inches wide sits flush with the framing. If there is a bonus room or second floor above, the load jumps and an engineer should size the beam. Garage walls also need bracing beside the opening to resist wind and racking.

When Glulam Beats LVL

• Exposed beams: glulam is available in architectural and premium appearance grades that look like solid timber. LVL shows glue lines and is usually hidden.
• Long single pieces: glulam is easy to source in long lengths and very large depths for great rooms and wide openings.
• Single-piece wide beams: a 5-1/2 inch glulam is one solid member, while LVL needs three plies fastened together.
• Curves and camber: glulam can be manufactured curved or cambered.

LVL often wins for hidden headers and flush floor beams, where its high stiffness, flat profile and wide availability at lumberyards make it convenient. Both are engineered products, and both are sized from their own makers’ tables.

Step-by-Step: Sizing From a Chart

1. Measure the clear span and note how long the bearing will be at each end.
2. List all loads: roof, snow, floors, walls and any posts above.
3. Open the glulam beam span chart for that use and your snow load.
4. Locate the tributary width row, rounding up.
5. Pick the width that fits your wall and read down to a depth that meets your span.
6. Confirm grade, camber and bearing length, then have the size checked by the supplier’s design tool or an engineer.

Troubleshooting

• Beam installed upside down: check for the TOP stamp. If it was flipped, have an engineer evaluate before loading it.
• Hump in the ceiling: the beam likely has more camber than the application wanted.
• Checking or surface cracks: exposed glulam can check as it dries. Usually cosmetic, but large checks near bearings should be inspected.
• Crushing at supports: bearing length or post size was too small for the reaction.

Typical Cost Ranges

Glulam is priced by size and appearance grade. Stock framing-grade beams for hidden use commonly cost somewhat more per foot than equivalent LVL, while architectural grades for exposed work cost more again. A typical garage header might run from a few hundred dollars to over a thousand depending on length and depth, and exposed ridge beams for great rooms can cost several thousand with delivery and lifting equipment.

Structural Safety Notes

Large glulam beams are heavy; plan lifting with enough people or equipment and never stand under a suspended beam. Support ends on posts or jack studs that carry loads to footings, and use connectors and post bases rated for the reactions. Exterior and garage beams may need uplift straps for wind. Call 811 before digging footings and confirm permits and HOA rules for exterior changes.

When to Call a Licensed Professional

Structural ridge beams, garage headers under living space, cantilevers, and any beam carrying point loads should be designed by an engineer and installed by a licensed contractor. Most jurisdictions require a permit and inspection for structural framing. Any electrical, plumbing or HVAC runs affected by the work need licensed trades.