What is the difference between LVL and glulam?

LVL (laminated veneer lumber) is made from thin wood veneers (1/10 to 1/8 inch thick) glued together with grain running parallel. Glulam (glued laminated timber) is made from dimensional lumber boards (typically 1-1/2 inch thick) stacked and glued. The key practical differences: LVL is stronger per unit size for its standard dimensions, available in consistent factory sizes, and typically less expensive. Glulam is available in wider sizes (up to 10-3/4 inches and wider), can be manufactured in custom shapes (arches, curves, tapers), and has a more attractive appearance for exposed applications. For concealed structural beams and headers, LVL is the standard choice. For exposed architectural beams where appearance matters, glulam is preferred. Can engineered lumber be used outdoors?

Can engineered lumber be used outdoors?

Standard engineered lumber products (LVL, glulam, PSL, I-joists) are manufactured with interior-grade or moisture-resistant adhesives and are NOT intended for exterior or weather-exposed applications without protection. However, some manufacturers produce pressure-treated LVL and glulam for outdoor structural use, and exterior-grade glulam (manufactured with waterproof adhesives and preservative-treated laminations) is available for exposed outdoor applications like pergolas, covered walkways, and bridge beams. Always check the manufacturer's specifications for outdoor use ratings. Never use standard interior-grade engineered lumber in weather-exposed locations without enclosure and weather protection. How far can a LVL beam span?

How far can a LVL beam span?

LVL span depends on the beam size, load conditions, and manufacturer's specifications. General guidelines for residential floor loads: a single 1-3/4 x 9-1/2 inch LVL spans approximately 9-12 feet. A double 1-3/4 x 11-7/8 inch LVL (two plies bolted together) spans approximately 14-18 feet. A triple 1-3/4 x 14 inch LVL spans 18-24 feet. These are approximate ranges. Actual spans depend on the specific manufacturer's allowable load tables, the tributary load area, and local building code requirements. Always consult the manufacturer's engineering literature or a structural engineer for beam sizing. LVL beams typically span 50-100% farther than comparable solid sawn lumber.

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Framing & Structure

LVL, Glulam & PSL: Engineered Lumber Guide for Beams, Headers & Joists

Lumberama Editorial Team, Structural Lumber & Engineered Wood Specialists Feb 24, 2025 11 min read

Why Engineered Lumber

Engineered lumber products are manufactured from wood veneers, strands, or smaller pieces bonded together with structural adhesives under heat and pressure. The result: beams, columns, joists, and headers that are stronger, stiffer, and more dimensionally stable than solid sawn lumber. Engineered products eliminate the natural defects (knots, slope of grain, checks, wane) that limit the strength of solid lumber.

Engineered lumber allows longer spans (reducing the number of posts and bearing walls), more consistent performance (every beam from the factory has the same strength), and better resource utilization (small-diameter trees can be processed into large structural members).

LVL (Laminated Veneer Lumber)

LVL is made from thin wood veneers (typically 1/10" to 1/8" thick) peeled from logs on a rotary lathe, dried, glued, and pressed together in a continuous billet. All veneers are oriented in the same direction (grain parallel to the length of the beam). The billet is cut into standard sizes.

Sizes: Standard thicknesses: 1-3/4" (single ply) and 3-1/2" (double ply, matching 2x4 wall thickness). Standard depths: 7-1/4", 9-1/4", 9-1/2", 11-1/4", 11-7/8", 14", 16", 18", and 24". Lengths up to 60 feet. Multiple plies can be bolted or nailed together to create wider beams.

Uses: Headers over windows and doors, ridge beams, hip and valley rafters, garage door headers, floor beams, and scaffold planks. LVL is the most common engineered beam product for residential construction. A single 1-3/4" x 11-7/8" LVL can carry significantly more load across a longer span than a solid 2x12.

Advantages: Consistent strength (no knots or grain defects), available in long lengths (eliminates splicing), minimal shrinkage and warping, higher allowable spans than dimensional lumber.

Glulam (Glued Laminated Timber)

Glulam is made from dimensional lumber boards (laminations, typically 1-1/2" or 3/4" thick) stacked and bonded with structural adhesives. The laminations are finger-jointed end-to-end to create any desired length. Higher-grade lumber is placed in the outer laminations (where bending stress is highest) and lower-grade lumber in the core.

Sizes: Standard widths: 3-1/8", 5-1/8", 6-3/4", 8-3/4", 10-3/4". Standard depths: 6" to 72" and larger. Custom sizes and curved shapes are available. Glulam can be manufactured in virtually any size and shape, including arches and tapered beams.

Uses: Long-span beams in residential and commercial construction, exposed architectural beams (glulam has a more attractive appearance than LVL), post-and-beam structures, arched roofs, pedestrian bridges, and heavy timber applications. Glulam is the choice when the beam will be visible and aesthetics matter.

Appearance grades: Industrial (concealed applications), Architectural (visible applications, minor surface defects allowed), and Premium (highest cosmetic quality, suitable for staining and clear finishing).

PSL (Parallel Strand Lumber)

PSL is made from long wood strands (up to 8 feet long, approximately 1/8" thick) oriented parallel to the beam length and bonded under high pressure with waterproof adhesive. The long strands and high-pressure manufacturing create an extremely strong, stiff product.

Sizes: Standard widths: 3-1/2", 5-1/4", 7". Standard depths: 7" to 18". Available in column sizes (3-1/2" x 3-1/2" to 7" x 7"). PSL has a distinctive appearance with visible parallel strands.

Uses: Columns, posts, beams, and headers where high compression strength is needed. PSL is often used for point loads (columns under beams) and in exposed applications where its distinctive appearance is valued. PSL is the strongest engineered lumber product by volume.

I-Joists

I-joists have a top and bottom flange (made from LVL or solid lumber) connected by a thin OSB or plywood web, creating an I-shaped cross-section. The flanges resist bending; the web resists shear. The I-shape is extremely efficient — maximum strength with minimum material.

Sizes: Flange widths: 1-1/2" to 3-1/2". Depths: 9-1/2", 11-7/8", 14", 16". Lengths up to 60 feet.

Uses: Floor joists and roof rafters in residential and light commercial construction. I-joists span farther than dimensional lumber joists of the same depth, are lighter, and don't shrink, twist, or crown. The open web design allows easy routing of plumbing, ductwork, and electrical (with approved hole sizes and locations).