Structural Beams: Glulam, LVL, PSL and Solid Timber

Solid sawn timber

A solid sawn beam is cut from a single log — 4x, 6x, 8x and larger sections in Douglas Fir, Southern Yellow Pine, Hem-Fir or, in timber frame work, species such as White Oak. It is the simplest and often the least expensive option for short spans and modest loads.

The tradeoffs are length and moisture. Solid timbers are usually stocked to about 20–24 ft, and large sections are frequently sold green or partially air dried, so they check and shrink as they reach equilibrium. That movement is cosmetic in most framing but matters for exposed beams and tight connections.

• Common sizes: 4x6 through 12x12; lengths typically 8–24 ft
• Best for: short spans, exposed rustic timber work, posts and sills
• Watch for: checking and shrinkage as green timber dries; limited long lengths

Glulam (glued laminated timber)

Glulam beams are built from dimensional lumber laminations bonded face to face with structural adhesive. Because the beam is assembled rather than cut from a log, glulam is available in very long lengths and deep sections, and can be manufactured with a camber or as a curved member.

Glulam is produced in appearance grades. Industrial is intended to be hidden, Architectural and Premium are surfaced for exposed applications. If the beam will be seen, the appearance grade belongs on the quote request — it materially affects price.

• Common widths: 3-1/8", 3-1/2", 5-1/8", 5-1/2", 6-3/4"
• Common depths: 9" through 24"+ in 1-1/2" laminations
• Best for: long spans, exposed ridge and garage beams, curved members
• Specify: appearance grade, camber, and whether the beam is protected from weather

LVL (laminated veneer lumber)

LVL is made from thin wood veneers bonded with the grain running parallel to the length. The result is a very uniform, predictable member with high bending strength and almost none of the variability of solid sawn lumber.

LVL is the workhorse of residential headers and floor beams. It is dimensionally stable and can be multi-plied on site — two or three plies fastened together to reach the required width. It is not an appearance product and is not intended for weather exposure without protection.

• Common thicknesses: 1-3/4" plies, multi-plied to 3-1/2" or 5-1/4"
• Common depths: 9-1/2", 11-7/8", 14", 16", 18"
• Best for: headers, floor beams, hip and valley rafters
• Watch for: not for exposed or wet locations; follow the maker's nailing pattern for multi-ply builds

PSL and LSL

Parallel strand lumber (PSL) is made from long veneer strands and carries very high loads in relatively compact sections, which makes it a common choice for heavily loaded columns and long-span beams. Laminated strand lumber (LSL) uses shorter strands and is typically used for rim board, headers and tall wall studs where its uniformity and screw-holding matter more than peak strength.

Both are engineered products with published design values from the manufacturer. Substituting one for another is not a field decision — the design values differ.

• PSL: high-capacity beams and columns; common widths 3-1/2", 5-1/4", 7"
• LSL: rim board, headers, tall studs; excellent fastener holding
• Both require manufacturer design values for sizing

What a supplier needs to quote a beam

Beam quotes stall most often because the request is missing load information. A supplier can price a specific part number instantly, but cannot pick the beam for you without knowing what it carries.

• Clear span between supports, and the bearing length available at each end
• Tributary width — how much floor or roof area the beam carries
• Whether the beam supports a roof only, floor, or floor plus a wall above
• Maximum depth you can accommodate in the assembly
• Interior/protected or exposed to weather
• Exposed to view (drives appearance grade) or hidden
• Any point loads from posts or girders landing on the beam

Sizing responsibility

Span tables and calculators are useful for scoping a project and sanity-checking a design, but a beam that carries concentrated or unusual loads should be sized by a licensed structural engineer, and most jurisdictions require engineered documentation for permit. Lumberama supplies materials and does not provide structural engineering.