Glulam Beams

Glulam is short for glued laminated timber. It’s made by stacking and gluing together multiple layers of dimension lumber, typically using softwood species such as Douglas Fir/Larch or Alaskan Yellow Cedar, then pressing and bonding them under high pressure to form a solid beam. That construction matters, because it’s the line that separates glulam from every other engineered beam on the rack.

For broader project planning, explore WBC’s building materials resources.

Here’s the short version of how to choose. Glulam wins when the beam will be seen, curved, or asked to carry a long span. From extra-long roof spans to curved beams and common headers to dramatic columns, glulam gives the rich, natural look of wood with engineered benefits built in. When the beam disappears into a wall and nobody cares what it looks like, LVL is often the call. Either way, the span gets engineered before anybody orders anything. That part isn’t optional.

For Montana builders, the species choice carries real weight. Glulam beams are made with exterior-grade or wet-use adhesives, suitable for many different interior and exterior applications. And Alaska Yellow Cedar is a naturally-resistant species that is a green alternative to pressure-treated wood. That’s the difference that lets glulam handle exposure that LVL can’t touch — BCI joists and Versa-Lam LVL products shall be installed in dry-use applications only. Moisture and freeze-thaw don’t forgive dry-use products used wet.

Glulam Versus the Rest of the Engineered Wood Family

The confusion between glulam, LVL, and the rest of the alphabet soup is constant at the counter. The distinction comes down to what gets bonded together.

Glulam is made by bonding dimension lumber together, whereas LVL is made by bonding thin layers of wood veneers together. More specifically, LVL is produced by bonding thin wood veneers together in a large billet so that the grain of all veneers is parallel to the long direction.

LVL is one branch of a bigger family. Structural composite lumber (SCL) includes laminated veneer lumber (LVL), parallel strand lumber (PSL), laminated strand lumber (LSL) and oriented strand lumber (OSL) — a family of engineered wood products created by layering dried and graded wood veneers, strands or flakes with moisture-resistant adhesive into blocks of material known as billets, which are subsequently resawn into specified sizes. PSL is manufactured from veneers clipped into long strands laid in parallel formation; the length-to-thickness ratio of the strands is around 300. Like LVL and glulam, it’s used for beam and header applications where high bending strength is needed, and it’s frequently used as load-bearing columns.

Then there are the I-joists that frame floors. BCI joists are specially constructed I-joists with flanges made from strong Versa-Lam laminated veneer lumber, oriented stranded board webs, and approved waterproof structural adhesives. They run 20% greater strength than comparably-sized dimensional lumber.

Where each one lands:

Product	What’s bonded	Where it shines
Glulam	Full dimension lumber	Long spans, curves, exposed beams, columns, headers
LVL	Thin parallel veneers	High-strength concealed headers and beams, flange stock for I-joists
PSL	Long parallel strands	High-bending beams, headers, load-bearing columns
LSL / OSL	Flaked strands	Studs, millwork
BCI I-Joist	LVL flanges plus OSB web	Floor and roof framing

The honest trade-off: Versa-Lam LVL beams support heavier loads and longer spans than comparable glulam or dimension lumber products. But glulam earns its keep elsewhere. Rosboro X-Beam glulam is the most cost-effective engineered wood product — 20% to 30% less expensive than LVL and up to 20% less expensive than laminated strand lumber (LSL), making it a great choice for short door and window headers too.

How to Specify a Glulam Beam

Three things drive the order: size, appearance grade, and layup. Get the layup wrong and the beam fails where it shouldn’t. Get the grade wrong and you’ve either paid for a finish nobody sees or stuck a rough industrial beam in a vaulted great room.

Sizes

Boise Glulam stock beams are manufactured in widths of 3⅛”, 3½”, 5⅛”, 5½”, 6¾”, and 8¾”, with depths ranging from 6” to 24” and lengths up to 66 feet, with or without camber. Western Building Center’s glulam stock runs Architectural-grade beams in the 3½” and 5½” widths — depths from 9” through 24” in the 5½” line, plus 5½”×5½” and 5⅛”×5⅛” columns.

When a floor system needs to line up with the joists, IJC (I-Joist Compatible) sizes are readily available and have proven to be cost-effective product options compared to other structural members such as LVL. X-Beam matches 2x10 and 2x12 depths at 9¼” and 11¼”.

Appearance grades

It’s usually easy to determine whether to choose Architectural, Industrial or Framing Appearance Classification beams.

Grade	Use	Finish
Architectural	Exposed (or concealed)	Voids greater than ¾” are filled, three sides excluding the top are planed or sanded, edges eased on the bottom face
Industrial	Concealed	Used in concealed applications or where appearance isn’t important, such as commercial buildings, warehouses, and garages. Voids are not filled, and only the two wide surfaces are planed
Framing/Header	Concealed headers	Commonly used for concealed applications such as doors and windows, in two common widths, 3½” and 5½”

One catch worth knowing on the narrow stock: stock beams are available in Architectural appearance classification except 3½” and 5½” which are Framing header classification only. WBC’s glulam list is all Architectural-grade, so those exposed-beam jobs are covered.

Layup and camber

This is the part that trips people up. Determine whether to specify a balanced or unbalanced layup. The shorthand: balanced layups (V8) for continuous or cantilevered spans, unbalanced (V4) for simple spans. On an unbalanced beam the “Top” mark has to face up — flip it and the strong laminations end up where the tension is weakest.

Camber follows the same logic. Most stock beams are available with either a small amount of camber (5000’ radius) or no camber, depending on market demands. Many glulam beams have a slight camber, intentionally designed to counteract the natural deflection that occurs when the beam supports a load. When installing, it’s important to orient it with the crown (top) facing upward to ensure proper load distribution.

For design value reference, Rosboro X-Beam design properties are 24F-V4. The published modulus matters when an engineer runs the numbers — an “apparent” MOE is typically published for wood structural products, while the true (shear-free) value runs higher.

Verifying Loads Before You Order

No glulam span is a guess. Every beam gets sized against the actual loads, and in snow country that’s not a formality — the roof load tables exist precisely because a beam that’s fine in a mild climate gets overwhelmed under Montana accumulation.

BC Calc performs engineering analysis to size beams, joists, columns, studs and tall walls. The user enters the member geometry, adds loads, holes and other relevant data and then selects a product for analysis. The program helps identify which engineered wood products meet the demands of the application. Run the loads, the span, and the deflection limit through software like that or the manufacturer’s span tables with an engineer before anything gets ordered.

Confirm bearing too. The beam has to land on adequate support — minimum bearing length per the specifier guide, with solid blocking under any point load above. And glulam works fine standing up: glulam can be used as a column or post, providing excellent load-bearing capacity and structural stability. Like other glulam applications, the selection and sizing of columns should be based on engineering considerations, taking into account the specific design requirements and loads imposed. WBC stocks dedicated 5½”×5½” and 5⅛”×5⅛” glulam columns for exactly that.

Installation and Handling

The fastest way to void a warranty or compromise a beam is to take a drill or saw to it in the field. Orient it with the crown (top) facing upward. Then leave the structure of the beam alone unless an engineer has signed off.

It is possible to drill holes in glulam beams, but it’s crucial to follow the guidelines and engineering specifications so the structural integrity isn’t compromised. The size, location, and orientation of holes should be determined by a qualified engineer or the manufacturer. Same rule applies to the LVL family — do not drill, notch, cut or alter except as approved in writing. Check the specifier guide’s hole chart before a bit ever touches the beam.

Storage is the other field error nobody thinks about until the beam’s already bowed. Keep glulam flat, dry, and covered. In a climate where lumber stored outside doesn’t stay straight through to spring, that’s not advice you skip.

A note on treatment: contact the manufacturer prior to preservative or fire-retardant treatment — unauthorized treatment may void all warranties. Don’t field-treat a beam and assume it’s fine.

Frequently Asked Questions

What is glulam? Glulam is short for glued laminated timber. It’s made by stacking and gluing together multiple layers of dimension lumber, typically softwood species such as Douglas Fir/Larch or Alaskan Yellow Cedar, then pressing and bonding the layers under high pressure to form a solid beam.

How does glulam compare to LVL? Both are engineered wood, but they’re built differently. Glulam is made by bonding dimension lumber together, whereas LVL is made by bonding thin layers of wood veneers together. Glulam is the choice for exposed, curved, or long-span work; LVL handles high-strength concealed headers and joists where appearance doesn’t matter.

Can glulam be used outside? Yes, with the right species and grade. The beams are made with exterior-grade or wet-use adhesives, suitable for many different interior and exterior applications. Depending on the species used, they can be used for internal or exposed applications — Alaskan Yellow Cedar can be used in a deck application. LVL products, by contrast, are dry-use only.

Can you drill or notch a glulam beam? Not on your own. It’s crucial to follow the guidelines and engineering specifications to ensure the structural integrity of the beam is not compromised. Generally, the size, location, and orientation of holes should be determined by a qualified engineer or the manufacturer.

Which way does the beam go up? Crown up. The camber is intentionally designed to counteract the natural deflection that occurs when the beam supports a load. Orient it with the crown (top) facing upward to ensure proper load distribution. On an unbalanced layup, that also means the “Top” mark faces the sky.

What species is glulam made from? Glulam beams can be made from various softwoods, including Douglas Fir, Larch and Alaskan Yellow Cedar. The choice of species depends on factors such as local availability, structural requirements, aesthetic preferences, and application.

Can glulam work as a column? Yes, glulam can be used as a column or post in construction. Glulam columns are straight and dimensionally true, making framing an easy task, and because they’re available in long lengths, the members don’t have to be spliced together as is often necessary with sawn lumber.