FAQ

Western Structures™ Custom Glulam FAQs

What is camber?

Camber is a "crown" purposely built into a glulam at the time of manufacture. It is most often desired in long span applications to counteract dead load deflection. Camber does not affect the strength of the beam. Residential stock beams are normally made with either a 5000' radius or zero camber, while other engineered wood products are zero camber. Most residential spans are less than 24', and the camber derived from a 5000' radius falls inside industry accepted manufacturing tolerances for zero camber beams. Stock glulam beams are increasingly popular because they contribute to a "flat" framing system without humps. The slight radius also reduces deflection or sag on longer spans.

How long is the lead time for glulam beams?

Rosboro’s flagship glulam is the stock X-Beam®, and our distribution partners keep the most commonly used sizes of X-Beam® in inventory. This means you can typically get your beams delivered the same or next-day.  For more unique beams, our Western Structures division can custom manufacture and ship as quickly as one week from time of order. You can locate a Rosboro distributor by visiting https://rosboro.com/find-a-distributor/

X-Rim™ | Next-Generation Rim FAQs

Is Rosboro X-Rim available in full framing widths?

Yes, Rosboro X-Rim is manufactured in both 3 ½” and 5 ½” widths to fit flush in any exterior wall system.

Does Rosboro X-Rim meet the 2-Hour fire rating for Type III construction?

Rosboro X-Rim is not a fire-retardant-treated (FRT) product, however, in construction where the rim board is required to be 2-hour fire rated glulam rim boards can achieve this rating while safely carrying the design loads. International Building Code Section 722 allows for calculated fire resistance of exposed wood members to be determined from Chapter 16 of the ANSI/AF&PA National Design Specification for Wood Construction (NDS). In a fire the outer portion of a glulam member becomes charred. This layer of charred wood then functions as an insulator helping to protect the undamaged interior of the member from the heat. Chapter 16 of the NDS provides the necessary calculations to determine this effective char depth.

X-Beam™ | Next-Generation Glulam 24F-V4 FAQs

How does Rosboro make full-width 3 ½” and 5 ½” Architectural Appearance X-Beam®?

X-Beam® is produced using our unique over-dimension lumber feedstock which is produced at Rosboro’s sawmill. This allows us to fill, plane, and sand the finished beam to an architectural appearance and still maintain a full-framing-width product. Other glulam producers start with standard dimension lumber and finish their beams down to 3 1/8” and 5 1/8” widths that do not fit the wall framing.

What does it mean when you say X-Beam® has an Architectural Appearance?

When producing our full-framing width stock X-Beam® we smooth sand both sides and the bottom face, fill any voids over ¾”, and ease the bottom edges. This means your stock beam can be used in any application, including those where the wood is left exposed for aesthetics. X-Beam® is ready for stain or paint without costly additional jobsite work.

Why is there a “TOP” stamp on my beam?

Glulam beams are manufactured in both Balanced and Unbalanced layups. The stock Rosboro X-Beam® (24F-V4) is an unbalanced layup. In unbalanced beams, the design stress of lumber used on the tension (bottom) side of the beam is higher than the lumber used on the corresponding compression (top) side, allowing a more efficient use of the timber resource. To assure the proper installation of Rosboro X-Beam® products, the top of the beam is clearly stamped with the word "TOP", which should be installed upward.  Other Rosboro products, such as Big Beam DF®, X-Rim, and ESL 1.6E are balanced because they are more commonly used in applications that require that flexibility.

Why is there a crack in my Beam?

This is most likely what’s called a seasoning check. Glulams are subject to the same seasoning checks or “cracks” as other wood products. Due to the shrinking of wood fibers as moisture is lost to the surrounding atmosphere, this happens naturally. Often, checks will be found near the first glue line, as the bottom lamination has more surface area exposed to the air. Also, a check will normally be found near a glue line where it meets resistance from another lamina. Because of its lower moisture content, glulam will tend to experience less seasoning checking than solid sawn timber, and rarely is the strength of the member compromised. APA publishes the "Owner’s Guide to Understanding Checks in Glued Laminated Timber", a link to which can be found in the APA Technical Publication section of our Resource Library. Still have concerns? Call our Technical Service hotline at (877) 457-4139 to speak with an expert.

Can you stain or paint Glulam beams?

Yes, absolutely. We recommend using oil based paints and stains. Water based paints and stains can cause the glulam to swell and promotes checking.

Do I need a balanced beam (like a 24F-V8) in a two-span or Cantilever application?

No, this is an old rule of thumb created when design calculations were all done manually. To save time, designers used to automatically specify a balanced beam in any multi span or cantilever condition. By calculating the beam needed for the longest simple span, they could then use that same size beam for the multi span and cantilever scenarios by specifying balanced layups. A balanced beam is typically more money will not be in stock at distributors, which costs you valuable time. With today’s design software it’s quick and easy to evaluate each span for the most cost-effective beam.  90+% of the time a stock unbalanced X-Beam will work, saving you time and money.

X-Beam™ Columns FAQs

Can glulam products be exposed to the elements?

Untreated glulam that is normally used in residential construction is not recommended for exposed conditions. Although waterproof adhesives are used in the manufacturing of the beams, Douglas Fir and Southern Yellow Pine woods react unfavorably without proper care. Pressure treatment to American Wood Preservers Association (AWPA) standards, use of naturally decay-resistant wood species such as Alaskan Yellow Cedar, or maintaining a weather-resistant surface coating is required. We have found that any Type A–Oil; Type C–Light Hydrocarbon solvent carriers work well with glue laminated beams. We do not recommend the use of waterborne treatments such as ACQ and ACZA because it will damage the wood fibers in the beam.  Waterborne treatments will void any manufacturers’ warranty.

What’s the difference between “wet-use” and “dry-use” conditions?

"Wet-use" and "dry-use" are terms associated with end-use conditions and their applicable design stresses. Intermittent exposure to the elements, followed by drying, still refers to "dry-use" even though the glulam beam could be described as wet. The technical measure of "wet" is consistent moisture content within the beam of greater than 16 percent. It is important to emphasize that a moisture content of 16 percent is rarely reached unless the beam is submerged in water, subjected to an artificially humid moisture condition, or in direct contact with the ground. Even in a highly humid artificial moisture environment, moisture content of 16 percent is only reached under unique combinations of relative humidity and temperature. For example, even a beam in an environment having 80 percent relative humidity and a temperature above 70 degrees Fahrenheit will not reach equilibrium moisture content of 16 percent. Because this combination is rarely found in the U.S., ambient-air conditions rarely result in wet-use conditions. However, pockets of moisture may collect even though the wood is protected from decay hazards by pressure treatment.

Do you publish a price list?

If you would like a price list, please contact our Lumber Sales office at (888) 393-2304 and we’ll get you set up.

Can I wrap my Glulam with siding or other materials?

We do not recommend fully encasing a glulam beam, especially in exterior applications. If any type of siding or decorative piece is specified, make sure the beam has adequate ventilation and weep holes to prevent excess moisture from puddling.

What type of glue is used to produce Rosboro glulams?

We use a resorcinol resin that is brownish-red in color for all of our glulam products. This is a waterproof adhesive, however glulams will still need to be pressure treated if intended for use in exterior applications.

Big Beam DF™ 30F-E/DF2 FAQs

Can I cut and drill holes in glulam beams?

Yes. You can cut or drill holes in glulam beams up to 2/3 of the depth! Glulam is  engineered with specific laminations of varying strength and stiffness properties, so certain areas beam need to be protected. View more information for both small and large diameter holes in the APA Technical Resources section of our Resource Library.

Is there a cost-effective alternative to expensive high-strength LVL and PSL?

Yes, there is. For these applications Rosboro has developed a hybrid glulam beam called Big Beam DF®. Unlike LVL and PSL, glulams are manufactured to maximize the efficiency of the raw material’s engineering properties using the same principle applied in “I” joists. Glulams are built in a specific pattern, so high strength material is placed in the tension and compression zones (top and bottom) and lower grade wood is used in the core. The Big Beam DF® hybrid glulam uses high strength LVL for the top and bottom laminations and standard Douglas fir for the core. The result is a 30F, 2.2E (true) beam that meets or exceeds the capacity of LVL and PSL at a much more economical cost. Rosboro Big Beam DF® is lighter and more stable than other hybrid glulams because we use DF and not Southern Yellow Pine. It is also much easier to cut and nail into than most other high strength EWP. You’ll find Big Beam DF® in stock at many of our distributors.

I installed my glulam beam upside down, is it ok?

By installing the beam upside down, you lose approximately 25% of the beam strength. If possible, flip the beam to the correct orientation. If flipping the beam is not possible, please consult with a licensed professional to decide if the beam is still adequate for the application.

Can I use glulam on my green construction projects? Do Rosboro glulam products qualify for LEED credits?

Absolutely! Wood is the most environmentally friendly and sustainable building material in the world. APA has published a detailed Green Verification Report for Rosboro products that outlines which LEED credits are available depending on the standard you are using. You can download this report from the Product Specification and Code Report section of our Resource Library.

What is the difference between True E and Apparent E?

Apparent E, the MOE value published for timbers and other solid sawn lumber products, is easiest to work with because it includes both bending deflection and shear deflection. True E does not. Some engineered wood products manufacturers focus their marketing on the True E of their products. Be careful with this; when using True E you must calculate the shear deflection separately from the bending deflection and the two values must be combined for code-compliance.

Rosboro Manufactured Timber | RMT® FAQs

How has Rosboro worked to improve quality?

In our commitment to Building Better™ for you, Rosboro has invested in new technology throughout the stud mill. Our improvements at the headrig, resaw, and edger systems help us hold better size tolerances. Our improvements at the dry kilns give us better drying consistency and our new planer auto grade and sorter systems allow us to offer a wide variety of premium quality products for you.

Is Rosboro RMT a direct substitute for solid sawn lumber and timbers?

Yes, Rosboro RMT products have been certified by the West Coast Lumber Inspection Bureau (WCLIB) to be interchangeable with dry solid sawn lumber and timbers. All RMT products are manufactured to meet or exceed the WCLIB criteria for a Douglas Fir No. 1 design values.

Is CLT “Cross Laminated Timber” the only way to build a solid wood floor system?

No, there are other decking options that give you the solid wood floor look and feel such as nail laminated decking (NLD), Glue Laminated Decking (GLD), and other products with lumber orientated vertically. Glue Laminated Decking has been around for decades, used primarily for wood bridges and industrial floors. With the expansion of mass timber construction GLD is an ideal option because it is easier to design, easier to install, and is stronger than CLT.

Studs FAQs

Do your studs have any prior selection?

Rosboro studs are No Prior Selection, meaning Rosboro does not pull the best wood out of the units.

Does Rosboro treat its lumber with anti-stain?

Yes. Anti-stain is applied right after planing as the wood travels through an in-line spray booth. The formula we use will last up to 120 days, helping to keep our product bright and fresh for that time period.

Are your KD Hem-Fire studs Hemlock or White Fir?

We manufacture studs using both species but we do not separate them during manufacturing. The product we sell as "Hem-Fir" is typically Coastal Hemlock, which grows west of the Cascade Mountain Range. Our Hemlock generally comes from Western Oregon and Southwest Washington. We also manufacture a True White Fir, which grows in Eastern Oregon and parts of Northern California.

Dimension Lumber FAQs

Contact Rosboro

P.O. Box 20
2509 Main Street
Springfield, OR 97477

Corporate Office: (541) 746-8411
Corporate Fax: (541) 726-8919
Toll-Free Sales Office: (888) 393-2304
Toll-Free Technical Service: (877) 457-4139
Sales Fax: (541) 726-0972