Rosboro Treated Glulam

Wet-Use vs. Dry-Use

Wet-use and dry-use are terms that are associated with in-service conditions. Usually a glulam member is exposed to water on an intermittent basis only. Any wetting is typically followed by a drying cycle, and the product never reaches a consistent wet-use condition. This situation is classified as dry-use.

The technical measure of wet-use is accepted as consistent moisture content within the beam of 16% or greater. A wet-use condition is rarely reached unless the beam is submerged in water or subjected to an artificially humid moisture condition. For example, using the chart below, a beam in an environment having a constant relative humidity of 80% and a temperature above 70° F will not reach a consistent moisture content of 16% or greater. Since a combination of high relative humidity and temperature outside of this range is seldom reached in the U.S., ambient air conditions rarely result in a wet-use classification. If there is any question regarding use condition, a licensed design professional should be retained to determine if wet-use design adjustments apply.

Wet-Use Graph

Rosboro Treated Glulam technical information.


Rosboro Treated X-Beam™

When You Need It To Last

Rosboro Treated X-Beam in Architectural Appearance is the perfect choice when you need a beam with strength, durability and beauty.

Rosboro Treated Glulam

Finally, a treated glulam that doesn't look treated! Made from coastal region Douglas fir, Rosboro's Treated X-Beam is manufactured to match standard framing widths and I-joist compatible depths, and then is treated with Hi-Clear II – a clear industrial wood preservative that leaves the beam an attractive honey-color. The treatment protects against decay, mold, bacteria, and insects, including the Formosan termite. Backed with a 25-year warranty, Rosboro Treated X-Beam products are an excellent choice for decks, porches, and balconies where appearance is critical.

Beams Are Available in Common Sizes:

Widths: 3-1/2" and 5-1/2"
Depths: 9-1/2", 11-7/8", 14", 16" and 18"

Columns Approved for Ground Contact

Rosboro Treated Column products are pressure treated with a mineral-spirit borne copper naphthenate preservative that provides an ideal fungicide and insecticide for the long term preservation of glulam columns in both ground contact and above ground uses. This treatment is effective against the dampwood termite, drywood termite and subterranean termites including the Formosan termite. Rosboro recommends that columns be placed on a pier block, but if the column is used in a direct ground contact application, then it should sit in a gravel bed that allows proper drainage. The columns are Framing Appearance and are treated with the more aggressive copper naphthenate which is intended for exterior applications. After treatment, the color ranges between chocolate-brown and dark green. Click here for more information and design values.

Rosboro Treated Glulam

Columns Are Available in Common Sizes:

•    Widths: 3-3/8", 5-1/4" and 7"
•    Depths: 3-1/2", 5-1/2" and 7"

Restricted Uses and Precautions

Rosboro Treated X-Beam and Column products should not be used in marine applications such as docks, marinas, and standing-water conditions. The treatment used for Rosboro Treated X-Beam is low in toxicity to humans, however gloves should be worn when handling treated products, and dust masks and eye protection should be worn when cutting treated beams and columns. Always follow site, handling, and disposal instructions provided by Materials Safety Data Sheets (MSDS) available on our technical reference page.

Recommended Hardware, Resealing, and Finishing

Moisture can accumulate around connections such as hangers, fasteners, bolts, nails and screws. Rosboro Treated X-Beam provides protection from moisture-induced rot and decay at these locations when fabrication is done before treating. However, field fabrication, trimming, hole drilling, and minor surface damage should be sealed with copper naphthenate (available at local home centers). Though Rosboro uses treatments that are non-corrosive to metal, we recommend using hangers and fasteners specified for treated wood products, such as hot-dip galvanized or stainless steel. Oil-based stains and paints can be applied as a final finish once the treatment has flashed off.

Code Recognized

Rosboro glulam is manufactured in accordance with ANSI Standard A190.1, which is a code-recognized national consensus standard for glulam, using wet-use adhesives complying with ASTM Standard D2559. The lay-up combinations EWS 24F-V4 DF/DF and Combination Number 50 are recognized under ICC-ES Report ESR-1940. Rosboro's glulam production is inspected and certified by APA-EWS.