Construction Sales Co., Inc. is committed to answering all of your questions concerning our glulam timber. Find answers to some of our most frequently asked questions below:
Q: What species of wood do you offer?
A: For glulam we offer Southern Pine. For our heavy timber we offer Southern Pine, Douglas Fir, Cedar, and Cypress.
Q: Can glulam members be used outdoors?
A: Yes. Members that are exposed to the elements can be pressure treated prior to laminating, which allows them to resist decay. Members that are protected by a roof don’t need this treatment.
Q: What is the difference between treating glulam “before gluing” vs. after gluing?
A: When treating beams after gluing, only the outer portion of the member is treated. In many cases, this is sufficient. However, if more treatment is needed, treatment should be done prior to gluing. With this method, the individual laminations are pressure treated to the required retention, then planed to an adequate gluing surface, and then the gluing process occurs. When used with treatments such as pentachlorophenol, this gluing method forms a superior bond.
Q: Can I drill holes through glulam members for the purpose of installing light fixtures, sprinkler systems, etc.?
A: In most cases, drilling such holes is fine. However, we recommend getting approval from a professional engineer before doing so to ensure you won’t be compromising the beam’s structural integrity. AITC tech note 19 provides additional information regarding this subject (see Resource page).
Q: Can glulam meet “heavy timber” requirements?
A: Yes. Refer to the minimum sizes as determined by standard building codes, as well as our standard size chart, available on the Resources page.
Q: My specs call for glulam members that are “exposed to weather” to be pressure treated. What does that mean?
A: Just because a member is on the exterior part of a building or is part of an open-air structure does not necessarily mean that the member is subject to weather deterioration. Terminology such as “exposed to weather” found in many specs can be misleading and should not be used. AWPA U1 states that when a member is protected from moisture under a roof overhang, the member does NOT require treatment.
For over 50 years, many companies in the glulam industry have used the following rule of thumb: this rule constitutes drawing a line beginning from the outer most edge of the roof down at a 30 degree angle towards the structure. If the line touches the beam, then it needs to be treated. Otherwise, the beam is protected and does NOT need to be treated, thus saving you money. (We disagree with the extreme position of AITC in their rule of thumb calling for a 64 degree angle to be used. As long as wood remains at a moisture content of 19% or less, wood will not decay. See Resource page for available data).
Q: How do I know which grade of glulam I need?
A: AITC grades are for appearance purposes only (and not related to strength). For concealed members or when appearance is not a concern, select industrial or framing grade for appearance. If members will be publicly visible and need to be aesthetically pleasing, then select architectural or premium grade for appearance.
Q: Which stress combination should I use?
A: Stress combinations vary with species. For typical Southern Yellow Pine members, combination 24F-V1, 24P-V3, or 24F-V5 should be used.
Contact our staff when you have any further questions about our glulam timber products. We serve clients in Arkansas, Oklahoma, Kansas, Missouri, North Mississippi, West Tennessee, and the surrounding areas.