208-756-4248

TECHNICAL INFORMATION

ADHESIVES

QB uses durable waterproof structural adhesives in the manufacturing process. Both PRF and Melamine adhesives are available.

Adhesives have been tested to comply with ASTM 2559, CSA and JAS standards. For a more complete list of testing and approvals see the attached PDF.

Adhesive qualification and test results

AVAILABLE SPECIES
  • Doug Fir/Larch
  • Alaskan Yellow Cedar
  • Southern Yellow Pine
  • Western Red Cedar
  • California Redwood
  • Others upon request
CHECKING

Checking is a natural phenomenum of wood that occurs when wood dries and shrinks. The stresses built up from the shrinkage will cause a small split to occur. This typically is not an issue if the checking unless the checking is very severe.

QB places a great deal of attention to moisture during the manufacturing process. All of our raw materials are dried to specific moisture contents and we monitor this throughout the assembly process. Since shrinkage is the result of moisture leaving the board, the attention QB places on this will minimize any checking you may see in the beams. However as wood is a natural material and some locations tend to be very dry climates some checking may still occur. It is also important the the product be properly handled and stored during any inventory or installation process to minimize checking issues.

  • For information on checking and it’s impact to structural performance please refer to AITC technical note #11.
  • For information on evaluating the impact of actual checking in the field see AITC technical note #18.
  • For “Owners Guide to Understanding Checks in Glued Laminated Timber” see F450
  • For “Evaluation of Check Size in Glued Laminated Timber Beams” see R475.
FIRE RESISTANT DESIGN

Since wood is a combustible material, many design professionals do not consider wood as part of an effective fire resistant design. With proper design and care, wood can successfully be used in many structures that require fire resistant design.
For most light weight construction, fire resistance is provided by a covering of gypsum or other insulating materials or by fire sprinklers. This is true for wood, steel or even concrete.
Glulam beams with proper design can accomplish fire resistant design by using larger sections. Using woods natural characteristics to char when exposed to high temperature and combustion. This charring develops a natural insulation to fire protecting the interior wood fiber from the high temperature and flame. Of course this charring only protects the wood for a relatively short time, just as insulation or gypsum protects other products for a short time.
Bottom line, you can protect your structure and have the appearance you desire by designing your QB members for fire resistance construction. This is an area you should consult a licensed design professional although some basic information is available in the Timber Construction Manual, published by the American Institute of Timber Construction.

APA Technical Notes:

QUALITY ASSURANCE

At QB our aim is not to be average but to stand out in quality. Since our founding we never could produce our products to the minimum acceptable standards and feel good about it. All of the product produced at our facility is covered under APA-EWS quality assurance program. Rigorous independent audits ensure fabrication methods meet or exceed industry standards.

QB quality technicians work hand in hand in the plant with production personnel. They enjoy the full support of management on making quality related decisions and in the long run, every member in our plant is fully engaged in our quality program. “Quality is built in” is more than a catch phrase for us. We select quality vendors for our raw material and then carefully grade and process it into a finished product. Every piece is graded and monitored for appropriate moisture content to ensure proper gluing and curing.

Tension Finger JointsAttention to detail in all aspects of the operation makes the difference between mediocre and excellent product quality. No where is this attention to detail more important than in the area of finger joints. Finger joints are basically glued connections that make long pieces of wood out of short pieces through the use of “fingers” cut into the ends of the boards. These joints transfer forces from along the board to the adjoining board. It takes significant care to make a quality joint. The fit of the joint, the application of adhesive, and the pressure and cure are all important aspects to making this critical component of beam construction work. All tension laminations are proof loaded to ensure both the lumber and the finger joint will handle the stress levels that are assumed for the design.

STANDARD BEAM LAYUPS

The purpose of this section is to provide information relating to beam selection and to help avoid some common errors made in the usage of glulam products. Most glulam beams are manufactured using one of three types of layups:

Balanced – V8

  • For applications that have cantilevers or are multi span applications (supported by columns or walls anywhere in mid-span).
  • V4 and V8 BEAMS are surfaced on three sides, top stamped, with two bottom edges eased.

Balanced Beam Layout

Unbalanced – V4

  • For simple span members supported only on the ends with no cantilevers.
  • V4 and V8 BEAMS are surfaced on three sides, top stamped, with two bottom edges eased.
    Inverting a V4 Beam Reduces the Bending Design Value by 25%

Columns – Combination 2 or V8

  • Combination 2 for use as vertical columns only.
  • COLUMNS are surfaced on four sides with all edges eased.

Placing unbalanced beam upside down

VOLUME EFFECTS

It has been long known and proven that large structural members do not have the same strength per unit of size as smaller members. The theory behind this is weak link analysis which suggests that the larger the area the more potential area will contain a strength limiting defect.

Testing has proven this theory and industry quidelines have been set up that take a reduction in allowable stresses for large members. Span charts and load tables will already incorporate this factor.

For designers using large members they should always consider volume effects in their structural calculations. AITC publishes a document detailing proper use of this factor.

aitc_tn_21-october_2005

PRESERVATIVE TREATMENT

QB recommends the use of Coastal Douglas Fir or Southern Yellow pine for product that is to undergo chemical preservative pressure treatment. Treatments should be oil based or as specified by the project designer.

We do not offer treating services but can outsource this if you do not have your own capabilities. We do offer incising to allow better chemical penetration and retention. This is highly recommended on any product that is to be treated for outdoor use. Our incising equipment can handle large industrial beams that are typically used in industrial structures. We can also incise the tapered faces of tapered beams.

As an alternative to pressure treating some customers are moving to Alaskan Yellow Cedar, a species that is naturally durable to insect attack and decay. QB is an approved fabricator of this species. Call our customer service desk at 208-756-4248 if you have further questions.