What is checking?

Checking is a common moisture related phenomenon in wood. Checking occurs naturally in wood and is parallel to the natural grain direction of the piece. Glulam beams typically exhibit fewer and less severe checks than comparable size sawn timbers due to their relatively low moisture content at time of manufacture. It is often difficult, however, to control the exposure of glulam to the elements during shipping, storage, and erection. Checks are often observed near a glueline in a glulam member where differential drying stresses are greatest. This most often occurs near the outermost glueline where the amount of surface exposed by the outermost lamination is greatest. Checks are a natural characteristic of wood and are not normally considered to have a detrimental effect on the strength of the member.Glulam Checking

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Handling Glulam Beams

Inspection, Storage and Repair

Storage in the Yard and on Jobsite

  • Keep beams off the ground using lumber blocking, skids or rack system.
  • The wrapping should be left in place to protect them from moisture, soiling, sunlight, and scratches.
  • For long-term storage, cut slits in the bottom of the wrapping to allow ventilation and drainage of any entrapped moisture.
  • If possible, store glulam under cover to protect the beams from moisture, soiling and sunlight.
  • The wrappings can be left intact to protect beams during installation.
  • Seal ends of beams immediately after trimming or cutting.

Pre-Installation

  • Physically inspect each beam while on the ground.
  • Repairs are easier to make on the ground before installation.
  • Sort the delivered beams and determine which glulams will be exposed or unexposed in the finished building.
  • When used in an exposed application, and appearance is important - make sure these beams are of acceptable Appearance quality.

Repair (if needed):

  • With beams planned for exposed applications, repair appearance defects such as sunburn, forklift damage, and water damage while still on the ground.
  • Season checks should be repaired after the beam has adjusted to the equilibrium moisture content.
  • After necessary repairs have been made, use tape to close the paper wrap so that the beam is protected during the installation process.

Post-Installation

  • After the interior of the building is painted or finished, remove paper from beam and apply finish to the beam.
  • Any final cosmetic repairs (for checks and small knots, etc.) are best made after all finishes are applied to the beam.