Post Frame Glulaminated Columns

Post Frame and Glulaminated Columns

When it comes to using glulaminated columns in post frame buildings, most envision ones where lower portions (usually six to 10 feet) are pressure preservative treated and upper remain untreated. Most of these are products of highly graded Southern Pine and/or MSR (Machine Stress Rated) or MEL (Machine Evaluated Lumber).

For columns to be mounted into ICC-ESR Code conforming wet-set brackets there are other alternatives. Standard glulams for construction typically have a Fb (fiberstress in bending) of 2400 pounds per inch. This compares favorably to familiar pressure treated lower glulams, where most have a Fb rating of roughly 1900.

There are four basic appearance classifications for glulam beams as defined in APA-EWS Form No. EWSY110 and ANSI A 190.1 (although in ANSI A190.1 they are referred to as glulam appearance “grades”). Classifications are as follows: Framing, Industrial, Architectural and Premium. These classifications are summarized below and relate to a glulam beams’ appearance only, not to its strength.

Framing Appearance

This classification is provided to match standard dimensional lumber widths (typically 3-1/2” and 5-1/2” widths). Glulam members will be planed in a “Hit and Miss” fashion. Low laminations, glue smear and glueline squeezeout are permitted. Knot holes, splits and wane are also permitted and will not be filled.

Industrial Appearance

This classification should be used (specified) when appearance is not of primary concern. Loose knots and knot holes appearing on the wide face of laminations (beam bottom) exposed to view will be filled with putty, but voids appearing on lamination edges will not. Occasional misses, low laminations or wane are permitted.

Architectural Appearance

This is a high quality appearance suitable for applications where appearance is important but not an overriding consideration. All exposed knot holes and voids measuring over ¾” will be filled with a wood-tone filler. Exposed surfaces will be smooth and bottom corners (edges) will be eased.

Premium Appearance

This is the highest standard glulam appearance classification. All exposed knot holes and voids will be filled with a wood-tone filler. Exposed surfaces will be smooth and bottom corners will be eased.

For post frame columns above grade, framing or industrial appearance glulams will be most cost effective. Wanting to create some spectacular beamed ceilings or open trusses? If so, architectural or premium appearance might just be your ticket.

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