| Notes to Specifiers: (1) Dry service condition-moisture content of the member will be at
or below 16%in service; wet service condition-moisture content of the member will be above
16% in service. When structural glued laminated timber members are to be preservative
treated, wet-use adhesives must be specified.
(2) An alternative to specifying the required design
stresses is to specify a specific laminating combination symbol if known to be available.
(3)Appearance classifications are described as follows. For
further information, see Engineered Wood Systems Technical Note EWS Y110, Glued Laminated
Timber Appearance Classifications for Construction Applications
FRAMING. The Framing appearance classification is a
new classification introduced by the industry to accommodate home building and other
construction markets where glulam is glued in combination with dimension lumber in roof,
wall and floor framing. To be compatible with the conventional framing lumbers sizes
without the need for furring or other specialized framing, glulam is supplied in 3-1/2,
5-1/2 and 7-1/4-inch widths.
Description: Glulam members manufactured to be compatible
with these dimensions are finished to what are referred to in the industry as "hit or
miss" surfacing. Surface characteristics of glulam members finished to this
classification include:
Manufacturing characteristics including low laminations,
glue smear, end joint offsets and glueline squeeze out are permitted.
Lumber characteristic permitted or the give layup
combination may include knot holes, splits and wane.
Voids appearing on the edge of laminations need not be
filled.
Loose knots and knot holes appearing on the wide face of
the laminations exposed to view need not be filled.
Members are required to be surfaced "hit or miss"
on tow sides only and the appearance requirements apply only to these sides.
Wane (limited to a maximum of 1/4 inch measured across the
width) is permitted on a cumulative basis. The accumulative depth of hit and miss and wane
shall not exceed 10% of the width of the member in any glueline. The frequency of
occurrence shall not exceed one in ten pieces o lumber used. The maximum area of low
laminations shall not exceed 25% of the surface area of side. Permissible wane in
accordance with the provisions of the layup combination is not limited in length.
INDUSTRIAL. Use where appearance is not of primary
importance, or where members are not exposed visually.
Description: Natural lumber growth characteristics may be
visible. Voids on edges of lamination may not be filled in some applications.
ARCHITECTURAL. Use where appearance is important.
Description: Natural lumber growth characteristics may be
visible. Knothole and voids larger than 3/4" are filled or repaired with wood
inserted. Exposed faces are surfaced smooth and exposed edges are eased (chamfered).
PREMIUM. Use where highest-quality visual appearance is
required. |
