ANSI/AWI 1236-2022 - Countertops
3.3 Structural
a) Countertops shall be constructed to resist a 22.7 kg [50 lbs] per 93,025 sq. mm [144 sq. in.] load and not deflect in excess of 6.4 mm [.250”] in any direction. Countertop shall not crack nor be permanently deformed under this load.
b) Load values expressed within this standard do not suggest service loads nor shall they be construed as suggesting normal countertop usage loads.
c) Fittings and fixtures installed in a factory setting shall be mounted in accordance with manufacturer/supplier’s documented instructions.
d) Cut-outs within a countertop shall be made by either manufacturer/supplier or installer. Sink cut-outs shall not fall within 457 mm [18”] of a joint.
3.3.1 Joints
a) Shall be neatly and accurately made.
b) Shall be secure.
3.3.2 Overhangs
a) Shall be consistent, extending a minimum of 12.7 mm [.500”] and a maximum of 31.8 mm [1.250”] over the outermost cabinet face and/or finished end, except at countertops that abut appliances or appliance openings.
b) Shall be parallel with the cabinet face within ± 4.8 mm [.188”] along the entire elevation.
c) Shall be a maximum of 6.4 mm [.250”] where countertops abut appliances or appliance openings.
3.3.3 Suspended or Cantilever Countertops
a) Shall not extend more than 305 mm [12”] from a support (See Figure 50), whether in the front, back, or end, unless otherwise specified.
b) Build-up, when used, shall be full depth at support locations.
3.3.4 Spans
3.3.5 Decorative Laminate
a) Cut-outs shall have a 6.4 mm [.250”] minimum radius.
b) Bottom of edging and its build-up shall be free of dents, torn grain, glue, and shall be sanded smooth with sharp edges removed.
c) Installation joints shall be machined to fit tight and flush, reinforced for alignment, and have provision for draw-bolt-type mechanical fasteners to fasten the joint, if practical.
d) Assembled joints shall be securely attached with glue and with mechanical fasteners. Joints shall fit tight and flush.
e) Shall be securely attached to the core with Type II adhesive applied as recommended by the adhesive manufacturer/supplier. Adhesive for solid color core laminate application shall conform to the manufacturer/supplier’s recommendation.
f) Telegraphing shall not exceed .1 mm [.004”] in any 76.2 mm [3”] span.
g) Sink countertops and their splashes require particleboard or fiberboard with a 24-hour thickness swell factor of 5.5% or less, in accordance with ASTM D1037 (latest edition) or veneer core substrate with Type II adhesive.
h) Factory cut-outs for sinks and other locations subject to excessive moisture shall be sealed with a minimum of one coat of color-tinted (for verification) water-resistant sealer or sealant.
3.3.5.1 Assembly Type 1 - Wall Mount Splash (See Figure 11)
a) Splash components are not required to be factory-mounted.
b) Exposed edges shall be edgebanded.
3.3.5.2 Assembly Type 2 - Countertop Mount Splash (See Figure 12)
a) Butt-joined backsplash components shall be factory-mounted and securely attached with mechanical fasteners.
b) Coved backsplashes shall require a moulded cove stick, continuously glued, with no voids permitted between the decorative laminate or core and the cove stick.
c) End splash components are not required to be factory-mounted with mechanical fasteners.
d) Raw core shall be sealed before assembly at joint between countertop and butt-joined back and end splash components or cove countertop and end splash component.
e) Scribe allowance at splashes shall be provided by manufacturer/supplier per ANSI/AWI 0620 – Finish Carpentry/Installation (latest edition).
f) Exposed edges shall be edgebanded.
3.3.6 Solid Surface
a) Expansion clearances shall be furnished where required by building design or sheet material manufacturer’s recommendations.
b) Seamed joints shall be machined and assembled in accordance with sheet material manufacturer’s recommended seaming procedures.
c) Cut-outs and inside corners shall be radiused in accordance with sheet material manufacturer’s recommendations.
3.3.7 Epoxy Resin
3.3.8 Natural/Engineered Stone
3.3.9 Solid Wood
a) Glue-up requires that the crown of boards be alternated.
b) Installation joints shall be machined to fit tight and flush, reinforced for alignment, and have provision for draw-bolt-type mechanical fasteners to fasten the joint, if practical.
c) Assembled Product joints shall be securely attached with glue and mechanical fasteners. Joints shall fit tight and flush.
d) Factory cut-outs for sinks and other locations subject to excessive moisture shall be sealed with a minimum of one coat of color-tinted (for verification) water-resistant sealer or caulk.
3.3.10 Veneered Wood
a) Sink countertops and their splashes require particleboard or fiberboard with a 24-hour thickness swell factor of 5.5% or less, in accordance with ASTM D1037 (latest edition) or veneer core substrate with Type II adhesive.
b) Telegraphing shall not exceed .1 mm [.004”] in any 76.2 mm [3”] span.
c) Factory cut-outs for sinks and other locations subject to excessive moisture shall be sealed with a minimum of one coat of color-tinted (for verification) water-resistant sealer or caulk.
3.3.11 Solid Phenolic
a) Seamed joints shall be machined and assembled in accordance with sheet material manufacturer’s recommended seaming procedures.