The Lapeyre® aluminum alternating tread
stair combines the safety features of our
unique, alternating tread design with the
advantages aluminum has to offer. Aluminum
is ideal for exterior applications and for
applications where weight is a consideration.
The cast aluminum treads are welded to the
central stringer and to the handrails, creating
an all-in-one welded unit.
An optional 3.75" handrail is available for roof
hatch applications.

Example:     8'4-1/4" Stair = $2,876.35
(101" x $23.61) + $492.13 = $2,876.35

Base Price: $701.83 plus $32.07 per vertical inch

3. Always install the stair with the top
tread at same elevation as the upper
finished floor or roof surface. For wall
parapets, contact us.

4. The stair is secured in place by bolts
(not included) at top and bottom.

SECTION 05517 - ALTERNATING TREAD STEEL STAIRS
PART 1 - GENERAL
1.1 RELATED DOCUMENTS:
Drawings and general provisions of Contract, including General
and Supplementary Conditions and Division-1 Specification
sections, apply to work of this section.
1.2 SUMMARY:
A. Provide all material, labor, equipment and services and perform
all operations necessary or required for the work of this section,
in accordance with the Drawings and Specifications, and including fabrication and installation of Alternating Tread Steel Stairs.
B. Related work specified elsewhere includes but is not limited to:
1. Conventional Metal Stairs in another Division 5 section
2. Metal Fabrications in another Division 5 section
3. Painting in Division 9
1.3 PERFORMANCE REQUIREMENTS:
A. Stair Treads: shall be capable of withstanding a single
concentrated 1000 pound load without permanent deformation.
B. Handrail: shall be capable of withstanding a single
concentrated load of 200 pounds or a uniform load of 50 pounds
per linear foot applied in any direction at any point on the rail.
1.4 CONSTRUCTION REQUIREMENTS:
A. Landings, Treads, and Mounting Base: shall be stamped
and formed from single piece material. Stock shapes, hand forming,
or welded remnants shall not be permitted. All stamped parts
shall have integrally formed rigidizing bends and shall be spot
welded to stringers of like material.
B. Welds: shall be a minimum of 6 welds per tread, and 12 welds
each on the landing and footing. Each weld shall be quality
controlled and be capable of withstanding a minimum of
2800 lbs. in shear.
C. Pedestrian Surfaces: shall be punched through with upset
non-skid openings.
D. Riser Spacing: shall be equally spaced to within 3/16" for
adjacent risers and to within 3/8" for any two non-adjacent
risers on a stair.
E. Handrails: shall be contoured for body guidance and underarm
support and shall be attached to the outside stringers and
landings by bolting.
F. Landing Reinforcement: shall be with minumin .20" (0.51 cm)
steel formed angle notched and punched and factory welded to
the landing at the points of a handrail attachment.
G. Rubber Foot Divider: shall be affixed to the central portion
of the landing. A rubber bumper strip shall be attached or will be
provided for field attaching to the central stringer.
1.5 DIMENSIONS:
A. Stair Angle: [56] or [68] degrees from horizontal as specified
in the drawings.
B. Vertical Drop: the change in elevation, as shown in the drawings,
between the upper finished floor surface where the top landing
will be attached and the lower finished floor surface where the
base of the stair will be secured.
1.6 SUBMITTALS:
Dimensional Prints: shall be submitted for approval prior to
fabrication.
PART 2- PRODUCTS
B. Substitutions will not be considered.
2.2 MATERIALS:
A. Carbon Steel:
1. Treads: 13 Gauge 1010/15 HRPO per ASTM A569
2. Landing & Foot Stampings: 11 Gauge 1010/15 per ASTM A569
3. Stringers:
a. 2" x 1 3/4" x 11 Gauge 1010/15 per ASTM A569 for 56 degree
stairs under 10 vertical feet and for 68 degree stairs under 12
vertical feet.
b. 3" x 1 3/4" x 11 Gauge 1010/15 for 56 degree stairs over 10
vertical feet and for 68 degree stairs over 12 vertical feet.
4. Handrails: 1 1/2" OD x 0.083" 1010/15 CS per ASTM A569
cold drawn, fully annealed tube per ASTM 513.
B. Stainless Steel:
1. Treads: 13 Gauge 304 SS
2. Landing & Foot Stampings: 11 Gauge 304 SS
3. Stringers:
a. 2" x 1 3/4" x 11 Gauge 304 SS for 56 degree stairs under 10
vertical feet and for 68 degree stairs under 12 vertical feet.
b. 3" x 1 3/4" x 11 Gauge 304 SS 56 degree for stairs over 10
vertical feet and for 68 degree stairs over 12 vertical feet.
4. Handrails: 1 1/2" OD x 0.065" 304 SS cold drawn, fully
annealed tube per ASTM A513.
C. Miscellaneous Material:
1. Rubber Spine: Hollow neoprene
2. Rubber Foot Divider: Solid neoprene
2.3 FINISHES:
A. Carbon Steel:
1. Safety Yellow Paint: Powder Coat Baked Enamel or
2. Hot-Dip Galvanized: per ASTM A123
B. Stainless Steel: Natural finish
2.4 FABRICATION:
General: Fabricate alternating tread steel
stairs to conform with performance and construction
requirements, and in accordance with approved shop drawings
or dimensional prints. Fabricate and shop-assemble to greatest
extent possible.
A. Carbon Steel: gas metal arc welded with treads spot welded to stringers and bolt-on handrails with included bolts using the
specified materials.
B. Stainless Steel: gas tungsten arc welded and/or gas metal
arc welded with treads spot welded to stringers and bolt-on
handrails with included bolts using the specified materials.
PART 3- EXECUTION:
3.1 PREPARATIONS:
A. Coordination: Coordinate start and installation of steel
alternating treads with all other related and adjacent work.
Installation shall not start until the construction
has progressed to the point that weather conditions and
remaining construction operations will not damage stair
installation.
B. Verification: Verify that dimensions and angle are correct
and that substrate is in proper condition for stair installation.
Do not proceed to install until all necessary corrections have
been made.
3.2 INSTALLATION:
A. If bumper has not been installed at the factory, install the self adhesive bumper.
B. Prepare mounting holes.
C. Position stair with top tread at same elevation as upper
finished floor or roof surface.
D. Secure stair with not less than 2 bolts or studs at top and
with not less than 2 at bottom of stair.
E. Touch up with matching paint any chipped or abraded
damage to factory finish or
F. Touch up any damage to galvanized surfaces using
galvanized repair paint in accordance with ASTM A780.
3.3 CLEAN:
Leave work area clean and free of debris.

SECTION 05 51 6- ALTERNATING TREAD ALUMINUM STAIRS
PART 1- GENERAL
1.1 RELATED DOCUMENTS:
Drawings and general provisions of Contract, including General
and Supplementary Conditions and Division-1 Specification
sections, apply to work of this section.
1.2 SUMMARY:
A. Provide all material, labor, equipment and services and
perform all operations necessary or required for the work of this section, in accordance with the Drawings and Specifications,
and including fabrication and installation of Alternating Tread
Aluminum Stairs.
B. Related work specified elsewhere includes but is not limited to:
1. Conventional Metal Stairs in another Division 5 section
2. Metal Fabrications in another Division 5 section
1.3 PERFORMANCE REQUIREMENTS:
A. Stair Treads: shall be capable of withstanding a concentrated
1000 pound load without permanent deformation..
B. Handraisl: be capable of withstanding a load of 200 pounds
applied in any direction at any point on the rail.
1.4 CONSTRUCTION REQUIREMENTS:
A. Cast Aluminum Treads, Landings, and Mounting Base: shall be shielded metal arc welded to a single extruded box-like stringer.
B. Tread Castings: shall have integrally cast handrail support arms which are precision machined and welded to continuous aluminum handrails.
C. Pedestrian Surfaces: shall be cast with skid resistant surfaces
and all treads shall have upturned integrally cast skid barriers.
D. Riser Spacing: shall be equally spaced to within 3/16" for
adjacent and to within 3/8" for any two non-adjacent risers on
a stair.
E. Handrails: shall be contoured for body guidance and underarm support, and shall have inclined hand side portions for free
sliding of the hands unimpeded by the handrail supports.
F. Cast Aluminum Foot Divider: shall be an integral part of the
landing and shall form a support for a rubber bumper strip that
shall be attached to the central stringer.
1.5 DIMENSIONS:
A. Stair Angle: 68 degrees from horizontal
B. Vertical Drop: the change in elevation, as shown in the
drawings, between the upper finished floor surface where the
top landing will be attached and the lower finished floor surface
where the foot of the stair will be secured.
1.6 SUBMITTALS:
Dimensional prints shall be submitted for approval prior
to fabrication.
PART 2-PRODUCTS
B. Substitutions will not be considered.
2.2 MATERIALS:
A. Landings, Treads and Foot Castings: Aluminum alloy F356F
B. Handrails:
1. Aluminum Alloy 6063-T4 per ASTM B221
2. 1-1/2" x 1/8" Tube
C. Central Stringer:
1. Aluminum Alloy 6063-T52 per ASTM B221
2. 1-3/4" x 4" x 1/8" Box Shape
D. Miscellaneous Materials:
1. Rubber Spine: Hollow neoprene strip
2.3 FINISH: Natural Finish
2.4 FABRICATION:
A. General: Fabricate alternating tread aluminum stairs to
conform with performance and construction requirements,
and in accordance with approved shop drawings or
dimensional prints. Fabricate and shop-assemble to greatest
extent possible.
B. Fabricate gas metal arc welded and/or gas tungsten arc welded alternating tread aluminum stairs using the specified materials.
PART 3- EXECUTION:
3.1 PREPARATIONS:
A. Coordination: Coordinate start and installation of aluminum alternating treads with all other related and adjacent work.
Installation shall not start until the construction has progressed
to the point that weather conditions and remaining construction
operations will not damage stair installation.
B. Verification: Verify that dimensions and angle are correct and
that substrate is in proper condition for stair installation. Do not
proceed to install until all necessary corrections have been made.
3.2 INSTALLATION:
A. Prepare mounting holes.
B. Position stair with top tread at same elevation as upper
finished floor or roof surface.
C. Secure stair with not less than 2 bolts or studs at top and
with not less than 2 at bottom of stair.
3.3 CLEAN:
Leave work areas clean and free of debris.