Section 27-617
§ 27-617 General requirements. Materials (other than non-stress grade
lumber), design, and construction methods shall meet the requirements of
the following reference standards:
(a) Lumber and timber. Reference standard RS 10-8.
(b) Plywood. Reference standard RS 10-9.
(c) Structural glued--laminated lumber. Reference standard RS 10-18.
Section 27-618
§ 27-618 Identification. Except as provided for in subdivisions (a)
and (c) of this section, all wood used for structural elements shall be
identified as to grade and shall bear an identifying mark of an approved
bureau or agency performing the grading, or the official grade mark and
trade mark of the bureau or association under whose rules the wood was
graded, in accordance with the following:
(a) Lumber and timber. All lumber and timber, including non-stress
grade lumber, shall be identified by the grade mark of a lumber grading
or inspection bureau or agency approved by the commissioner, except that
pre-cut material and rough-sawn lumber may be covered by a certificate
of inspection issued by a lumber grading or inspection agency approved
by the commissioner in lieu of grade marking.
(b) Plywood. Plywood used structurally shall bear identification as to
grade, type, and species group, or identification index. Such
identification shall be affixed by and identified by the trademarks of a
testing and grading agency approved by the commissioner.
(c) Glued-laminated. Glued-laminated structural members shall bear
identification and/or shall be accompanied by certification in
accordance with the provisions of reference standard RS 10-18.
(d) Resawn lumber. Resawn (or reused) lumber shall be marked in
accordance with its regraded status.
Section 27-619
§ 27-619 Use of non-stress grade wood. The use of non-stress grade
wood in structural elements shall be limited to the following
conditions:
(a) Studs, joists, and rafters proportioned on the basis of the
empirical provisions of section 27-622 of this article.
(b) The architect or engineer responsible for the design may assign an
allowable stress value for the proposed material based on the provisions
of reference standard RS 10-8 relating to "other species and grade".
Under such condition, the required species and grade of wood, together
with the assigned stress value, shall be conspicuously indicated on the
plans.
Section 27-620
§ 27-620 Quality control. Inspection of the fabrication of
glued-laminated assemblies, as stipulated in table 10-2, shall include a
check of sizes of members, of fit, and of gluing operations.
Section 27-621
§ 27-621 General construction requirements. The provisions of this
section shall be considered as supplemental to the provisions of the
applicable reference standards.
(a) Firecutting. The ends of wood beams, joists, and rafters resting
on masonry or concrete walls shall be firecut to a bevel of three inches
in their depth.
(b) Protection of members.
(1) Positive drainage shall be provided for all areas under the
building not occupied by basements or cellars.
(2) All loose wood and debris and all wood forms shall be removed from
spaces under the building. All stumps and roots shall be grubbed to a
minimum depth of twelve inches.
(3) Wood members embedded in the ground and used for the support of
buildings shall be treated.
(4) Wood joists or wood structural floors closer than eighteen inches,
wood girders closer than twelve inches, or sills closer than eight
inches to an exposed ground surface within or without the building shall
be treated or shall be of an equivalent resistant species.
(5) Sleepers, sills, columns, and posts supported on concrete or
masonry piers shall be treated or shall be of an equivalent resistant
species unless isolated from the ground as specified in paragraph four
of this subdivision or by a concrete slab. Where the isolation consists
of a concrete slab-on-grade, the sleepers, sills, columns, or posts
shall be raised at least three inches above the top of such slab.
(6) Ends of wood girders entering masonry or concrete walls shall be
provided with a minimum one-half inch air space on top, sides, and at
the end, unless the girder is treated or is of an equivalent resistant
species.
(7) Wood or plywood used as siding or a combination of siding and
sheathing shall be isolated from exposed ground by at least six inches.
(8) Crawl spaces shall be ventilated as required in subchapter twelve
of this chapter.
(9) Where treated timber is required, the preservative treatment shall
comply with reference standards RS 10-20 and RS 10-22. Treatment of wood
poles shall comply with reference standard RS 10-28. All treated wood
shall be handled in accordance with the provisions of reference standard
RS 10-29.
Section 27-622
§ 27-622 Empirical provisions in lieu of design. The provisions of
this section may be used in lieu of structural analysis only for those
buildings in occupancy group J-3 where the specific occupancies
correspond to a live load requirement of forty psf, or less, and to
constructions wherein the supporting framing consists of multiple,
closely spaced members, such as joists, studs, platform or balloon
frames. All wood structural members in other classes of construction
shall be proportioned on the basis of the analysis of stresses. All
requirements established in this section may be reduced when an analysis
of stresses, executed in accordance with reference standard RS 10-8,
indicates such reduction is feasible. Sizes of wood members stated in
this section are nominal sizes.
(a) Stud walls and partitions.
(1) Studs shall be of equivalent or better grade than the minimum
grades for the various species as established in reference standard RS
10-13.
(2) Corner posts shall be 3-stud members or members of equivalent
strength.
(3) Load bearing studs shall be set with the larger cross section
dimension perpendicular to the wall or partition. Studs in exterior
walls of one story buildings of construction class II-D and II-E shall
be at least two inches by three inches spaced not more than sixteen
inches on center, or where studs are two inches by four inches, spaced
not more than twenty-four inches on center. Studs for other classes of
construction shall be at least two inches by four inches spaced not more
than sixteen inches on center.
(4) Stud walls resting on concrete or masonry shall have sills at
least two inches in nominal thickness. Where such sills bear on
concrete, they shall be fastened with minimum one-half inch bolts
embedded at least six inches. Each sill piece shall have at least two
anchor bolts, with one bolt located at least one inch from each end of
the plate, and with intermediate spacing not more than eight feet. Where
such sills bear on masonry, they shall be anchored in accordance with
the applicable provisions of reference standard RS 10-1.
(5) Stud partitions that rest directly over each other and are not
parallel to floor joists or beams may extend down between the joists and
rest on the top plate of the partition, partition girder, or foundation
below, or may be constructed on sill plates running on top of the beams
or joists.
(6) All load bearing stud partitions shall be supported on walls,
other partitions, double joists or beams, solid bridging, or on beams at
least as wide as the studs. Joists supporting a partition parallel to
the joists wherein the joists are spaced apart to permit the passage of
piping or duct work shall be provided with solid blocking at intervals
of not more than sixteen inches.
(7) Load bearing partitions perpendicular to joists shall not be
offset from supporting girders, walls or partitions by more than the
depth of the joists unless the joists are proportioned on the basis of
analysis of stress.
(8) In interior walls and in bearing partitions, double studs shall be
provided at the sides of openings that are greater than three feet six
inches up to six feet in width, and triple-studs shall be provided at
the sides of openings of greater width.
(9) Headers shall be provided over each opening in exterior walls and
bearing partitions. Where the opening does not exceed three feet, each
end of the header shall be supported on a stud or framing anchor. Where
the opening exceeds three feet in width each end of the header shall be
supported on one stud and where the opening exceeds six feet each end
shall be supported on two studs.
(10) All studs in exterior walls and in bearing partitions shall be
capped with double top plates installed to provide overlapping at
corners and at intersections with other walls and bearing partitions.
End joists in double top plates shall be offset at least twenty-four
inches. In lieu of double top plates, a continuous header of similar
dimensions may be used. For platform frame construction, studs shall
rest on a single bottom plate.
(b) Bracing of exterior walls. Exterior stud walls shall be braced by
one inch by four inch continuous diagonal strips let into the face of
the studs and into the top and bottom plates at each corner of the
building. Bracing may also be provided by one of the following means:
(1) Wood board sheathing of one inch nominal thickness, applied
diagonally.
(2) For one and two-story dwellings, plywood sheathing at least four
feet by eight feet (except where cut to fit around openings and for
similar purposes) and at least five-sixteenths of an inch thick on studs
spaced sixteen inches or less on centers and at least three-eighths of
an inch thick on studs spaced more than sixteen inches but not exceeding
twenty-four inches on centers.
(3) For one story dwellings and for the upper story of two story
dwellings, fiberboard sheathing applied vertically in panels at least
four feet by eight feet (except where cut to fit around openings and for
similar purposes). Fiberboard sheathing shall be at least one-half inch
thick and shall conform to the provisions of reference standard RS
10-27.
(4) For one story dwellings and for the upper story of two story
dwellings, gypsum board sheathing applied horizontally in panels at
least two feet by eight feet (except where cut to fit around openings
and for similar purposes). Gypsum boards shall be at least one-half inch
thick and shall conform to the provisions of reference standard RS
10-19.
(c) Floor and roof framing.
(1) SPAN TABLES. Joists and rafters may be used in accordance with
reference standard RS 10-13.
(2) BRIDGING. In all floor and roof and roof framing, there shall be
at least one line of bridging for each eight feet of span. The bridging
shall consist of at least one inch by three inch lumber or equivalent
metal bracing. A line of bridging or solid blocking shall also be
required at supports unless lateral support is provided by nailing to a
beam, header, or to the studs. Midspan bridging is not required for
floor or roof framing in one- and two-family dwellings where joist depth
does not exceed twelve inches. Bridging shall bear securely against and
be anchored to the members to be braced.
(3) NOTCHES. Notches in the ends of joists and rafters shall not
exceed one-fourth the depth unless adequate reinforcement is provided or
analysis of stresses indicates that larger openings are feasible without
the necessity for reinforcement. Notches in joists or rafters, located
in the span shall not exceed one-sixth the depth and shall not be
located in the middle third of the span. Bored holes shall not be within
two inches of the top or bottom of the joists or rafter and the diameter
of any such hole shall not exceed one-third the depth. For stair
stringers, the minimum effective depth of the wood at any notch shall be
three and one-half inches unless the stringer is continuously supported
on a wall or partition.
(4) SUPPORT.
a. Floor or roof framing may be supported on stud partitions.
b. Tail beams over twelve feet long and all header and trimmer beams
over six feet long shall be hung in metal stirrups having anchors, or by
other methods providing adequate support. Trimmers and headers shall be
doubled where the header is four feet or more in length.
c. Except where supported on a one inch by four inch ribbon strip and
nailed to the adjoining stud, the ends of floor joists shall have at
least one and one-half inches of bearing on wood or metal, nor less than
four inches on masonry.
d. Joists framing from opposite sides of and supported on a beam,
girder, or partition shall be lapped at least four inches and fastened,
butted end-to-end and tied by metal straps or dogs, or otherwise tied
together in a manner providing adequate support.
e. Joists framing into the side of a wood girder shall be supported by
framing anchors, on ledger strips at least two inches by two inches, or
by equivalent methods.
f. Wood joists and rafters bearing on masonry walls shall be anchored
to such walls in accordance with the applicable provisions of reference
standard RS 10-1.
(5) RAFTERS AND CEILING JOISTS.
a. Where rafters meet to form a ridge, they shall be placed directly
opposite each other and nailed to a ridge board at least one inch thick,
and not less than the cut end of the rafters in depth.
b. Provisions shall be made to resist the thrust from inclined rafters
by connection of collar beams at least one inch by six inches, by
connection to joists, or by equivalent means.
c. Where ceiling joists are not parallel to rafters, subflooring or
metal straps attached to the ends of the rafters shall be installed in a
manner to provide a continuous tie across the building.
d. Ceiling joists shall be continuous, or where they meet over
interior partitions, shall be securely joined to provide a continuous
tie across the building.
e. Valley rafters shall be double members. Hip rafters may be single
members. Valley and hip rafters shall be two inches deeper than jack
rafters.
f. Trussed rafters shall be designed in accordance with the provisions
of reference standard RS 10-8.
(6) Built-up members shall be securely spiked or bolted together and
provision shall be made to resist the horizontal shear between
laminations.
(d) Nailing schedule. The size and number of nails for connections
shall be in accordance with table 10-4.
Section 27-623
§ 27-623 Heavy timber construction (construction class II-A). (a)
Minimum sizes of members. To conform to the fire resistance rating
requirements for heavy timber construction (construction class II-A),
members shall be solid sawn or solid glue-laminated and of the following
minimum dimensions: (Sizes of wood members indicated in this section are
nominal sizes).
(1) COLUMNS, FRAMES AND ARCHES.
a. Columns shall be at least eight inches in all dimensions when
supporting floor loads, and at least six inches wide and eight inches
deep when supporting roof and ceiling loads only.
b. Beams and girders shall be at least six inches wide and ten inches
deep.
c. Frames or arches that spring from grade or the floor line and
support floor loads shall be at least eight inches in all dimensions.
d. Timber trusses supporting floor loads shall have members at least
eight inches in all dimensions.
e. Frames or arches for roof construction that spring from grade or
the floor line and do not support floor loads shall have members at
least six inches wide and eight inches deep for the lower half of the
height, and at least six inches deep for the upper half.
f. Frames or arches for roof construction that spring from the top of
walls or wall abutments, framed timber trusses, and other roof framing,
which do not support floor loads, shall have members at least four
inches wide and six inches deep. Spaced members may be composed of two
or more pieces at least three inches thick when blocked solidly through
their intervening spaces or when such spaces are tightly closed by a
continuous wood cover plate at least two inches thick secured to the
underside of the members. Splice plates shall be at least three inches
thick. When protected by approved automatic sprinklers under the roof
deck, framing members shall be at least three inches wide.
(2) FLOORS.
a. Planks shall be splined or tongue-and-groove, not less than three
inches thick, covered with one inch tongue-and-groove flooring, laid
crosswise or diagonally to the plank, or other surface having equivalent
fire resistance; or shall be,
b. At least four inches wide, set on edge close together and well
spiked, and covered the same as for three inch thick plank. The planks
shall be laid so that there is no continuous line of end joints except
at points of support. Floors shall not extend closer than one-half inch
to walls to provide an expansion joint, but the joint shall be covered
at top or bottom to avoid flue action.
(3) ROOF DECKS. Roof decks shall be splined or tongue-and-groove
planks at least two inches thick; or tongue-and-groove plywood panels
(bonded with exterior glue) at least one and one-eighth inch thick, with
face grain perpendicular to supports that shall be spaced not more than
forty-eight inches on center; or of planks at least three inches wide
set on edge close together and laid as required for floors.
(b) Construction details. Self releasing type wall plate boxes or
approved hangers shall be provided where beams and girders enter
masonry.
(For Table 10-4 see chapter 839 of the laws of 1986)
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Section 27-624
§ 27-624 Construction methods. (a) Fabrication. All timber shall be
accurately cut and framed to a close fit in such a manner that the
joints will have even bearing over the contact surfaces. Mortises shall
be true to size for their full depth and tenons shall fit snugly. No
shimming in joints, or open joints, shall be permitted.
(b) Erection.
(1) ASSEMBLY. Joints shall have a tight fit. Fasteners shall be
installed in a manner that will not damage the wood. End compression
joints shall be brought to full bearing. All framework shall be carried
up true and plumb.
(2) TEMPORARY CONNECTIONS. As erection progresses, the work shall be
bolted, or nailed as necessary, to resist all dead load, wind, and
erection stresses.
(3) ALIGNMENT. The structure shall be properly aligned before final
tightening of the connections.
To the extent possible under law, Friends of Devin Balkind for Public Advocate has waived all copyright and related or neighboring rights to New York City Administrative Code. This work is published from: United States.
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