Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates. to building deck construction
which may be uti.lized for interior decks and roof decks.
According to the present invention, there i8 provided
a poured building deck structure which includes structural
purlins and sub-purlins o sheet metal structural shapes of a
box section having a horizontal base, opposing vertical sides
and upper horizontal flanges extending inwardly from the top
of the sides forming an open slot b~tween the terminus of
the ~langes, the sub-purlins being at right angles to the base
resting on top of the purlins. Formboard is provided adjacent
to and secured against the top of the upper horizontal flanges
of the sub-purlins. Sheet metal clips are provided wh.ich have
a vertical portion extending upwardly and downwardly from
opposing slots, each of the opposing slots engaging one of the
horizontal flanges of the box section when the axis of the clip
and the box section are at about 90 to each other, the upwardly
extending vertical portion bending to a horlzontal portion to
engage the top of the formboard securing it against the top of
the flanges, then bending to a substantially vertical upward
portion and then bending to a substantially horizontal portion
to provide uplift resistance when surrounded by concrete.
Over the top of the clips, reinforcing mesh is provided, and
concrete is poured above the formboard and engages the upper
portion of the clips.
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It may be seen, therefore, that deck construction
of this invention utilizes sub-purlin.s formed from sheet metal
and clips formed from sheet metal to provide a deck construction
system which is extremely versatile. The deck structures of
this invention are generally poured gypsum or other poured
concrete-like deck systems wherein rigid formboard is laid on
the sheet metal structural shape sub-purlin and held in place
by the sheet metal clips. The sheet metal clips further provide
uplift resistance to the composite structure. The deck
construction of this invention also provides for insulAted decks
of varying insulation capabilities. The utilization o~ the sheet
metal sub~purlins in the deck construction of this invention
allows utilization of various spacings of the sub-purlins and
various thicknesses and sizes o the formboard. ~he deck
construction of this invention further provides for utilization
of both moisture permeable and moisture impermeable formboards.
The sheet metal sub-purlin shapes utilized in this
invention have previously been used with similax sheet metal
clips for holding tongue and groove precast deck planks such
as sold under the
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trademark TECTUM by National ~ypsum Company. Ilowever,
the utilization of a similar sub-purlin and sheet
metal clip has not been recognized as advantageous
in poured deck construction. Conventional poured deck
construction utilizes bulb tees or truss tees as sub-
purlins. Both the bulb tees and truss tees have
upstanding portions which govern the spacing due to
the projection into the poured gypsum or concrete in
an attempt to obtain resistance to uplift. It has been
recognized that poured decks utilizing bulb tees as
sub-purlins must be used only with moisture permeable
formboard and that top drying with ventilators has
been unsatisfactory where the bulb tee extends into
the poured material.
The deck construction of this invention
provides a method of construction in which the sub-
purlin is flat on top and is totally beneath the
deck structure, thus, providing a framework in which
the sub-purlins may be placed at any desired spacing
to obtain various strength characteristics and the
deck structure is placed on top of the flat upper
surface or the sub-purlin. Uplift resistance is
obtained by the sheet metal clip extending into the
poured structure.
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It is an object of this invention to over-
come the above disadvantages of prior deck construction.
It is another object of this invention to
provide deck construction utili~ing sheet metal
sub-purlins which are totally beneath the poured deck
- structure and sheet metal c~ips which readily attach
to the sheet metal sub-purlins and extend into the
poured deck structure to provide excellent uplift
resistance.
It is a further object of this invention to
provide deck systems which are extremely flexible
- with respect to sub-purlin spacing to obtain a wide
range of strength characteristics.
It is still another object of this invention
to provide an economical, insulating and fireproof
poured gypsum roof deck system.
It is another object of this invention to
provide a deck structure which has continuous and full
insulation, thereby overcoming moisture problems
encountered with partially insulated systems.
These and other objects, advantages and
features of this invention will be apparent from the
description and by reference to the drawings wherein
preferred embodiments are shown as:
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Fig. 1 is a perspective cutaway view of a
deck construction according to one embodiment of this
invention;
Fig. 2 is a sectional view of the deck
construction shown in Fig. l; and
~ ig. 3 is a perspective cutaway view of an
insulated roofing structure according to one preferred
embodiment of this invention.
The sheet metal structural shape utilized
in this invention provides excellent structural
characteristics while reducing weight and providing
a structural shape that can be readily fabricated from
sheet metal. To obtain comparable structural strength
characteristics the sheet metal shape used in this
invention is about forty percent lighter than the bulb
tee section required. It is highly desirable to
f~bricate structural shapes from sheet metal to
minimize energy requirements in production and to
conserve steel. Prior attempts to utilize sheet metal
shapes in poured deck constr~ction have not been entirely
satisfactory. Some prior attempts have utilized
sheet metal ~ shapes as substitutes for bulb tees in
roof deck construction. Some of these sheet metal
~ shapes while providing sufEicient strength in the
composite assembled poured roof, do not have satis-
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factory stren~th characteristics themselves ind
in the erection bend over or roll when walked upon
by the erectors. This results in very dangerous
worlcing conditions for workers.
The sheet metal structural shapes utilized
in this invention provide desirable strength
characteristics themselves and sufficient strength
characteristics to be walked upon during erection
without dangerous bending or rolling. Further, the
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sheet metal sub-purlins utilized in the deck
construction o~ this invention provide a flat
upper surface upon which the base material for the
deck construction may be laid. All prior sub-purlins
known to the inventor utilized in poured deck con-
struction, have extended into the poured structure
and thus the spacing of the sub-purlins has been
governed by the width of formboard or rigid board
material laid between them. In the deck construction of
this invention, the rigid board, such as formboard,
is laid on top of the sub-purlin and thus, the
sub-purlins may be utilized in closer spacing allowing
thinner formboards and poured decks to be placed on
top of the closer spaced sub-purlin structure.
Previously, design of deck construction of the poured type
h-s been limited by width of boards available which
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govern the spacing of the sub~purlins since the boards
had to be set between the sub-purlins. The deck
construction of this in~ention allows the use of
any width or length board to be placed ~pon the top
surface of any desired spacing of sub-purlins
Referring to Fig. 1, the sheet metal shape
utilized in this invent:ion is shown as box section
20 having a lower horizontal base 21 resting upon
purlin structure 30, vertical sides 22 and 23 and
upper horizontal flanges 24 and 25. Slot 26 between
the terminal ends of flanges 24 and 25 is preferred
to be continuous to permit the most flexible use of
the sheet metal box section. However, it is under-
stood that slot 26 may be discontinuous and flanges
2S and 25 joining to enclose the top of the box
section where it is not necessary to utilize the
sheet metal clips.
The Fheet metal box sections may be fabri-
cated by well-known roll forming techniques from
sheet metal from about 20 gauge to about 14 gauge.
It is preferred to use galvanized, commercial grade
steel o 16 and 18 gauge.
The depth of the box section to` be used
as a sub-purlin may be about 2 inches to about 3
inches, preferably about 2-1/4 inches to about 2-1/2
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inches. 'rhe width of the box section may be about
1-l/2 inch to about 2-1/2 inches, preferably abollt
1-3/4 inch to ~bout 2 inches. The slot for receiving
the sheet l~etal clip may be any width to suit the -
clip section. Slots about 3/8 inch to about 3/4 inch
are suitable, about 5/8 inch being preferred. It
should be recognized that the above dimensions are
governed only by conventionally desired strength
characteristics of described uses as sub-purlins
and may be outside the above ranges to obtain out-of-
the ordinary requirements.
The sheet metal clip is shown as 40 having
opposing slots 42 between vertical portion 41 and 43
which engage flanges 24 and 25 of the sheet metal box
~ection so that when the axis of the clip is 90~
with the axis of the box section, the clip is anchored
with the opposing flanges of the top of the box
section engaging the slots and vertical portion 41
being within the box section. Vertical portion 43
of the sheet metal clip extends upward from the top
of the box section a suitable height to provide,
when bent into horizontal portion 44, snug fitting
of desired rigid board such as formboard 12
between horizontal portion 44 and the top flanges
24 and 25 of the sheet metal box section. Horizontal
portion 44 extends a sufficient distance to provide
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such snug fitting and then bends to form vertical
portion 45 which extends substantially vertically upward
for the desired distance to provide a support for rein-
forcing mesh 14. The sheet metal Slip is then provided
with substantially horizontal portion 46 which holds the
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reinforcing mesh 14 and provides for uplift resistance
in the poured deck.
Clip 40 is readily inserted at any location
into slot 26 by simply turning it so that the axis
of the clip and the box section are parallel and
inserting the clip for the distance so that slot 42
will engage flanges 24 and 25 and then turning the
clip so that axis of the clip is approximately 90
to the axis of the sub-purlin.
The sheet metal clips may be fabricated
by well known stamping and bending techniques from
sheet metal from about 20 gauge to about 14 gauge.
It is preferred to used galvanized, commercial steel
of 16 and 18 gauge.
The vertical portion of the clip extending
above the box section may be about 1/2 to about 1-1/2
inch to accommodate the thickness of various desired
formboards.- The vertical portion of the clip
extending into the sheet metal box section may be any
desired length so as to provide adequate stiffness
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of the clip when the flanges of the box section are
engaged in the opposing slots of the clip. ~lori~ontal
portion 44 of the clip extends for a suitable distance
to adequately hold the formboard in place, about 1/2
to about 1 inch being suitable. Vertical portion 45
extends upward for a suitable distance to provide
support for reinforcing mesh and to provide suitable
height for the poured concrete to firmly engage the
clip for uplift res,istance about 1/2 to about 1-1/2
inch being suitable. Horizontal portion 46 is of
suitable length to provide firm clipping of the poured
concrete to provide for uplift resis~ance about l/2
to about 1-1/2 inch being suitable.
Referring to Fig. 3~ the sheet metal box
section sub-purlin 20 rests upon structural purlin
member 30 and clip 40 secores gypsum formboard against
the top ,of sub-purlin 20. Over formboard 12 is a
polymeric foam board 18 having seams at right angles
to the seams of formboard 12. It is preferred to
staple the foam in place to prevent uplift whlle
pouring cement,as indicated by staples 51. The foam
board may also be adhered to the formboard with any '
suitable mastic or adhesive. 'The Eoam is brolcen
out in the area o each clip 40 so that the
poured concrete surrounds the top of the clip to
provide uplift resistance. A poured gypsum or light-
weight concrete is applied above the foam board
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with reinforcing mesh 14, gypsum concrete 15 with
built-up roofing layers 16 and wear surface 17.
This type of gypsum structure may be dried from
the top using ventilators shown as 19 and presently
available as McKinley Roof Ventilators. This
structure provides a primarily top drying system
allowing the use of moisture impervious formboards.
The synthetic organic polymer foam may be
any substantially rigid organic polymer foam having
good insulating properties and preferably a high
temperature at which thermal decomposition occurs.
Suitable foams include polystyrene, styrene-maleic
anhydride, phenolic, such as phenol formaldehyde,
polyurethane, vinyl, such as polyvinyl chloride and
copolymers of polyvinyl chloride and polyvinyl
acetate, epoxy, polyethylene, urea formaldehyde,
acrylic, polisocyanurate and the like. Preferred
foams are selected from the group consisting of
polystyrene and polyurethane. Particularly suitable
foams are closed cell foams which provide high
insulating properties and low internal permeability
to moisture. S-uch organic polymer foams are substan-
tially rigid bodies of foam and are well known for
their low density and outstanding thermal insulating
properties. The foam is preferably in boa:d form
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and may be utilized in sheets of any workable size. It i~
preferred to have the foam board at right angles to the form-
board to minimi~e seam exposure. Any thickness providing
desired insulation is suitable, about 1 inch to about 6 inches
being preferred and about 1 inch to ~bout 3 inches being
especially preferred.
~he gypsum formboard~foam structure as disclosed in
my U.S. Patent 3,965,641, issued June 29, 1976, may advantage-
ously be ~sed in the roof structure of this invention, per-
mitting complete flexibility with respect to sub-purlin spacing~
Likewise, the gypsum formboard-foam construction disclosed in
my Canadian Patent No~ 1,002,722, January 4r 1977 may be
utilized in a similar fashion without the need for ventilator
- 19 since the roof structure disclosed in my Canadian Patent
No. 1,002,722 provides for drying of the gypsum concrete
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through the bottom of the roof. Further, the deck construction
of this invention eliminates the need for grouting as shown in
my above identified co-pending applications and provides for
full, continuous insulation.
Any moisture permeable or molsture impervious form-
board of a wide variety of sizes may be used in the deck
construction of this inventlon. ~he structure of this invention
allows the use of less expensive
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water impervious ~ormboard such as felted rock
wool materials tSUch as FESC0 board sold by Johns
Manfille Company). Any gypsum formboard, moisture
permeable or moisture impermeable,.fiberglas or
other conventional formboard material is suitable.
~ormboard thickness of about 114 inch to about 2
inches are suitable, about 3/8 inch to about 3/4
inch being preferred. The sub-purlin system with
~ormboard at right angles to the sub-purlines
prevents formboard fall-out and undesired deflection
experienced with bulb tee and truss tee sy$tems now
used.
Any gypsum formboard providing a two hour
fire rating when used with poured gypsum slabs is
~specially suitable. The least expensive of the
gypsum formboards, the rigid 1/2 inch thick gypsum
~ormboard is suitable for use in the roof structure
of this invention, however, various surfaced gypsum
~ormboards having suitable ceiling surfaces may be
utilized as long as the incombustibility and flame
spread rat-ings are satisfactory. This invention
provides a deck structure in which gypsum formboard
may be used as the lower surface.
Previously, lightweight concrete has been
poured over galvanized pans rather than formboard
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since using conventional bulb tee construc~ion
which was limited to 32 inch spacing, the gypswn
formboard buckled when wet due to the long drying
time of lightweight concrete. In.view of the
structural flexibility of the deck structure of this
invention, the sub-purlins may be spaced about 12 to
about 36 inches providing a superior base for the
gypsum formboard and prevention of such previous
buckling. Thus, the poured structure shown as 15
in Figs. 1 and 2 may satisfactorily be lightweight
concrete.
According to present deck construction
practice utilizing bulb tee or truss tee sub-purlins
with the concomitant spacing of 32 inches, it has not
been practical to provide gypsum slabs of less than
2 inches. Previously, it was necessary to have a
slab thickness of about 2 inches to cover the upstanding
bulb or truss tee. Utilizing the roof structure of
this invention, it is practical to use gypsum slabs
as thin as about 1 inch by having close sub~purlin
spacing. This deck construction provldes lighter
weight decks.
The gypsum concrete utilized may be preferably
standard gypsum concrete. Ho~ever, modified concretes
containing various fillers, such as perlite, aggregate
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for thermal insulation and lighter weight are suitable,or exploded mica in portland cement is suitable, but
not necessary in the roo~ structure of this invention.
The gypsum concrete is especially desirable for use in
roof structures not only because it is incombustible
but also because the gypsum sets within a few minutes
to form a slab that is hard enough to walk upon there-
by permitting, in many cases, a waterproof wearing
surface to be laid the same day the slab is poured.
The thickness of the poured concrete may be about l
inch to about 4 inches.
In Fig. l a built up roofing membrane
comprising alternate layers of roofing felt and hot
asphalt is shown as 16 with waterproof wearing
surface 17 oi tar and gravel. Any suitable waterproof
wearing surface for flat type roofs is suitable for
the roof structure of this invention, or the gypsum
concrete may be waterproofed with plastic membrane,
such as on dome type roof structures. Likewise, when
used as an interior deck, the concrete top surface
may be left exposed.
Any suitable ceiling structure may be installed
beneath the deck structure of this invention as long
as suitable ventilation is furnished. However, in
contrast to prior roof struct-1res, it is not necessary
that the ceiling provide the insulation or fireproofing
qualities. The roof structure of this invention
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provides high insulation and fireproof properties
without any structure beneath it and may be left
exposed,
While my invention has been described mainly
with respect to a roof deck system, it is also suitable
and intended for any deck system such as flooring - .
ceiling in multistory construction.
While in the foregoing specification this
invention has been described in relation to certain
preferred embodiments thereof, and many details have
been set forth for purpose of illustration, it will be
apparent to those skilled in the art that the invention
is susceptible to additional embodiments and that
certain of the details described herein can be varied
considerably without departing from the basic
principles ol the invention.
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