Note: Descriptions are shown in the official language in which they were submitted.
CA 02444337 2003-10-03
FIREIPARTY WALL SYSTEM
TECHNICAL FIELD
[0001] The present invention relates to multi-unit dwelling construction in
general
and in particular to party walls separating adjacent units of a multi-unit
dwelling.
BACKGROUND
(0002] Multi-unit residential buildings have been constructed for many years,
and
employ a wide variety of architectures and methods of construction. Typically,
in one
of the most common constructions, the multi-unit buildings comprise a series
of units
disposed side-by-side. Adjacent units share a common wall known in the art as
a
party wall or a fire wall, hereinafter referred to as a party wall. Interior
units have two
party walls, one on each side, while each end unit has only one party wall
shared with
the next most proximate interior unit. Building codes commonly include special
construction requirements for party walls which insure a specified degree of
fire
resistance, usually specified in terms of hours. In order to obtain the
required fire
resistance, prior party walls have been constructed of fire-resistant
materials such as
concrete block, brick, cinderblock, gypsum board or a combination of like
materials.
[0003] An additional requirement of party walls is sound resistance. Families
and
occupants of individual units generate a certain degree of noise during their
daily
living routines, and also when entertaining guests during special occasions.
Typically,
the occupants of adjacent units do not celebrate or entertain at the same
time, thus to
prevent disrupting the privacy and quiet enjoyment of occupants, it is highly
desirable
to not transmit sounds between units. Building codes also typically require a
minimum degree of sound impedance through a party wall.
[0004] The construction of the mufti-unit residential buildings can be
performed
in a serial manner in which an end unit is first constructed, then each
subsequent unit
is built to an end of the preceding unit with the shared party wall
constructed in turn.
In an alternative method of construction, the individual units can be
simultaneously
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constructed at the same time, or construction can start with an interior unit
with
subsequent units being added to each side thereof wherein the party walls are
constructed as each unit progresses. Construction in this manner is
inefficient because
it requires scheduling various skilled trades in a particular order. For
example, if the
units are built serially as described above, the basic residential unit can be
of typical
wood construction requiring carpenters for the initial framing before a first
party wall
can be built. When the construction reaches the point of building the party
wall, the
carpenters yield to such skills as masons for the construction of a concrete
block party
wall. When the party wall is complete the carpenters return for framing the
next unit
and continue alternating with the masons until all units are built. As one can
readily
see, this is an inefficient utilization of an increasingly expensive labor
force.
[0005] Previous methods of party wall construction using blocks or bricks are
labor intensive and require skilled, on-site labor. These drawbacks have given
rise to
the prefabricated party wall industry. Prefabricated party walls typically
include a
frame that is covered with fire-resistant sheets on both sides and filled
therebetween
with an acoustic insulation. Although this construction approach is more
efficient
than on-site construction, it is still labor intensive.
[0006] Therefore, there is a need in the industry for a modular party wall
that
utilizes minimum skilled labor and provides increased fire resistance and
reduced
acoustic transmission between adjacent residential units of a mufti-unit
building.
SUMMARY OF THE INVENTION
[0007] One aspect of the present invention is directed to a party wall system
for
installation between adjacent units of a mufti-unit residential dwelling. The
party wall
system comprises at least one party wall panel having a foam core, at least
one
structural stud partially embedded in a first face of the core and at least
one structural
stud partially embedded in a second face of the core, and a concrete member
covering
the second face of the core. A fire-resistant sheet is affixed to the
structural stud in
the first face of the core. The fire-resistant sheet is spaced from the first
face and
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defines a first sound channel therebetween. A spacer is affixed to the
structural stud
in the second face of the core and exterior of the concrete member. A fire-
resistant
sheet is affixed to the spacer, and the fire-resistant sheet is thereby spaced
from the
concrete member and defines a sound channel therebetween.
[0008] Another aspect of the present invention is directed to a party wall
panel for
use in a party wall between adjacent units of a mufti-unit residential
dwelling. The
party wall panel comprises a foam core having a first face and a second face.
At least
one structural stud is partially embedded in the first face of the core, and
at least one
structural stud is partially embedded in said second face of said core. A
concrete
member covers the second face of the core.
[0009] Yet another aspect of the present invention is directed to a method of
fabricating a party wall panel for use in constructing a party wall between
adjacent
units of a mufti-unit residential dwelling. The party wall panel is of the
type
comprising a foam core, a plurality of structural studs partially embedded in
a first
face of the core and a plurality of structural studs partially embedded in a
second face
of the core, and a concrete member covering the second face of the core. The
method
comprises a number of steps. First, the structural studs are arranged in a
desired
substantially parallel spaced relationship. Next, a resinous foam is expanded
in a
manner to form a panel core and embed a portion of the studs in a first face
of the core
and embed a portion of the studs in a second face of the core, each stud
having a cap
extending outwardly of either the first or second face of the core. Concrete
is poured
over the second face of the core to form the concrete member with a thickness
substantially equal to the extent of the outward extension of the stud from
the second
face of the core. Finally, the concrete member is cured.
[0010] These and other advantages of the invention will be further understood
and
appreciated by those skilled in the art by reference to the following written
specification, claims and appended drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0011] In the drawings:
[0012] Figure 1 is an exploded isometric view of a multi-unit residential
building
wherein party wall panels according to one embodiment of the present invention
are
placed between adjacent residential units.
[0013] Figure 2 is an elevational cross section of an installed party wall
panel and
supported in place by a footer and the roof structure according to one
embodiment of
the invention.
[0014] Figure 3 is a cross-sectional plan view of an installed party wall
according
to one embodiment of the invention taken along the line 3-3 of Figure 2.
[0015] Figure 4 is an exploded isometric view of an second embodiment of the a
party wall system.
[0016] Figure 5 is a cross-sectional plan view of the party wall module of
Figure 4
taken along the line 5-5.
[0017] Figure 6 is a cross-sectional view of a stud having a void space for
receiving a fastener on a concrete side of the party wall panel.
[0018] Figure 7 is a cross-sectional view of a stud having a foam panel
affixed to
one cap for permitting the receiving of fasteners in the stud cap on the
concrete side of
the party wall panel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] For purposes of description herein, the terms "upper", "lower", "left",
"rear", "right", "front", "vertical", "horizontal", and derivatives thereof
shall relate to
the invention as oriented in Figure 4. However, it is to be understood that
the
invention may assume various alternative orientations and step sequences,
except
where expressly specified to the contrary. It is also to be understood that
the specific
devices and processes illustrated in the attached drawings, and described in
the
following specification, are simply exemplary embodiments of the inventive
concepts
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defined in the appended claims. Hence, specific dimensions and other physical
characteristics relating to the embodiments disclosed herein are not to be
considered
as limiting, unless the claims expressly state otherwise.
[0020] Turning to the drawings, Figures 1-3 illustrate one embodiment of a
party
wall system 20, which in the embodiment shown functions to separate two adj
acent
units 12, 14 of a multi-unit residential building 10. Party wall system 20
provides two
basic functions. First the system 20 provides fire resistance between adjacent
units
12, 14 to delay the progress of a fire from one unit to the next. Second,
party wall
system 20 also provides sound isolation between units so that noise emanating
from
one unit is impeded from traveling to the next unit.
[0021) Party wall system 20, most thoroughly shown in Figure 3, includes as a
central structure, a party wall panel 30. Party wall panel 30 has a central
foam core
32. Foam core 32 can be made from any foam, and it preferably is made from
expandable resinous foam, such as, for example, Expandable Poly Styrene (EPS).
[0022] The foam core 32 has a plurality of structural studs 36, 38 embedded
therein. Studs 36, 38 can be of different configurations, but in the preferred
embodiment, studs 36, 38 are metal C-channels of the type being used as a
replacement for standard wood 2x4's. Studs 36, 38 are arranged in a vertically
parallel fashion and are substantially equally spaced one from the other in
the lateral
direction. Preferably, studs 36 have one of their caps 37 extending from a
first face 34
anywhere between one-eighth inch and two inches, and most preferably one-half
inch.
[0023] Studs 38 are embedded in foam core 32 and extend through a second face
33. A concrete member 44 covers a second face 33 of foam core 32 and conforms
to
second face 33. Studs 38 extend from face 33 a distance substantially equal to
the
desired thickness 39 of the concrete member 44. In a preferred embodiment,
concrete
member 44 has a thickness 39 of approximately two inches.
[0024) Studs 38, as illustrated in Figure 7, have a web 52, connecting caps 54
and
56. Cap 54 is embedded in the foam core 32, and cap 56 extends outwardly from
second face 33 of core 32. Cap 56 is subsequently embedded in concrete member
44.
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Since studs 38 have spacers 22 attached to an exterior face of cap 56 as
described
more fully below, provisions are required to permit fasteners (not shown) to
be
received and extend through cap 56. To prevent concrete from flowing into
contact
with the inner face of cap 56, a porous member 58 is affixed to the inner
surface of
cap 56. In the preferred embodiment, member 58 is EPS bonded thereto, although
those practiced in the art will readily recognize that other materials or
methods can be
used to provide the desired clearance for a fastener to be installed through
cap 56.
[0025] In addition to concrete member 44, party wall panel 30 also includes
two
support columns 46 laterally spaced one from the other, and further wherein
each of
the support columns 46 is intermediately positioned between two adjacent studs
38.
Support columns 46 are thicker than concrete member 44. In the preferred
embodiment, support columns 46 are also made from concrete and are formed
concurrently with and integral to concxete member 44 so that the columns 46
are
integrally connected to member 44. For added stiffening and reinforcement,
support
columns 46 may include one or more reinforcing bars 48 extending internally
there
along. Party wall panel 30 can also include concrete edge caps 42 at the
lateral ends
of panel 30. Edge caps 42 provide a sturdy mating surface for adjoining party
wall
panels 30 to one another and in the embodiment of Figure 3, cap 42 preferably
includes flat surfaces 42'. Flat surfaces 42' function as mating joints
between
adjacent panels 30.
[0026] Party wall panel 30 is formed by first placing the structural studs 36,
38 in
a mold or the like such that they maintain a desired substantially parallel
spaced
relationship as illustrated in Fig. 3 (i.e. so that in the final panel 30,
studs 36 are
arranged along a first desired face 34 and studs 38 are arranged in a like
manner along
a second desired face 33). Resinous foam is expanded in a manner to form a
foam
panel core 32. The foam expands around, and embeds within itself, studs 36, 38
thereby fixing the studs in their desired substantially parallel spaced
relationship.
Each stud 36 and 38 has a cap (such as cap 56 of stud 38 as shown in Fig. 7)
extending outwardly of either the first or second faces 34, 33 of the core 32.
Second
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face 33 of core 32 is formed to correspond to the desired contour of integral
concrete
member 44, support columns 46, and edge caps 42. After placing the core 32
(including studs 36 and 38 embedded therein) in a fabrication form (not
shown),
concrete is poured over the second face 33 of the core 32. The poured concrete
fills
and conforms to the contour of second face 33 to form edge caps 42 and columns
46.
The concrete is further poured so that concrete member 44 is formed to a
thickness 39
substantially equal to the extent stud 38 extends from the second face 33 of
core 32.
In this manner, the exterior face of caps 56 of studs 38 and the exterior face
40 of
concrete member 44 are substantially coplanar. Once integrally formed concrete
member 44, support columns 46 and edge caps 42 are cured, the panel can be
removed
from the fabrication form (not shown) and transported to the building site.
Party wall
30 could also be fabricated using the reverse of the procedure enumerated
above.
Specifically the concrete member 44 could be poured first and thereafter core
32 could
be formed against member 44 (using the appropriate form as described above).
The
timing of when core 32 is formed against member 44 is not critical regardless
of the
state of cure of member 44.
[0027] In the most preferred embodiment, party wall panel 30 is approximately
eight inches thick, eight feet wide, and twenty-nine feet high although panels
of other
dimensions are contemplated and included within the description herein. The
height
of twenty nine feet typically corresponds to the height from a basement
support
footing 13 (Figure 2) to the roof structure 15, 16 for dwelling units 12, 14
having a
basement and two stories above the basement. In those instances of
construction
where a party wall panel of smaller size (i.e. less than twenty nine feet) is
required, the
transported panel 30 can be cut in the field to a required size. Panels as
long as 52
feet high can be easily trucked from the fabrication plant to the construction
site using
conventional trucking equipment. The nominal eight foot width of panel 30
corresponds to current construction standards wherein studs are typically
laterally
spaced at sixteen or twenty-four inch intervals and fire-resistant sheets 24
attached
thereto typically have a height and width combination of four feet by eight
feet.
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[0028] Referring again to Figures 1-2, the supporting structure of each
individual
unit 12, 14 of the mufti-unit residence 10 is constructed with a space 18
between
adjacent units.l2 and 14. A crane (not shown) lowers individual party wall
panels 30
through space 18 so that panels 30 rest on basement support footing 13
(footing 13 is
preferably composed of crushed rock but can also be formed from concrete). The
base
of panels 30 are retained in position by basement concrete floors 17 which are
poured
after positioning of panels 30 in residence 10. The tops of panels 30 are
affixed to
roof structure 15, 16 and are thus maintained in a vertical relationship with
respect to
the remaining structure of units 12, 14. Adjacent party wall panels 30 have
abutting
edge caps 42. The abutting faces of edge caps 42 are sealed one to the other
with a
fire-resistant caulk (not shown). The supporting structure of units 12, 14 is
free
standing and not affixed to party wall system 20. This construction aids in
preventing
sound transmission paths between units, thereby further contributing to the
acoustic
impedance between adjacent units 12 and 14.
[0029] After the installation of party wall panels 30, spacers 22 (also known
as
spacer channels) are affixed to caps 56 of studs 38 with fasteners (not shown)
engaging both spacer 22 and cap 56. Spacers 22 are here shown as metal Z-
angles.
Spacers 22 typically have a height which may range between one-eighth inch to
two
inches to generally correspond to offset 45. Fire-resistant rated sheets 24
are then
affixed to spacers 22 on one side of party wall panel 30 and to the caps of
studs 36 on
the opposite side of panel 30 thereby defining sound channels 49. The
installation of
sheets 24 to spacers 22 and studs 36 would typically be done at the same time
that the
drywall installers are on site drywalling the units 12, 14. Sheets 24 are
affixed in a
spaced relationship from a respective face of party wall panel 30. Sound
channels 49
add further acoustic impedance to the party wall system 20 by creating an air
space
between sheets 24 and face 34. By increasing the air space (i.e. increasing
dimension
45) or by increasing the thickness of concrete member 44 (i.e. thickness 39)
the sound
impeding capability of wall 20 is enhanced to any required level. In the
preferred
embodiment as shown in Figure 3, a double layer of fire-resistant sheets 24
are affixed
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in an overlapping manner such that abutting seams of one layer are not aligned
with
those of the second layer. In a preferred embodiment, sheets 24 are gypsum
board.
The party wall panels 30, spacers 22 and fire-resistant sheets 24 thus
comprise a
completed party wall system 20 between adjacent residence units 12 and 14.
[0030] Referring to Figures 4-6, a second embodiment of a party wall system
120
is illustrated wherein like elements to party wall system 20 are identified
with like
reference numbers preceded by the numeral "1 ". Party wall system 120 includes
party
wall panel 130 which comprises foam core 132 having embedded therein studs 136
which extend through a first face 134 and studs 138 embedded therein which
extend
through a second face 133 of core 132. In this embodiment, studs 138 are also
C-
channel metal studs, however cap 156 is formed in conjunction with a second
cap wall
I 59. Cap 156 and cap wall 159 define a space 160 therebetween for receiving
fasteners (not show) extending through cap 156. Cap wall 159 prevents concrete
from
flowing into contact with the inner surface of cap 156 during fabrication of
concrete
member 144 of party wall panel 130.
[0031] Concrete member 144 and support columns 146 are integrally formed in
like manner to those described for party wall panel 30 above. Party wall panel
130,
however, does not incorporate concrete edge caps like caps 42 on panel 30.
Instead,
party wall panel 130 includes a tongue 150 along one edge of panel 130 and a
like
shaped groove 151 along an opposite edge. In this manner, adjacent panels 130
can
be easily aligned with the adjacent panel 130 utilizing the mating of tongue
150 of one
panel 130 into groove 151 of the adjacent panel 130. The panels 130 are sealed
at
their tongue and groove edges using a fire-resistant caulk as described above.
[0032] Party wall system 120 also includes the use of spacers 126 to affix
fire-
resistant sheets 124 in a spaced relationship to concrete member 144 thereby
defining
a sound channel 149 therebetween which functions as additional noise
insulation. The
height of spacers 126 preferably generally corresponds to the desired
thickness 145 to
which studs 136 extend from first face 134 of core 132 as discussed above. In
this
embodiment, spacers 126 are shaped as metal sound channels. Those practiced in
the
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art will readily recognize that different spacer geometries can be used to
meet the
intent of creating sound channel 149.
[0033) In the foregoing description those skilled in the art will readily
appreciate
that modifications may be made to the invention without departing from the
concepts
disclosed herein. For example the wall embodiment of Figure 3 is shown using
sound
channel spacers 22 having a "Z" shaped cross section while the embodiment of
Figure
4 shows a sound channel spacer having a "top hat" shaped cross section. One
skilled
in the art will recognize that these two sound channel spacers are
interchangeable in
this application and also that numerous other sound channel spacer geometries
could
also be implemented. Such modifications are to be considered as included in
the
following claims, unless these claims expressly state otherwise.
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