Patent application title: TRUE FLUSH-MOUNTED GAS FIREPLACE
Lothar Dan Binzer (Langley, CA)
IPC8 Class: AF24B1192FI
Class name: Stoves and furnaces fireplaces or accessories front barrier or guard
Publication date: 2011-02-24
Patent application number: 20110041832
Patent application title: TRUE FLUSH-MOUNTED GAS FIREPLACE
Lothar Dan Binzer
PERKINS COIE LLP
Origin: SEATTLE, WA US
IPC8 Class: AF24B1192FI
Publication date: 02/24/2011
Patent application number: 20110041832
A manufactured fireplace is adapted for flush-mounting within a pre-sized
opening in a wall structure without the need to double the layers of
drywall surrounding the opening. The fireplace metal facing panels are
manufactured to be flush from the fireplace window to an outer edge of
the panels. Non-combustible board is attached over the panels during
manufacture of the fireplace, obviating the need for installers to size,
cut and attach non-combustible board to the fireplace panels on site then
to attempt to achieve a flush-mounting by doubling up the layer of
drywall surrounding the fireplace opening. The fireplace including the
attached non-combustible board facing is shipped to a work site for
1. A pre-fabricated gas fireplace assembly for installation into a
structure, comprising:a firebox;a window for viewing the inside of said
firebox;a plurality of metal panels at least partly surrounding said
window;each of said panels being planar between an inner edge of each
panel that is proximal to said window and an outer edge of said panel
that is distal from said window, and including an outer portion for
fastening said panel to a stud in a wall framework;a layer of
non-combustible board overlying and being attached to the surface of each
of said panels to substantially cover said panel;wherein the firebox, the
panels and the non-combustible board define a pre-fabricated fireplace
assembly prior to introduction into the structure.
2. The pre-fabricated fireplace assembly of claim 1 wherein at least one of said panels is disposed above said window and at least another of said panels is disposed along a side of said window.
3. The pre-fabricated fireplace assembly of claim 2 wherein said layer of non-combustible board attached to each of said panels comprises a single piece of non-combustible board covering all of said panels and defining an opening corresponding to said window.
4. A method of using the pre-fabricated fireplace assembly of claim 1 comprising the steps of:procuring delivery of said assembly to a work site;removing said board from said metal panels;fastening at least two of said metal panels to studs of a wood frame wall;re-securing said board to said metal panels; and,installing a single layer of drywall to said studs surrounding said fireplace such that the surface of said board is coplanar with the surface of said drywall.
5. A method for installing a fireplace assembly into a structure, the method comprising the steps of:manufacturing a fireplace;attaching non-combustible board to the facing panels of the fireplace during manufacture of the fireplace;thereafter, shipping the fireplace assembly to an installation location; and,installing the fireplace assembly within a pre-sized opening of the structure at the installation location.
FIELD OF THE INVENTION
This invention relates to an improved flush-wall mounted gas fireplace.
BACKGROUND OF THE INVENTION
Gas fireplaces typically include a firebox, a viewing window and painted metal facing panels surrounding the viewing window. Referring to FIG. 1, a bottom panel 10 covers the gap between the floor of the firebox 12 and the floor of the structure in which the fireplace is seated. A top panel 16 is designed to protect the wall surface above the fireplace from excessive heat rising from the front of the fireplace and to shield the opening above the firebox. Side panels 20, 22 extend along the sides of the viewing window 24. Over the past several decades, one or more of the panels have included grills or louvers (not shown) to act as air intakes or exhausts, or for purely decorative purposes.
The fireplace is secured to the wood frame studs 26, 28 by means of fasteners 30 extending through a peripheral attachment flange 32 extending outward from the panels. Gas fireplaces are usually designed and dimensioned such that the metal panels substantially flush fit to the surrounding wall after drywall has been installed to abut against the fireplace panels. In order to achieve this, the panels stand out from the attachment flange 32 by an amount equal to the thickness of the drywall (about 1/2''-5/8''), as shown at 34 in FIG. 1A.
A so-called "contemporary" style of fireplace has a look characterized by a minimalist approach, with flat featureless panels and in which no louvers are visible. It is currently popular to take the contemporary look a step further such that as little as possible of the external fireplace structure is visible when it is installed. Preferably only the viewing window is visible when the fireplace is fully installed in a wall. Covering the metal panels of the fireplace in order to achieve that look presents challenges to builders and installers. Installers mask the panels by cutting pieces of non-combustible board (such as so-called "cement board") to the precise sizes to match the dimensions of the panels, then glue or otherwise secure the board to the surface of the panels.
Without more, as shown in FIG. 2 and FIG. 2A, this results in a standout 40 of the cement board 42 from the plane of the surrounding finished wall 44 as the cement board adds a layer of thickness to the fireplace facing. In the many cases where such a standout is aesthetically unacceptable, builders and installers will adopt one of two solutions. One approach is to build a slight recess into the wall frame corresponding to the footprint of the fireplace so as to anticipate the extra thickness of the cement board. This allows for a seamless joint between the cement board and the surrounding drywall such that only a viewing window is visible in the surface of the finished wall. However the framing detail needed to build a recess in the wall frame requires design effort and expense.
Instead, installers often choose to simply apply a second layer 46 of drywall on the wall surrounding the fireplace as illustrated in FIG. 3. If successful, this approach masks the panels and presents the appearance of a continuation of the wall to the edge of the viewing window, albeit at the additional cost in materials and space that double drywalling entails. There also remains a problem in reliably securing the cement board to the metal panels. As the fireplace cycles between heating and cooling, the metal expands and contracts, while the non-combustible board does not. As a result, the attachment of the board to the panels becomes compromised over time, as does the joint between the board and the drywall.
It is therefore an object of the present invention to provide a gas fireplace and a method of installing it such that substantially only the viewing window is visible in the finished wall but that provides for more reliable and simpler flush-mounting of the unit to the surrounding drywall or other wall finishing than the prior art fireplaces allow.
SUMMARY OF THE INVENTION
According to the invention, the standout that is normally provided between the surface of the metal facing panels and the attachment flange is eliminated, such that the surfaces of the panels are co-planar with an outer portion of the panels that is used to secure fasteners through the portion and into the wood frame studs. The fireplace is manufactured with a layer of non-combustible board pre-installed over the panels.
The thickness of the non-combustible board is approximately equal to the thickness of the drywall that is typically used to finish the surrounding wall, while the thickness of the metal panels is small. Alternatively, the combined thickness of the non-combustible board and the metal panels is approximately equal to the thickness of drywall.
According to the preferred embodiment of the invention, the non-combustible board is provided as a unitary piece surrounding the viewing window. The board may be affixed to the frame surrounding the viewing window in any suitable manner, but the preferred embodiment contemplates using machine screws and nutserts that allow for limited movement of the screw in the nutsert to accommodate expansion and contraction of the panels in relation to the non-combustible board. The edges of the board are beveled as in typical drywall edge beveling to facilitate flush finishing of the fireplace to the surrounding wall.
The fireplace so constructed is delivered to a worksite with the board facing installed. At the site, the installer removes the board facing to access the metal panels, installs the fireplace, then replaces the board before finishing the joint to the surrounding drywall.
The invention simply and effectively overcomes the problems that have plagued designers and installers in seeking to provide a flush-mounted gas fireplace wherein only the viewing window is visible in the finished wall.
In one aspect the invention comprises a pre-fabricated gas fireplace assembly for installation into a structure. The assembly includes a window for viewing the inside of the firebox and metal panel facings around the window. The metal panels are planar from the edge of the window to the outer edge of the panel and include an outer portion for fastening the panel to a stud in a wall framework. A layer of non-combustible board overlies and is attached to the surface of each of the panels and is provided with the fireplace assembly prior to introduction into the structure.
In another aspect, the invention comprises a method of using the pre-fabricated fireplace assembly described above, comprising the steps of procuring delivery of the assembly to a work site, removing the board from the surface of the panels, fastening at least two of the panels to studs of a wood frame wall, subsequently re-securing the board to the panels, and installing a single layer of drywall to the studs surrounding the fireplace such that the surface of the board is coplanar with the surface of the drywall.
In yet another aspect, the invention is a method for installing a fireplace assembly into a structure. A fireplace is manufactured in the course of which non-combustible board is attached to the facing panels of the fireplace. Thereafter, the resulting fireplace assembly is shipped to an installation location. The fireplace assembly is installed within a pre-sized opening of the structure at the installation location.
The foregoing was intended as a broad summary only and of only some of the aspects of the invention. It was not intended to define the limits or requirements of the invention. Other aspects of the invention will be appreciated by reference to the detailed description of the preferred embodiment and to the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be further described by reference to a detailed description of the preferred embodiment and to the drawings in which:
FIG. 1 is a front perspective view of a typical prior art gas fireplace installed but not yet secured in the wood frame of a wall;
FIG. 1A is an enlarged view of a portion of FIG. 1 showing the attachment flange and facing panel standout of a prior art gas fireplace for securing to a wood frame;
FIG. 2 is a front perspective view of a prior art gas fireplace installed in a drywalled wall, and wherein an installer has secured pieces of cement board to hide the metal facing panels;
FIG. 2A is an enlarged view of a portion of FIG. 2 showing the standout of the cement board in relation to the surrounding drywall;
FIG. 3 is a perspective view of a prior art gas fireplace installed in a double drywalled wall according to a prior art installation approach;
FIG. 4 is a side cross-sectional view of the fireplace according to the preferred embodiment of the invention as manufactured to include non-combustible board secured to the metal panels surrounding the firebox;
FIG. 4A is an enlarged view of a portion of FIG. 4 showing the beveling of the edge of the non-combustible board in accordance with the edge-beveling practice of typical drywall;
FIG. 5 is a side cross-sectional view of the fireplace, but with the non-combustible board facing removed;
FIG. 6 is a front perspective view of the fireplace, with non-combustible board facing removed; and,
FIG. 7 is a front perspective view of a fireplace with the non-combustible board facing removed, installed in the wood frame of a wall;
FIG. 8 is the view of FIG. 7 but with the non-combustible board facing re-secured to the panels of the fireplace;
FIG. 9 is the view of FIG. 8 but with the surrounding wall finished with a single layer of drywall;
FIG. 10 is an exploded view of the fireplace, including non-combustible board facing, showing a nutsert and machine screw to secure non-combustible board facing to the metal panels of the fireplace;
FIG. 10A is a detail view of a portion of FIG. 10; and,
FIG. 10B is a detail view of a portion of FIG. 10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 4 illustrates a fireplace 50 according to the invention. The firebox 52 is framed by top (54), bottom (56) and side (58) panels and a viewing window 59 extends between them. The fireplace is designed to be installed by securing it to the studs of a wood frame wall structure that define a pre-sized opening for the fireplace. Outer edge portions 65, 67 of the panels 54 and 58 (best seen in FIG. 7A) will overlay the studs so as to enable fasteners to be driven through the portions 65, 67 and into the underlying stud.
The lateral profile of the fireplace is designed to allow flush mounting of the fireplace into a wall finished with a single layer of drywall, with substantially only the viewing window being visible. This is largely achieved by making outer edge fastening portions 65, 67 co-planar with the balance of the panels, such that there is no step or standout between the fastening portions 65, 67 and the balance of the panels. The metal panels are made flush from the window they define to their outer edges.
Non-combustible board, such as cement board 60, is secured to the front of the panels during manufacture, as best seen in FIG. 4A. The combined thickness of the non-combustible board 60 and the metal panels is preferably approximately equal to the thickness of the drywall typically used to finish the surrounding wall, namely 1/2'' to 5/8''.
In order to facilitate finishing the joint between the fireplace and the surrounding drywall, the outer edges of the cement board 60 are beveled as at 72 (see FIG. 4A) to accommodate mud applied by finishers to the joint between the cement board 60 and the surrounding drywall 74. The non-combustible board may be provided as a unitary piece covering all of the panels 54-58.
Nutserts 76 (see FIG. 10) are provided in the front surface of the panels 54-58 and the cement board 60 is secured to the panels by means of machine screws 78 threaded into the nutserts 76. The machine screws 78 and the nutserts 76 provide a small amount of play allowing the panels to expand and contract slightly when heated and cooled without substantially degrading the retention of the cement board on the panels.
FIGS. 7-9 illustrate the installation of a fireplace according to the preferred embodiment and the finishing of the surrounding wall to result in a flush-mounted gas fireplace with only the viewing window being visible in the finished wall. The fireplace is manufactured with the cement board secured to the metal panels as illustrated in FIG. 4 and is shipped to a work site. At the work site, the installer first removes the cement board from the panels of the fireplace by removing the machine screws 78. This exposes the underlying metal panels 54-58 and panel outer attachment portions 62-68.
Referring to FIG. 7, the fireplace is secured to the wood studs 80, 82, 84 by means of nails fastened through the fastening portions 65, 67 (labeled in FIG. 7A). The cement board 60 is then re-fastened to the panels 54-58 by reinserting and rethreading the machine screws 78 into the nutserts 76 that are secured to the metal panels 54-58, as shown in FIGS. 8, 10 and 10A.
Referring now to FIG. 9, the installer then installs a single layer of drywall 86 to the surrounding wall structure so as to abut the edges of the cement board 60. As both the drywall and the fastening portions 65, 67 are mounted against the surface of studs, and because the combined thickness of the cement board and the fastening portions is approximately equal to the thickness of the drywall, the surface of the cement board 60 in the installed fireplace is co-planar with the surface of the surrounding drywall 86.
Where the surface of the viewing window has been made co-planar with the surface of the cement board, its surface will also be co-planar with the surface of the drywall, thereby achieving an overall flush look to the fireplace. Mudding of the beveled joints between the cement board and the drywall completes the finishing of the wall save for painting.
While the figures show the viewing window 59 as recessed in relation to the panels 54, 56, 58, the viewing window may optionally also be made to stand out from the panels by an amount equal to the thickness of the non-combustible board 60. This would result in the viewing window being flush with the cement board and with the surrounding finished wall into which the fireplace is installed.
It will be appreciated that the fireplace according to the invention allows easy flush-mounting of the fireplace into a finished wall, without the need for an installer to measure the fireplace panels and cut pieces of cement board on site to fit over the panels, and further avoid the need to double drywall the surrounding wall to achieve a flush finished installation. This represents a significant economy of effort and cost in installing gas fireplaces with the desired minimalist look.
It will be appreciated by those skilled in the art that the preferred and alternative embodiments have been described in some detail but that certain modifications may be practiced without departing from the principles of the invention.
Patent applications by Lothar Dan Binzer, Langley CA
Patent applications in class Front barrier or guard
Patent applications in all subclasses Front barrier or guard