Ceiling devices and methods of installing same

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Patent issued

01/12/1993

Inventor(s):	Reynolds, Henry B.
Application	No. 07/786,600 filed on 11/01/1991
Current US Class	52/484, 52/486
Field of search	52/741, 52/484, 52/486, 52/488
International Classes:	E04B 100
Examiners
Primary	Chilcot, Jr. Richard E.
Secondary	Aubrey Beth A.
Attorney, agent or firm:	Rhines; William G.
US patent references	3767008, 3775929, 3977144, 4275541, 4991370
Foreign patents	576180 (04/30/1959, CA)

This invention relates to devices and methods for installing ceilings madefrom tiles that are supported by a suspension grid that is not visiblefrom the underside of the ceiling. One embodiment comprises channels thatform the suspension grid, channel wall supports for supporting the gridwhere the ceiling abuts the walls, and hangers that are capable ofestablishing the ceiling level as well as supporting the suspension gridin its mid-span regions. Another embodiment comprises a method ofinstalling the wall hangers, suspension grid channels, and hangers.
BACKGROUND OF INVENTION
In the field of building construction, it is a common practice to installhung ceilings in new or existing structures. Various alternativestructural systems and methods are used for hanging a support frame at theapproximate level of the desired ceiling and then affixing tiles, panelsor the like to the support frame. Such frames typically are formed fromchannels which, in cross section, are in the shape of a "T", an "I", orother known per se shape. They may be made from aluminum, steel, plasticor other materials that are suitable for the intended use. The tiles,panels and other surfacing materials commonly are made from cellulose,plastic, glass, and other appropriate materials.
Many such ceiling systems are known and in common use. However, many haveshortcomings and difficulties that make them difficult to install,unattractive, or otherwise unacceptable in varying degrees. For example,an objection to many such systems is that they are not adapted to concealthe support frame members. In some, a resulting display of the geometricconfiguration of the support frame unacceptably compromises the aestheticsof the other ceiling constituents and of the ceiling as a whole. It isoften difficult, or at least requires special steps, to level the supportframe throughout its span to the extent necessary to produce a ceilingthat is flat and planar, and is otherwise satisfactory functionally and inappearance. The source of this particular difficulty lies in the virtualimpossibility of constructing the relatively heavy and large dimensionedframe of a building so that the bottom surfaces of the joist form a flatplane. The importance of this is that it is the under surfaces of thesejoist (which are referred to herein as "ceiling joist", although,typically they also serve as the floor joist for the floor next above)which form the base to which the ceiling is anchored. This problem hasbeen addressed in a variety of ways. One is to attach narrow strips ofwood, called "furring strips", to the underside of the ceiling joist atsubstantially right angles to the long direction of the joist. The effectof this is to average out undulations and other discontinuity in and asbetween the bottom surfaces of the floor joist collectively. However,frequently even this isn't sufficient, and shims and/or other adjustmentsmeans are resorted to in order to bring the support grid into anacceptable degree of parallelism. In the alternative, hanger wires, orthreaded mounts, or pulley-like devices, or multi-holed straps or othersuch means are sometimes resorted to, particularly where a hung ceilingtile grid is being installed, in order to achieve the desired results.
In connection with the foregoing, reference is made to the following U.S.Pat. Nos. 4,696,141, 4,760,671, 4,089,146, 4,169,340, 3,841,048,3,942,561, 3,863,413, 3,988,871, 3,983,116, 3,995,823, 3,998,020,3,798,419, 3,640,042, 3,708,941, 3,714,753, 3,742,674, 2,994,112,2,996,765, 3,004,644, 3,093,548, 3,070,851, 3,344,465, 2,406,771,1,578,964, 2,101,952, 2,389,171, 2,725,127, and 2,963,751.
Accordingly, it is an object of this invention to provide means forinstalling ceiling materials.
It is a further object to provide means for achieving the foregoing purposeby which a support structure may be perfected that is concealed.
A further object is to provide means for achieving the foregoing objectivesin which the need is eliminated for adjustable supports, shims, furringstrips, moveable hangers, and other distance modifiers for causing thesupport frame to be positioned in a flat planar orientation.
Still another object of this invention is to provide means for achievingthe foregoing objectives wherein the support means includes means forestablishing the planar position of the ceiling system.
SUMMARY OF THE INVENTION
Embodiments of this invention comprise a ceiling made from tiles that aresupported by a suspension grid wherein the grid is concealed within theedges of the tiles where they abut the walls and each other. The grid issupported on the walls by means of concealed wall brackets into which theoutermost grid channels may be affixed or simply by outer channels affixedto the wall by means of screws, nails or other fastening means throughholes in the channels. In mid-span, it is supported by hangers that areadapted to extend downward a predetermined distance from the associatedsupport structure of the building in which the ceiling is located and tohave the mid-span sections of the support grid channels affixed thereto.As such, the channels describe a flat plane.
Other embodiments include methods for installing a ceiling wherein eitherwall channel brackets are placed in position and wall channels are thenaffixed to the brackets or channels having holes in their back wall areaffixed directly to the supporting wall by means of screws, nails or otherfastening means. Hangers are positioned on the building support frameafter the hangers have been formed as may be necessary to provide supportfor the grid from the support frame while positioning it in desired flatplanar configuration. The ceiling tiles are then positioned in supportedrelationship with the grid and wall channels, with the channels concealedwithin the edges of the tiles.

I claim:
1. A method of erecting a support system for a hung ceiling which includesceiling tiles having edge slots and also includes
a plurality of channel members, each of which has an elongated U-shapedreceptacle that is dimensioned and configured to receive and retain theedge of ceiling tiles to be associated therewith,
means for retentively affixing selected among said channel members towalls, each with its respective U-shaped receptacle substantiallyhorizontal and facing outwards from the wall to which it is affixed,
and a plurality of hanger means, each of which consists of an elongatedhanger that has mounting means at one of its ends adapted to retain one ofthe remaining of said channels, and is adapted for fixation at the otherof its ends to an overhead support with the U-shaped receptacle of thechannel being retained by it facing toward that of one of said selectedchannels,
comprising the steps of
selecting a starting wall of the room in which said system is to beinstalled,
selecting a finishing wall opposite said starting wall,
marking with wall hanger position marks the desired level of the ceiling tobe installed at sequential locations on the wall surfaces of said room,
connecting sequential among said wall hanger position marks by means ofstraight lines around said room,
affixing some of said channels to said walls at predetermined positionswith respect to said lines, with their U shapes facing away from the wallon which each respectively is positioned, level strings from sequentiallocations along the channels on one side of said room to channels on theopposite side of said room,
positioning said hangers at successive locations along each of said stringsthat are at the same distance from each location on either side as thedimension in that direction of the tiles to be installed in said ceiling,with the channel mounting means on each oriented downward and with thetopmost end of said hanger juxtaposed to the surface to which said hangeris to be attached and with said channel mounting means so positioned thatwhen such channels are mounted thereby on said hangers and ceiling tilesare retentively positioned thereon by means of their edge slots, theundersurfaces of said tiles are substantially coplanar with theundersurfaces of ceiling tiles positioned in said channels affixed to saidwalls, affixing each of said hangers to the surface to which it is to beattached,
and positioning channels in said hangers with each such channel oriented inthe direction of the same one from among all of the channels affixed tothe walls of said room.
2. The method described in claim 1 including the additional steps of
installing a first row of ceiling tiles along the length of and outwardfrom channels affixed to one of said walls, with the channels retentivelypositioned in the channel hanger means forming the row next to said wallmounted channels having one leg of the U of each positioned in the edgeslot of the tiles forming said first row of tiles,
installing additional rows of ceiling tiles seriatim in sequential rowsproceeding away from said first row of tiles, with the tongues of eachresiding in the edge grooves of the corresponding tiles in the row nextpreviously completed, and with the lower leg of the U of each row ofhangers positioned in the edge slots of installed tiles correspondinglypositioned until the last such row necessary to complete said ceiling, and
installing the last row of ceiling tiles with their tongues residing in theedge slots of the rows of tiles immediately next installed and with theiropposite edges positioned in the channels retentively positioned on thewall opposite that at which the process was begun.

DESCRIPTION OF DRAWINGS
This invention may be understood from the description which follows andfrom the accompanying drawings in which
FIG. 1 is a perspective view of a hanger structure useful in practicing thepresent invention,
FIGS. 2A and 2B are plan views of other embodiments of structures as shownin FIG. 1,
FIG. 3 is a perspective view of a channel structure useful in practicingthe present invention,
FIG. 4 is a perspective view of a wall hanger structure useful inpracticing the present invention,
FIG. 5 is a perspective view of a wall hanger being positioned inconnection with an embodiment of the present invention,
FIG. 6 is a perspective view of an embodiment of this invention,
FIG. 6A is a cross-sectional view of an alternative means of affixing edgechannels to their associated walls,
FIG. 7 is an elevation cross-sectional view of an embodiment of thisinvention, and
FIG. 8 is another elevation cross-sectional view of the embodiment of thisinvention shown in FIG. 7.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring first to FIG. 1, there is depicted a leveling hanger 10 useful inpracticing the present invention. As such, it is made from aluminum,steel, plastic or other suitable material, preferably by having beenstamped from base stock in strip form. It includes a series of fastenerholes 12, 12', 12" . . . 12n, through which nails, screws, or other knownper se fasteners may be inserted in order to provide means for attachingthe hanger as hereinafter described. It also includes a channel mountaperture 14 and an optional ceiling level slot 16. The purposes of thesewill be apparent from the description which follows. The optional slot 16as shown is positioned 11/8 inches from the nearest end of the hanger 10.This distance is in anticipation of using wall hangers as shown in FIG. 6in connection with a ceiling support grid that is to support ceiling tilesthat are 1/2 inch thick, whose final position is to be such that theirlower or finish surfaces are to be 13/8 inches below the under surface ofthe already existing ceiling, or underside of the ceiling joist, (as thecase may be) to which the ceiling is to be juxtaposed. Although thehangers 10 are desirably formed of a more or less uniform length, such asabout 9 inches overall, it will be seen from FIGS. 2A and 2B that themultiplicity of fastener holes in each such hanger, in addition to theirother functions, may be used to extend the effective length of a hangerassembly to give it a length greater than that of a single such hangeralone. Thus, as is depicted in each of these illustrations, a hangermember 10 is fastened to a second hanger member 10A by fastening means,such as sheet metal screws or nuts and bolts 18, 18A that are positionedin the fastener holes in both. As will be seen from comparing FIG. 2A withFIG. 2B, the total length of the resulting structure may thereby be easilyregulated by simply adjusting the amount of overlap of the two hangersmembers in each case.
FIG. 3 illustrates a channel 20 that may be used with embodiments of thisinvention. It may be formed from material, such as metal or plastic, whichis the same as, or is compatible with the materials from which the hangers10 and the wall hangers 30 are made. It will be noted that the channels20, which typically may be about 8 feet in length, include a portion whichis U-shaped in cross section, with a lip 22 extending along the length ofthe edge of one of the legs of the "U", and that the lip includes stringline notches 24. The latter are advantageously placed at 1 foot intervalsalong the length of the lip 22, beginning 6 inches from the end of a givenchannel. By this means, a notch that would otherwise be positioned at eachend of the channel, will be spaced from the end by one half the distancebetween those that are in mid-span. The purposes for having the lip andthe notches, and for the spacing of the latter, will be apparent from thedescriptions which follow. It should also be noted that the channels 20may optionally or alternatively include holes 26 spaced along the backwall of the channel. By this means, wall hangers such as those shown inFIG. 4 need not be used, since the outside perimeter channels in a givensystem may thereby be fastened directly to the walls which support them bymeans of nails, screws, or other fastening means. Further, by that means,optional ceiling level slots of the type shown as 16 in FIG. 1 need not beused or present since, as will be apparent from the descriptions whichfollow, the plane of the underside of the hung ceiling to be newlyinstalled may be established by alternative means.
FIG. 4 illustrates a wall hanger structure that may be used in embodimentsof this invention. It shows a wall molding hanger 30, which may be formedfrom materials which are the same as, or compatible with, those of thehangers 10 and/or the channels 20. As shown, they also include a portionwhich is substantially U-shaped in cross section with an edge lip 32 inwhich is positioned a mounting hole 34. Again, the purposes of thesestructural features will be apparent from the descriptions which follow.
It is to be understood that the various tasks of fastening as described maybe carried out using standard, known per se fastening means that areappropriate for each intended use. Thus, fastening to an existingplasterboard ceiling and/or walls may be by means of so-called "togglebolts", which are installed by drilling a hole in the surface to whichattachment is to be made. The bolt is inserted into the hole, and themounting screw is then turned. This causes the threaded portion to bedrawn toward the screw head and the bolt cartridge to collapse, lockingthe assembly to the plasterboard. Thereafter, the bolt may be removed andthe bolt remounted to secure objects to the structure beneath by engagingthe bolt into the threads of the assembly. Wood screws may also be used.If they are, it is advantageous to align them with underlying studs orjoists where softer materials intervene, such as plasterboard walls orceilings. In some installations, however, such as over existing woodpaneling, such screws may be used directly without special regard to thecorresponding position of the studs or joists. Nails, includingplasterboard nails, screw nails, or other such appropriate devices, mayalso be used. If masonry is the underlying material, it may be drilled andhave plastic or lead anchors inserted into the drill holes to receivescrews, nails or other appropriate fastening devices.
To illustrate embodiments of this invention, an example will be used inwhich the ceiling finishing material is in the form of square ceilingtiles. Obviously, however, the general approach that will be described isreadily adaptable to situations where the ceiling material is in someother basic shape, such as rectangles. Further, the installation site maybe different from or less regular than the square or rectangular room thatwill be described in the following example. It will also usually desiredto have the tiles evenly spaced; i.e., with any rows less wide than a fulltile width reduced to the same width in opposite outer rows, so that theoutermost (or "border") tiles that are adjacent to opposite walls are ofthe same width. Of course, some other configuration of tiles may also beused where so desired.
Installation of a ceiling embodying the present invention may include thefollowing steps: (1) "squaring" the room in preparation for installing theceiling, (2) fastening wall molding hangers in place, (3) fasteningchannels to the wall molding hangers, (4) preparing for and installinghangers, (5) installing channels on the hangers, and (6) finishing theceiling.
(1) Squaring the room
It is generally preferred, for reasons of symmetry and other aestheticconsiderations, that all rows of tiles comprising a ceiling should be ofthe same width. If that isn't possible geometrically, at least the borderrows on opposite walls may be made to have the same width. It is alsousually preferred for every border row to be 6 inches or more in width tohave the best appearance. To plan the desired configuration for the tiles,and therefore the positioning of the associated hardware, the walls arefirst designated as (1) the "starting wall", i.e., the wall adjacent tothe first border row of tiles to be installed, (2) the "finishing wall",i.e., the wall adjacent to the last border row of tiles to be installed,(3) the left sidewall, i.e., the wall that is to the left when facing thestarting wall, and (4) the right sidewall, i.e., the wall that is to theright when facing the starting wall. The usual and preferred orientationof the ceiling joist vis-a-vis the walls so designated, particularly wheresuch joists (rather than an existing ceiling, for example) are to beutilized as the primary support for the hangers 10, is for the left andright sidewalls to be so selected that the ceiling joist are substantiallyparallel to them. In carrying out an embodiment of this invention, firstthe distance from the starting wall to the finishing wall is measured. Ifthe distance so measured is such that a whole number of tiles will not fitacross that dimension, either (a) add the width of a single tile to theoverage if the overage less than one-half the width of a single tile, or(b) subtract the width of a single tile if the overage is greater than thewidth of a single tile. In either case, (c) divide the difference betweenthe wall to wall distance and the cumulative width of the whole number oftiles to be utilized resulting from (a) or (b) above, (as the case maybe), by 2. The result of that calculation will determine the distance fromeach of the starting and finishing walls of the abutment between theborder row of (partial width) tiles and the row of (full width) tiles nextadjacent to it. It will also establish the layout of the tile rows whichborder the sidewalls if the distance between the sidewalls is the same asthat between the starting and the finishing walls: otherwise the sameprocedure may be followed to establish the width of the border rowsadjacent to the sidewalls.
(2) Fastening wall molding hangers in place
First, the desired level for the ceiling to be installed is determined andmarked on the walls at each corner of the room. The existing ceiling levelmay not be level for a variety of reasons: e.g., the floor has settledwith respect to the existing ceiling or ceiling joist, or has otherwisearrived at an uneven distance from it. If it is desired to correct forthat condition in the new, hung ceiling, rather than using equal distancesfrom the ceiling-walls-corner intercepts, those measurements may beadjusted from one to the next so as to cause the finished ceiling to be inthe desired orientation and level vis-a-vis the other structural elementsof the room, and the points so determined marked on the walls. With thehanger held vertical, the ceiling level slot 16 on a hanger 10 ispositioned at the marks on the wall at each corner. A second, mark is madeat each such corner at the end of the hanger nearest the slot 16. In ahanger as described above, that second mark in each case will be 11/8inches above the first mark. A chalk line is then snapped on each wallbetween each pair of secondary marks, so that each end of each such chalkline joins the end of a successive chalk line mark. The result is acontinuum of chalk line marks around the entire room that is at a fixeddistance (in this example, 11/8 inches) above the level desired for thenew ceiling. A location along each such chalk line is identified that isnear, and preferably not more than 2 feet from, a corner, and is over awall stud, if such studs are to serve as the primary support into whichaffixing fasteners are to be driven. Pilot holes, typically 1/8 inch indiameter, are drilled at reasonable intervals along each chalk line, suchas about 4 feet. At each of these locations, as is shown in FIG. 5, a wallmolding hanger 30 is loosely affixed to the wall by means of a screw 36 orother suitable fastening device. After the edge channels have beeninstalled, as hereinafter described, the fasteners which hold the hangers30 in place may be tightened down, thereby fitting the edge channelssnugly against their associated wall surfaces. Alternatively, usingchannel with holes 26 arrayed along its back wall as shown in FIG. 3, sucha channel may be affixed dirextly to the wall by using screws or otherknown per se fastening devices. This arrangement is shown in greaterdetail in FIG. 6A.
(3) Fastening channels to the wall molding hangers
As will presently be seen, the string line notches 24 in the channels 20,after the channels are fastened to the wall hangers 30, are to serve asreferences from which level strings are to be run. Before such channelsare fastened, the string line notches 24 of each should be aligned withthe corresponding notches in the channel in the opposite wall of the room.The border tiles at each corner should be of such dimensions as to causeeach of its inner edges (i.e., those not residing in the channels in whichsuch tiles are retained) to align with the abutment lines between theborder rows and the rows of full dimension tiles next adjacent to them. Toachieve that, a length of channel is cut off at such a point that a stringline notch 22 is the same distance from the end of the channel as thewidth of the border row of tiles that is to reside at right angles to thechannel at that location, plus the distance by which any tongue in theedge of each tile extends beyond the edge of the finished surface of thetile. Thus, if the border tile width at that point, calculated ashereinbefore described, is 91/2 inches, the first string line holes in thechannels should be 91/2 inches from the channel ends. But if fulldimension tiles are to be used for the border tiles at that point, thestring line notches should be 12 inches from the channel ends. Similaradjustments are made around the room, with full length channels 20 betweenthe end channel pieces, so that each inner string line notch 22 is on a 12inch center from each inner string line notch next adjacent to it. Thechannels 20 so prepared are then inserted into the hangers 30 with the lip22 of each channel 20 facing upward, and are so positioned as to abut theinside of one or more hangers 30. This is illustrated on the right side ofFIGS. 6 and 7, after the support fasteners 34 have been tightened down soas to hold each hanger 30 snug against its associated wall. At outsidecorners, the channel ends may be mitered in order to impart a finishedappearance to them. At inside corners, they need not be mitered but,instead, the end of one may simply abut the side of the other. If the roomis irregular in plan view, its various jogs and intrusions may beaccommodated by forming inside or outside corners which also may becorrespondingly mitered or abutted. When this phase of the operation iscompleted, a continuum of channels will extend all around the room, withtheir U-shaped portions occupying the same plane.
(4) Preparing for and installing channels
A string, preferably made from nylon so that it will withstand hightension, is knotted at one end, and placed through the string line notchon the left side wall that is nearest to the starting wall, with the knotand string end residing inside the channel. The string is then stretchedacross the room. It will therefore be across the line of ceiling joist inthe situation as described. It is then fed through the corresponding firststring line notch in the channel on the right side wall, run inside thechannel, and then brought back out into the room through the second stringline notch in the same channel. Following that, a hammer or other heavyobject may be tied to the end of the string. The effect of this is to keepthe string taut and substantially flat across the width of the room fromone side wall to the other. If the side walls are so widely separated thatthe string sags, the sag may be eliminated by setting a mid-span hanger toact as a temporary support to level the string. The taut string sopositioned provides a reference for establishing a flat plane for thefinished ceiling by accurately positioning each hanger as hereinafterdescribed. One by one, hangers 10 are oriented vertically so that thechannel mount aperture 14 in each is oriented upward. With the hanger atright angles to the axis of the string and spaced from one of the sidewalls at a desired location along the string, the end 17 of the hanger 10next adjacent to the channel mount aperture 14 is held so that it justtouches the surface to which the hanger is to be attached, such as theunderside of a cross-oriented ceiling joist, or an existing ceiling, orthe side surface of a floor joist. No hanger should be overly distant(typically, not more than 4 feet) from each next adjacent hanger locationalong the length of the string, to ensure better level throughout. Thelocation of the string along the length of the hanger is then marked, asby the positioning of a thumb. In instances where the hanger is to besuspended from the bottom of a joist, using pliers or other appropriatemeans, the hanger is bent as shown in FIG. 6 to form a right angle in thedirection of the string at the position of the place so marked. Of course,this bending operation is not necessary in instances where the hanger,when finally positioned, is to be affixed to the side of a joist. Forreasons which will be apparent presently, the orientation of the openingto the channel mount aperture 14 during this operation and when the hangeris finally positioned should be facing away from the starting wall. Thehanger may then be inverted, so that its channel mount aperture 14 is atits lowermost end. As shown in FIG. 6 for the case of a bent hanger, itsright-angled portion will then be adjacent to and may be affixed to theexisting ceiling, the underside of the ceiling joist, or other intendedsupport surface 54. Of course, where it is intended to support the hangerfrom the side of a joist, the unbent hanger may simply be so oriented andaffixed. In either case, the fixation may be by means of nails, screws orother appropriate fastening means 52. The bottom end of each hanger soaffixed will then be exactly at the level of the reference string 50, asis also shown in FIG. 6. That level is slightly above, but is uniformlydistant from, the upper side of the ceiling tiles. This operation may thenbe repeated along the length of the string to complete one row of hangersupports. Thereafter, the string may be moved to placement withinsuccessive pairs of string notches and the foregoing steps repeated untilthe entire desired array of hanger supports has been established and fixedin place.
(5) Installing channels on the hangers
With the array of leveling hangers 10 so established, the border row 68 oftiles may be installed with its cut edge (or its tongue edge, if it is afull width, uncut ceiling tile) inserted into the channel 20 that wasaffixed to the starting wall, whether as shown in FIG. 6A, or in FIGS. 6and 7. Channels 20 may then be positioned in the channel mount apertures14 of those among the array of hangers 10 that form the first row parallelto the starting wall, with the lower legs of their respective U-shapedportions residing in the grooves in the sides of the border tiles 69. Thelip 22 of each channel 20, which is wider than the height if the entryhole in the side of channel mount aperture, is oriented upward to lockeach channel in place so that it cannot slide back out of its associatedaperture 14. The positioning and dimensioning of the apertures 14 and thechannels 20 vis-a-vis the lower end of the hangers 10 is to be noted. Whenthe inside of the leg of the U of channel 20 that is adjacent the lip 22is seated on the bottom of aperture 14 with the inside of the opposite legof the U inserted into the edge groove of the ceiling tile 60, the bottomor finish surfaces of the tiles will be coplanar with respect to eachother and to the bottom of the side wall channels. From the foregoing, itwill be apparent why, although a wide variety of shapes for the aperture14 is possible, it is preferred for it to be a "quadrate" which, as usedthroughout this Specification and the accompanying claims, means a square,or anything resembling a square in the broadest sense, including (withoutlimitation) a rectangle or other configuration having straight sides and afloor. As will be apparent from FIGS. 6 and 8, with this channel sopositioned, a second row of tiles 70 may be positioned with its edgetongue in the same groove of the tile 60 as is the leg of the channel 20.So positioned, the lower legs of the first row of channels 20 hanging fromthe hangers 10 are effectively concealed inside the interlocking tongueand groove surfaces of adjacent tiles. The effect of this is to providehanger supports for the tile sequences that are "blind", or not visiblefrom the underside of the finished tile ceiling. Following this, as shownin FIG. 8, another set of channels 10 may be positioned on the second rowof hangers, and then a third, and so forth.
(6) Finishing the ceiling
The foregoing process is carried out row after row towards completion ofthe entire ceiling. Installation of the last border row, which is to beplaced next to the finishing wall, is facilitated by removing anadditional portion (for example, about 3/8 inch) from the edge of thetiles that will reside next to the finishing wall. Any gap between thefinishing wall and the last row of outer tiles is obscured by the lowerflange of the channels that are affixed to the finishing wall. The result,at the end of the entire process, is to have produced a ceiling tilehanger system with tiles installed, in which the visible ceiling surfaceis substantially in the configuration of a flat plane. In that connection,the physical dimensions should be noted in a typical system, since it willillustrate relationships that are generally comparable and will producesimilar results in comparable cases. Thus, in the embodiment described,the ceiling tiles employed may be 5/8" thick, and have edge grooves thatare are 1/4" in width, thus leaving a 1/8" surface segment on the top sideof each edge groove and a 1/4" segment on the bottom edge. The width ofthe U shaped channels may then be set at 5/8". If the distance from thefloor of the hanger aperture to the bottom of the hanger is 1/4", thebottom leg of the side-facing U of the channel will extend 3/8" below thebottom of the hanger and the visible surface of a suspended tile will be1" below that floor. Since the wall hanger hole is 1/8" above theoutermost edge of the lip of a channel positioned in the wall hanger, andsince that lip is 3/8" wide, the bottom leg of the channel will be 5/8"below the bottom of the wall clip and level with the bottom of channelsheld in the mid-span hangers.
From the foregoing it will be apparent that this invention makes itpossible to install a hung ceiling quickly, easily and effectively, thatwill be level and substantially free at its visible surfaces from anyevidence of its associated suspension structures. Further, uniqueinstallation methods are disclosed herein which embody this invention aswell. Thus it is possible, through practice of this invention, to producenew and novel structures that overcome a variety of difficulties that havebeen experienced with prior art devices. Accordingly, it is to beunderstood that the embodiments described are by way of illustration andnot of limitation, and that a wide variety of embodiments may be madewithout departing from the spirit or scope of this invention.