US 3919820 A
A wall structure is described which contains joints sealed by a system operating in accordance with the rain screen principle. Adjacent panels have facing edge grooves and an air sealing member between the panels on the interior side thereof. A rain screen baffle, retained in only one of said grooves, spans the gap between the grooves with a flexible screen and cooperates with the air sealing member to create interiorly of the screen a pressure equalization chamber. Preferably there are also means to urge the screen into contact with outer sides of the two grooves.
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Description (OCR text may contain errors)
United States Patent [191 Green 5] Nov. 18, 1975 WALL STRUCTURE AND DEVICE FOR 3,813,838 6/1974 Brown et al. 52/396 SEALING THEREOF  Inventor: Robert Franklin Green, Morrison, f' Stltherland C010 Asszstant Exammer-Carl D. Friedman Attorney, Agent, or Firm-Robert M. Krone; James W.  Assigneez Johns-Manville Corporation, McClain Denver, C010.
 Filed: Dec. 13, 1973  ABSTRACT  Appl. No.1 424,266 A wall structure is described which contains joints sealed by a system operating in accordance with the rain screen principle. Adjacent panels have facing  US. Cl 52/396, 52/471 edg grooves and an air Sealing member between the  lllt. Cl. E04B 1/68 panels on the interior Side thereof A rain Screan f  Field of Search 52/471, 470, 396, 403 fie, retained in only one of Said grooves spans the gap between the grooves with a flexible screen and coop-  References cued erates with the air sealing member to create interiorly UNITED STATES PATENTS of the screen a pressure equalization chamber. Prefer- 3,205,629 9/1965 Rumley et a1 52/396 ably th r are also means to urge the screen into 3,526,071 9/l970 Watanabe 52/396 X contact with outer sides of the two grooves. 3,691,708 9/1972 Firnkas r 52/403 X 3,742,669 7/1973 Mansfeld 52/396 6 Claims, 7 Drawmg Figures U.S.;Patnt Nov. 18,1975 Sheet1of2 3,919,820
US. Patent Nov. 18,1975 Sheet20f2 3,919,820-
WALL STRUCTURE AND DEVICE FOR SEALING THEREOF BACKGROUND OF THE INVENTION The invention herein relates to a novel wall structure and a device for sealing the joints therein. More particularly, it relates to a structure intended to serve as an exterior wall of a building, where one side will be exposed to weather, to a device for sealing the joints in the exterior wall against the weather, and to the sealing system commonly referred to as the rain screen principle.
Exterior walls of buildings are often constructed from a plurality of individual panels placed vertically or horizontally in edge-to-edge relationship. At the joints where the edges of adjacent panels adjoin, gaps usually occur, occasionally because of less-than-perfect matching of the adjoining edges or poor workmanship in construction. More commonly such gaps are deliberately left in the wall to permit expansion and contraction of the individual panels with changing temperatures. These gaps must be sealed by suitable weathertight means to prevent the wind, rain, snow and other inclement weather to which the exterior of the wall is exposed from penetrating to the interior side of the wall. Many types of sealing means have been proposed and- /or used at one time or another. Among these is the system which operates on the well-known rain screen principle. This principle is described in detail in Aluminum Curtain Walls, volume 2, published in 1971 by the Architectural Aluminum Manufacturers Association of Chicago. In such a system an inner seal provides the actual air seal. Exteriorly of this inner seal is a baffle extending between the two adjacent panels. Between the baffle and the seal is an air space known as a pressure equalization chamber. In the absence of the equalization chamber, the moisture would easily pass the baffle and penetrate the seal (or between the seal and the panel edge) because of the pressure differential between the interior and exterior sides of the wall. With the equalization chamber formed by the presence of the baffle, however, the pressure differential driving force for moisture penetration past the baffle is virtually eliminated. Thus only minor leakage of moisture past the barrier occurs, and the inner seal becomes virtually weather-tight since it can be designed for optimum air sealing and does not have to simultaneously function as a water seal.
A number of different baffle designs have been proposed. Some, such as certain of those shown in the aforecited Aluminum Curtain Walls article, are suitable only for sealing horizontal openings. Others, such as rigid metal strips, as satisfactory only for vertical openings. Further, many suffer from the disadvantage that they can be emplaced only after erection of the wall, and necessitate complicated assembly procedures. Thus, for instance, rigid metal strips cannot be placed in wall grooves in the adjacent panel edges other than from the ends of the assembled panels. Thus, each long metal strip must be inserted from the end of the panels and run through the entire length of the panels. This is a very time-consuming process, and often results in serious bending or kinking of the long thin strips. Also, since the rigid metal strips fit only loosely into the wall grooves, they cannot be emplaced when only one panel 2 is erected; rather both panels must be in place to form an enclosed groove to hold the strip.
Complex assembly requirements for use on the job site are expensive, time-consuming and lead to many 5 improperly constructed walls which do not adequately seal against weather. It would therefore be very desirable to have a rain screen baffle which could be incorporated into a wall panel by the factory which produced the panel. On the job site the panel could then be erected and the baffle would simultaneously be placed without any separate effort by the workmen. Also, by being carefully incorporated under factory rather than field conditions, the proportion of misaligned or otherwise faulty baffles would be substantially reduced.
Alternatively, where field assembly is planned, it would be desirable to have a baffle which could be easily installed. It would be especially desirable to have a baffle which could be attached to an emplaced panel and be retained in place solely by that panel. In this way vertical baffles could be put up on the edge of a vertical panel prior to the emplacement of the adjacent panels.
IT is therefore an object of this invention to provide a novel wall structure in which the joints between adjacent panels are easily and securely sealed and baffled during construction.
It is also an object of this invention to define a baffle device which may be easily handled, readily installed, and which will remain in place without supplementary support.
It is further an object of this invention to provide a baffle device which maintains continuous and positive operation under all normal conditions of expansion and contraction of the wall structure.
It is further an object of this invention to provide a baffle device which may be attached to a panel on the job site or at the factory.
BRIEF SUMMARY OF THE INVENTION The invention herein includes a wall structure suitable for use in weatherexposed locations which comprises: a first wall panel a second wall panel in edge-toedge adjacent relationship to the first wall panel, substantially coplanar therewith, and spaced therefrom, whereby a gap is formed between the facing edges of the panels; each of the panels having a longitudinal groove in the edge adjacent to the other panel, the two grooves thereby being in facing edges and substantially opposed to each other; an air sealing member attached to the interior portion of the panels and spanning the gap therebetween; and a baffle member having means securing the baffle member in one of the edge grooves, and a flexible screen extending across the gap between the panels exteriorly of said air sealing member whereby a pressure equalization chamber is formed between said air sealing member and said screen. Preferably the structure also includes means associated with the baffle member to urge the flexible screen into contact with the exterior of each of the two grooves.
The invention also comprises a flexible baffle device for use between two adjoining sections of wall, wherein the facing edges of the adjoining wall sections each contain a longitudinal groove, which comprises: means to secure the baffle device in one of the grooves and a flexible screen which extends into the facing groove. The device preferably also contains means to urge the screen into contact with the exterior sides of both grooves.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective sectional view of a small portion of a wall structure, showing the adjoining edges of two adjacent wall panels and illustrating the use of the sealing system of this invention to seal the gap between the adjacent sections.
FIG. 2 is a sectional plan view showing the joint between two adjacent wall sections and the sealing system a baffle device of the present invention in place therebetween. The Figure shows in solid lines the sealing configuration with the wall panels in their contracted state; i.e., with the gap between them at its widest, and in phantom lines the configuration with the wall panels in their expanded state; i.e., with the gap between them compressed to its smallest width.
FIG. 3 is similar to FIG. 2, and illustrates another embodiment of the baffle device of the present invention.
FIGS. 4a and 4b illustrate in section still another embodiment of the baffle device and its means of emplacement and retention.
FIG. 5 illustrates in section still another embodiment of the baffle device of this invention and its method of retention.
FIG. 6 illustrates in section yet another structure of this invention, this being an embodiment in which the screen and the retention means are separate apparatus rather than being merged into a single unit, as are the embodiments in FIGS. 2 and 3.
DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS tion of the wall structure which is actually exposed to the elements or which is the nearest to the exposed surface of two or more comparable portions. In FIGS. 1-3 and 6 of the drawings, the weather side is designated by the large arrows. In other words, the inclement weather is directed against the wall structure from the direction indicated by the arrows.
The wall structure of this invention (generally designated 2) comprises several principal parts: a first wall panel 4, a second wall panel 6, a baffle 8, an inner seal 9, and a pressure equalization chamber 11 (which is formed by the boundary surfaces of the other parts). The wall panels and grooves illustrated in the Figures are shown in vertical configuration. However, it will be understood that the principle and operation of the system of this invention are the same for a horizontal configuration, and all comments herein are equally applicable thereto. The wall panels 4 and 6 contain in their adjacent edges respectively grooves and 12. Ordinarily, each groove will extend the full length of the edge of the panel. The fact that the grooves do not extend the entire length or height of the panel does not affect the present invention, however. Conveniently, both of the grooves will have similar or identical crosssectional shapes. Such a configuration is preferred for it permits the baffle device 8 of this invention to be inserted into either groove at the choice of the workman. Where the grooves are of substantially different crosssectional shapes, it will usually be found that the base 4 portion of a given baffle will fit satisfactorily only into one of the grooves.
The wall panels 4 and 6 4ay conveniently be 6f any material suitable for exterior building use and having an edge a thickness sufficient to incorporate the grooves 10 and 12 therein. Wood, exterior grade sheet rock, concrete and the like are all suitable. Also suitable are wall structures wherein the edges are sufficient thickness although the panel facings may be of thin sheet material. Thus, sheet metal or plastic panels with wooden edges, as shown in FIG. 3, and similar structures are also suitable. A preferred type of panel is made of extruded asbestos-cement. Extrusion offers the advantage of the ability to form the edge grooves at the time that the panel itself is formed, thus eliminating any necessity for a separate groove forming step. Typical of the extruded asbestos-cement panels preferably used in the wall structure of this invention are those marketed under the trademarks CORSPAN and FACESPAN by the Johns-Manville Corporation.
On the interior side of the wall structure 2, inwardly of the opposing grooves 10 and 12, is air sealing device 9. As shown herein, this is an elastomeric strip of material running the length of the gap between the panels, and being joined at all points to the opposite edge faces 13 and 15 of wall panels 4 and 6. Any resilient elastomeric material will serve for sealing device 9. Since a small amount of mositure ordinarily does pass beyond baffle 8, air sealing device 9 should be of water resistant material. It does not act as a water seal, of course. It may be joined to faces 13 and 15 by conventional cements or adhesives.
An important component of the wall structure of the present invention is the baffle device 8. This comprises means to secure the device in a groove such as 10, and a screen to span the gap between panels 4 and extend into the facing groove, such as 12, to form pressure equalization chamber 11 outwardly of air sealing device 9.
Two preferred embodiments are shown in FIGS. 2 and 3, with that in FIG. 2 being the more preferred. In these embodiments, the retention means used to secure the baffle 8 in the groove (in this case 10) comprises resilient base 14. The flexible screen which is also part of the one-piece unit is designated 16. The base 14 is usually relatively rigid as compared to the screen 16. In the embodiment shown in FIG. 2, the base portion of 14 must be sufficiently rigid to be retained in the groove 10 during shipping of the panel, assembly of the wall and in service thereafter. However, it must also be sufficiently deformable and resilient that it can be inserted into the groove 10 past retaining constrictions 18 and 20 and thereafter expand to fill the back portion of groove 10. A number of materials will serve satisfactorily for such a base section, having the appropriate combination of deformability, resilience and'stiffness. Typical of these are many of the natural and synthetic rubbers as well as a variety of other elastomeric materials.
Alternatively, as shown in FIG. 3, the base portion may be made of a relatively soft material (such as an elastomer of appropriate properties) inserted into' place in groove 10 and then filled with a rigid stiffening material 22 such as a foamed plastic to maintain the shape of the base section. In another embodiment, shown in FIG. 5, groove 10 has no restraining constrictions of the type used for a friction fit of the base section. Rather the base portion is inserted into a straightsided groove and then a cover plate 17 'i s'attached" to the end of wall section 4 as by-bolt '19 to holdthe'baffle 8 in position. Because of the added components and extra operations required for assembly, these embodiments are not preferred. In the embodiment of FIGS. 1 and 2, the groove 10 is of an hour glass? shape and the baffle 8 is held in the groove by force fit, with the base 14 being deformed sufficiently to be inserted past the ridges and 18 and then resiliently self-expanding in the inner portion of groove 10 in a trapezoidal shape to completely fill the groove and maintain a frictional contact with the surfaces of the groove. Reference is here made (for brevity) only to groove 10. It will be of course understood that where grooves 10 and 12 are essentially alike, the comments herein to groove 10 apply equally to groove 12, and vice versa in the discussion of the screen 16. The choice of assembly positions is simply one of convenience to the installer.
In another embodiment, of FIGS. 4a and 4b, groove 10 is usually straight, but may have a slight taper. Base 14 is serrated on its outer surface, having teeth or fins 21 which project to a width greater than the width of groove 10. In use the baffle 8 is forced into groove 10 and teeth 21 compress to lock into the groove.
In still another embodiment utilizing two separate pieces for the screen and the retention means, screen 16 is a flat flexible strip of material extending into grooves 10 and 12. It is held in place in groove 10 by spring 23, shown here as a curved strip of metal or rubber. Other types of springs, such as coil, springs, can also be used.
The screen 16 is a single strip of flexible material which is resistant to the various weather phenomenon to be encountered. The material must have sufficient flexibility to bend readily and change shape (as designated at 16 and 16 in FIGS. 2 and 3) with the expansion and contraction of the wall. It must, however, have sufficient stiffness to resist being folded back by winds that blow against the wall. Suitable materials are many elastomers or flexible metals, although the latter are less preferred because of their cost and their susceptibility to being bent or dented during handling. The screen 16 extends completely across gap 25 and into both grooves 10 and 12. Preferably screen 16 is of sufficient breadth to extend completely across the breadth of grooves 10 and 12 to approach or contact the back surface of groove 12 as indicated at 26. An excess of material may be used to give screen 16 a convex shape to bias screen 16 into contact with the outer surfaces of grooves 10 and 12. In other words, the breadth of screen 16 should preferably be somewhat greater than the distance from the point of connection with base portion 14 to contact with the back wall of groove 12 when the wall is in its most contracted position; i.e., when the gap between adjacent sections 4 and 6 is at its greatest. Preferably, the end or tip 28 of leg section 16 will be rounded in cross-section, e.g., bulbous or hooked as shown respectively in FIGS. 2 and 3. This aids the tip of screen 16 in sliding along the back surface of groove 12 and prevents it from being snagged on a surface irregularity of the groove. When the wall is in its most fully expanded condition, i.e., when the gap is at its smallest, flexible screen 16 is curved down to the position shown as 16 in FIGS. 2 and 3. In this configuration, contact with the outer walls of grooves 10 and 12 is possible in all intermediate positions between the maximum contraction and expansion.
In the configuration shown in FIG. 3 the screen "16 extends from the middle of the base 14. This is less preferred butmay be used where expected wind velocities are moderate. r I
As shown in FIGS. 2 and 6, the tip of screen 16 need not touch the back end of groove 12, as long as the screen 16 extends substantially into the groove and has sufficient resilience not to be unduly bent back by the wind to close off chamber 11. It will also be noted that in some configurations, such as that shown in FIG. 46, the screen portion in groove 10 is at least in part coextensive with a portion of base 14, as indicated at 27.
The means urging screen 16 into contact simultaneously with the exterior sides of grooves 10 and 12, as illustrated in FIGS. 1 and 2 is ordinarily and preferably the resiliency in flexible screen 16, which makes screen 12 try to assume a straight configuration, thus urging the screen outwardly. Alternatively, a flexed metal backing, such as metal strips, or similar strips embedded in the screen 16, or the like may be used.
The baffle 8 extends the full length of the gap between panel 4 and 6. Throughout its length screen 16 is in contact with the inner surface of groove 10 and the outer surface of groove 12. Contact need not be continuous at all times over the entire length, but will be generally maintained.
Assembly is readily understood from the drawings. The baffle 8 is inserted into groove 10 and held by the retention means. This can be accomplished in the field, either with the panel erected or in a storage area, or in the factory where the panel is produced.
What is claimed is:
1. A wall structure incorporating the rain screen principle and suitable for use in weather exposed locations, which comprises:
a first wall panel;
a second wall panel in edge-toedge adjacent relationship to said first wall panel, substantially coplanar therewith, and spaced slightly therefrom, whereby a gap having an outward portion and an inward portion is formed between the facing edges of said panels;
each of said panels having a longitudinal groove in the edge adjacent to the other panel, the two grooves thereby being in facing edges, substantially opposed to each other, and dividing said gap into 7 its respective outward and inward portions;
an air sealing member attached to the inner portion of each of the opposed edges inwardly of the grooves therein, and spanning the inward portion of said gap therebetween;
a baffle device comprising retention means for securing said baffle device in one of said grooves and a flexible screen spanning said gap and extending into the other of said grooves; said baffle device also comprising means for urging said flexible screen into contact with the outer sides of both of said grooves; and no portion of said baffle device substantially extending into that portion of said gap which lies outwardly of said grooves; and
said flexible screen and air sealing member cooperating with said grooves to form a pressure equalization chamber, whereby a substantially weathertight seal is created across said gap and the penetration of moisture to the interior of said wall structure is prevented.
8 said baffle device which is serrated and the serrations serve to retain said baffle device in said groove.
5. The wall structure of claim 1 wherein said baffle device is retained in said groove by a rigid core filing the hollow base of said baffle device.
6. The wall structure of claim 1 wherein said urging means comprises the resilience of said flexible screen. l