US3895469A

US3895469A - Roof and wall panel system

Info

Publication number: US3895469A
Application number: US377362A
Authority: US
Inventors: John R Kapitan
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-07-09
Filing date: 1973-07-09
Publication date: 1975-07-22
Anticipated expiration: 1992-07-22

Abstract

A panel system of structural foam modules for finish covering and weatherproofing roofs and exterior walls. The panels are fastened to sheathing or furring strips with concealed screw shank nails and structural adhesives. The modules are mechanically interlocked with a tongue and groove and rabbeted fastening step connection. A separate flat reinforcing bar is internally interleafed in the interstice of the tongue and groove joint. The use fo the bar is optional. A vertical joint divider acts as a joint cover. The divider includes a batten plate projecting integrally from a thin transverse body which is shaped like the panel module itself and is locked into the mating contours of the panel joints. Panel backs are flat but panel faces are inclined to provide an overhanging lower interlocking edge to secure and protect not only the joints below, but also the top edge of the batten plate of the vertical joint divider. For weatherproofing, all vertical and horizontal joints are sealed with plastic adhesives during assembly. The panels have a constant cross-sectional shape and therefor may be trimmed or shortened at either end without violating the integrity of their joints. The panel modules have an opening traversing their lengthwise dimension; in the assembled wall the openings form continuous internal passageways for wiring, piping, or other line services.

Description

United States Patent [1 1 Kapitan July 22, 1975 1 1 ROOF AND WALL PANEL SYSTEM {76] Inventor: John R. Kapitan, 9882 W. Kentucky Dr.. Lakewood. Colo. 80226 221 Filed: July 9, 1973 211 Appl. No.: 377,362

[56] References Cited UNITED STATES PATENTS 1.480.283 1/1924 Meyer 52/541 2.1831190 1/1940 Young 52/459 2,231.006 2/1941 Harshhergcr 52/539 2.522.067 9/1950 Sperry 52/420 2.620.519 12/1952 Engclbach 52/541 2.897.930 8/1959 Primich 52/468 3.217.453 11/1965 Medow... 52/539 3.740.909 6/1973 Stinncs 52/595 3.760.546 9/1973 Martin 52/468 3.789.556 2/1974 Skinner 52/539 FOREIGN PATENTS OR APPLlCATlONS 204.487 10/1923 United Kingdom 52/468 576.161 3/1924 France 52/436 221.279 4/1910 Germany. 52/468 496.608 7/1954 ltaly 52/541 Primary Examiner-Ernest R. Purser Assistant Examiner-H. E. Raduazo Almrney, Agent. or FirmWheeler. Morsell, House & Fuller [57] ABSTRACT A panel system of structural foam modules for finish covering and weatherproofing roofs and exterior walls. The panels are fastened to sheathing or furring strips with concealed screw shank nails and structural adhesives. The modules are mechanically interlocked with a tongue and groove and rabbeted fastening step connection. A separate flat reinforcing bar is internally interleafed in the interstice of the tongue and groove joint. The use fo the bar is optional. A vertical joint divider acts as a joint cover. The divider includes a batten plate projecting integrally from a thin transverse body which is shaped like the panel module it self and is locked into the mating contours of the panel joints. Panel backs are flat but panel faces are inclined to provide an overhanging lower interlocking edge to secure and protect not only the joints below. but also the top edge of the batten plate of the vertical joint divider. For weatherproofing, all vertical and horizontal joints are sealed with plastic adhesives during assembly. The panels have a constant crosssectional shape and therefor may be trimmed or shortened at either end without violating the integrity of their joints. The panel modules have an opening traversing their lengthwise dimension; in the assembled wall the openings form continuous internal passageways for wiring, piping, or other line services.

8 Claims, 13 Drawing Figures SHEEI PATENTED JUL 2 2 1 .1 mr lWAK 6 r/ ////////////////\A \uh/ W ////////WV/N M IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII II PATENTED JUL 2 2 I975 SHEET PATENTEDJUL22|915 3 895 469 Fig.10

ROOF AND WALL PANEL SYSTEM BACKGROUND OF THE INVENTION More building components and subassemblies are needed which are based on the use of plastics-asplastics and not simply on the use of plastics as imitations of customary building materials. New plastic products that fully utilize man-made structural thermoplastic and thermoset materials can help raise accepted construction procedures to a higher level. help pre serve our wood supply. and reduce construction costs. The new plastics building materials and assemblies now produced are not necessarily representative of inferior low-cost housing. but are in most instances a superior means for providing rapid. efficient. factory production reliability for industrial. commercial. and residential construction.

Exterior roof and wall coverings utilizing thermoplastic and thermoset structural foams are useful in building construction especially because of their built-in insulating values. Substantial loss of heat or cooling takes place through the roofs and walls of buildings which are heated above or cooled below the temperature of the outside air and the rate of loss depends. other factors being constant. on the conductivity of the roof or wall material. The roofand \vall panel of this invention is directed to the improved use of structural foams for roof and wall coverings.

SUMMARY OF THE INVENTION The roof and wall panel system of this invention includes a horizontally interlocking panel module and a separate joint divider which protectively covers the vertical joints. As the panels are assembled. weatherproofjoints are formed along all vertical and horizontal junctures. The upper horizontal panel edges are rah bcted and grooved to fit into the complementary contours of their lower horizontal edges. In juncture. the horizontally rabbeted step joint has the double purpose of providing a concealed fastening step and a weatherproofing joint which is additional to the horizontal tongue and groove joint. The joint divider has a batten plate cover which is integral with the dividers panelconformed body. Panel back and divider back are llat for flush installation against sheathing or furring. Panel face and divider face. however. have a downwardly sloping front profile for providing an overhanging and notched lower edge to protect the horizontal joints below. The horizontal edges of both panel and divider thus have the same symmetrical disposition. As tops and bottoms are titted edge to edge. the panels and dividers are securely joined and overlapped by their mat ing contours. The components of the roof and wall panel system are made of rigid structural foam thermoplastic or thermoset plastics of appropriate densities. The basic rectangular panel module has an opening coursing through its lengthwise dimension. In the assembled roof or wall covering. the openings within the panel modules form continuous passageways for wiring. piping. and other services.

A separate metal reinforcing bar is provided to span two or more modules and to bridge the joints between them. This flat rectangular bar may be used selectively for reinforcing stress areas. The bar is positioned and concealed between the planar faces of the horizontal tongue and groo\e joint. When the reinforcing bar is not used. a longitudinal space is left vacant within the horizontal tongue and groove joint without detracting from the joint integrity.

The panel modules are attached to adjacent structure with self-tapping screws. screw shank nails. or adhesive 5 bonding. The interlocking vertical and horizontal joints are also adhesively sealed during assembly to provide effective protection against the entrance or escape of moisture and air. Because it has a constant crosssectional shape. the panel module may be trimmed or shortened by cutting at either end without affecting the joint integrity.

The roof and wall panel system further includes ausiliary panels in the form of outside corners. inside corners. shallow flat-bottom mounting bases. and edging l5 caps.

A modified embodiment of the vertical joint divider is provided by a vertical flush joint cover comprising an L-shaped flat strip that fits under the overhanging edge of the upper adjacent panel module and encompasses the overhanging edge of the lower adjacent panel module as the cover is placed over the top ofa vertical joint between two panel modules to seal it against the weather. The flat joint cover is retained in place by a clamping action at the top and bottom frontal edges of the adjacent panels and may be permanently secured with adhesive bonding. Like the vertical joint divider. the flush joint cover will protect a vertical joint wherever it may fall along a horizontal course because ofthe continuous protective feature of the coacting. outwardly projecting panel edges.

It is a primary object of this invention to provide a lightweight but structurally strong and weatherproof roof and wall covering of structurcal foam panels that can be assembled quickly at the job site and that may be used equally well for roofs and walls.

It is another object to provide a lightweight roof and wall covering that is especially resistant to high winds because of its improved interlocking and fastening systern.

It is another object to provide a roof and wall covering that provides effective insulation at the joints against air and moisture penetration.

It is another object to provide a lightweight roof and wall covering with a stress resistant unity which will allow the use of building structures with lighter weight beams. columns. and framing members.

The aforementioned objects and further objects. ad vantages. and details of the invention will be more clearly perceived from the following specifications of preferred embodiments of the invention and related drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a roof and wall panel with inclined face. a vertical joint divider. and a rectangular reinforcing bar. The figure further illustrates the panel's erection and self-positioning features in con junction with the nest succeeding panels.

FIG. 2 is a perspective view of a vertical joint divider seen from the rear.

FIG. 3 is a transverse vertical cross section taken through a segment of an erected roofor wall panel covering and showing the continuous horizontal joints cf fected by a vertical joint divider fitted between adjacent panel modules. Also shown is the axially concealed metal bar reinforcing the stacked units and their interlocking joints and the unoccupied space that oc- (ill cars within the tongue and groove joint when a reinforcing bar is not used.

FIG. 4 is a transverse vertical cross section similar to FIG. 3 but showing adjacent upper and lower panel modules.

FIG. 5 is a perspective view of a 90degree inside corner module.

FIG. 6 is a perspective view similar to FIG. 5 showing a 90-degrec outside corner module.

FIG. 7 is a perspective view of two sections of a pcrimeter channel base (mounting base) connected by a truncated vertical joint divider.

FIG. 8 is a perspective view of a perimeter channel base similar to FIG. 7 but in the form of a )(I-degree outside corner.

FIG. 9 is a fragmentary perspective view of a perimeter edging cap.

FIG. III is a front elevation of a wall or roofcovering constructed out of the roof and wall panel.

FIG. II is a perspective view of a vertical flush joint cover as seen from the rear.

FIG. I2 is a perspective view of two roof and wall panel modules butted together end to end. forming a flush vertical joint. The figure also shows the weathen proofing of the joint by an installed flush joint cover. including its lower edge coupling.

FIG. I3 is a transverse vertical cross section taken through a segment of an erected roof and wall panel covering. showing adjacent upper and lower panel modules and their continuous horizontal joints. The fig are further shows a vertical flush joint cover clamped under the upper overhanging edge and over the lower overhanging edge of adjacent panels.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention. the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other physical structure. The scope of the invention is defined in the claims appended hereto.

Like parts are given the same reference characters in the several views.

Based on the 4inch unit of measurement and multiples of this unit to conform with established building material sizes. a suitable set of dimensions for the panel module of this invention may be 24 inches wide. I2 inches high. with 3 inches at the top thickness and 3% inches at the bottom. All components of the roof and wall panel system are preferably molded out ofintegral solid skin structural foam plastics such as polyurethane rigid foam. impact grades of polystyrene foam. and polypropylene rigid foam. Use of the same material for both panel Ill and the vertical joint divider 20 will insure that all units have close to the same coefficient of expansion to avoid problems caused by thermal cycling. The structural foams have a solid skin separated by a rigid low-density cellular core. By virtue of their closed-cell structure. the commercially available structural foams have permanent resistance to water penetration and retain their high insulation value indefinitely. They also have other qualities desired in roof and wall construction materials. for example. high compressive strength. the capacity to withstand exposure to heat and cold, non-attraction to vermin. termites. bacteria. or insect pests. and ready availability in (all a self-extinguishing lire-protective rating. Different densities of structural foam may be specified. from about 2 pounds to 50 pounds per cubic foot. depending on the rigidity and strength required in a particular application.

The panel module and other components of the roof and wall system may be molded as individual parts on conventional structural foam molding machines. Because of its uninterrupted longitudinal configuration. the basic panel module It) also may be fabricated by extrusion rather than by the individual closedmold process. In the former case. the panel module I may be fabricated on commercially available structural foam extrusion equipment to be subsequently cut into selected unit lengths.

As depicted in the drawings. the roof and wall panel may be molded or extruded with or without rectangular axial openings 6i. Hollow panels are preferred because of the advantages obtained from the resulting lighter weight. material savings. and the use of the rectangular openings 61 as concealed wall or roof passageways for piping. wiring. and various service lines.

As shown in FIG. I. positive weatherproof tongue and groove joints 30 combined with rabbetcd step joints 34 overlap and interlock both the upper and lower horizontal edges of the basic panel I0. For augmenting the security of the horizontal joints. the outer face surface of the basic panel III slopes downward diagonally to form an overhanging edge that protects its lower horizontal edges. During the installation of a roof or wall covering. adjoining panels II) are positioned and interlocked horizontally by the mating tongue and groove joints 30 and rabbetcd step joints 34 on their upper and lower edges. In particular. the rabbetcd step joint 34 is composed ofa longitudinal recess 35 cutout at the lower rear of the panel module Ill and a complementary raised fastening step 36 projecting upward from the upper rear of the panel module I0. As illustratcd in the drawings the raised edge provides a support or nailing step 36 for securing the panel module II] to adjacent structure. The next succeeding panel in the layer above overlays and interlocks the horizontal joints below and thereby conceals the mechanical fasteners. The panels may be attached to adjacent struc ture by adhesive bonding of their flat backside or inner surface I2 or by nails in the raised nailing edge 60 (FIG. As each layer of panels is strung out. a verti cal joint divider is set against the end surface I3 (FIG. I ofeach panel Ill. The vertical joint divider 20 includes a batten plate 21 (FIG. I) integrally projecting at right angles from the dividers thin body 22 whose transverse shape conforms in every detail with the pan els cross sectional shape.

The laterally extended face plate or batten plate 21 on each side of the joint divider. in covering a vertical joint. may overlap by a narrow or wide margin depending on the degree ofjoint protection required. A wider batten plate would increase the sealing area to insure a greater degree of airtight and water-tight surface covering.

As shown in FIGS. I. 2 and 3. a vertical joint divider 20 contacts adjoining panels and is retained in place in the wall or roof assembly by the horizontal tongue and groove joints and rabbetcd step joints at the upper and lower edges ofeach layer of installed panels. As two panel end surfaces are abutted against the vertical joint divider 20, the vertical joints thus formed are protected by the integral batten plate 2] which extends laterally from each side of the divider 20 to cover the \ertical joints on the underside. Further. the panel 10 is equipped at its lower horizontal frontal edge with an elongated notch 37 for securing the vulnerable top horizontal edge of the batten plate Zl. Because the panels H) are mounted with breaking joints. the installed vertical joint divider 20 normally falls at the midpoint ofthe panel 10 in the layer above and at the midpoint of the panel in the layer below. The elongated notch 37. however. covers and protects the top edge of the batten plate 2l wherever it may be positioned. As the panel in the succeeding layer above is set in. it fits over and covers the top edge of the batten plate 2| below it for an effective vertical joint seal against the weather. The flat vertical end surfaces 13 (FIG. 1 l of two adjoining panels It) are thus provided with joint protection at their point of contact with the joint divider 20. FIGS. 3 and 4 show a transverse vertical cross-sectional view taken through a segment of an assembled roof or wall panel covering embodying this invention. The figures illustrate that the notched lower edge 37 of the panels inclined front profile l l provides a protective cover to the underlying top edge of the batten plate 2l regardless of the order in which the basic panel modules [0 and the vertical joint dividers may fall.

The tongue and groove joints 30 are reinforced with a separate. intcrlcafcd. solid. elongated flat metal bar that sits astridc two or more panel modules 10 and bridges the vertical joint between horizontally adjoining units to provide a stress-resistant brace. As shown in FIGS. l. 3 and 4. the longitudinal groove 32 of the tongue and groove joint is twice the depth required to accommodate the mating tongue 3]. The other half ofthe groove's depth may be used to house and conceal the flat rectangular reinforcing bar 25. The use of the reinforcing bar 25 is optional. Where it is not required or installed. the unused half-depth 33 in the groove 32 remains as a \acant space. as shown in FIGS. 3 and 4. The bar 25 may also be fabricated of lighter weight structural grade material such as an epoxy-impregnated fiberglass laminated strip.

Either mechanical fasteners or adhesive bonding or both means of fastening may be employed to secure the roof and wall panels directly to sheathing or l'urring strips. Panels molded of structural foam can be assem bled by the same techniques as that used for wood by virtue of the structural foam's good nail and screw holding power. For mechanical fastening. selftapping screws or screw shank nails are desirably selected. Fastening with adhcsi c bonding alone permits a more uniform distribution of stresses through the assembled panel area. In most instances mechanical fastening will not be needed if proper structural adhesives are used which are capable of uniting panel and adjacent structure by surface attachment. The usual hand-operated or power-drive woodworking tool may be used on the job for fitting the structural foam panels around vents and projections.

Although the roof and wall covering herein disclosed will be strongly resistant to wind stresses. it will not be air and moisture proof without the application of adhesi\c bonding between all assembly joints. By reason of their tight jointing. the unsealed panel joints will proide a strong barrier to the movement of air and moisture. Adhesive bonding. however. will desirably provide positive protection in this respect. The choice of adhesives to be used will also affect the joint efficiency. For example. a resilient adhesive bond will additionally help to accommodate for differential movement due to thermal expansion and contraction of the building structure or through deflection of floor or ceiling under loading. Many types and grades of adhesives are commercially available. With proper selection of the adhesive for over-all assembly and joint sealing. the molded structural foam panels can be bonded together for maximum insulation values.

The roof and wall panel [0 may be initially installed over a shallow flat-bottomed perimeter mounting base 40 (FIG. 7). The top edge ofthe mounting base 40 has the same tongue and groove configuration and dimen' sions as that of the top edge of the panel module [0. The base may be in the pattern of a straight longitudinal section 40 or a 9(l-degree angled corner 4] (FIGS. 7. 8). The mounting base is desirably installed with structural adhesives over projected wall lines or roof edges. Flat or shed. gable. and gambrel type roofs. that is roofs with sloping sides without valleys or hips. are most suitably covered with the roof and wall panel. The roof surface. however. should have a minimum slope of about an inch per foot to obtain positive drainage. The mounting bases 40 are joined vertically in the same manner as the panel modules 10. The vertical joint divider 20. for this purpose. is truncated to bring it to a height equivalent to that of the base 40. As illustrated in FIG. 7, the truncated joint divider 23 has an integral batten plate 24 and the same function as that of the pa nel-size version.

The panel module 10 also may be fabricated in the angled shape of a Ml-degree outside corner 50 and a Ml-degree inside corner 51 (FIGS. 5, 6 The horizontal edge joints of these corner pieces are exactly the same as those of the basic panel module Hi. The installation of the corner shapes as a wall covering is similar to that of the basic panel 10. By eliminating exposed corner joints. the corner shapes 50. 51 provide positive weatherproof corners. assure a clean appearance. and simplify the installation procedures. The basic panel 10 also may be molded to fit around acute angles. obtuse angles. and curves (not shown). A perimeter edging cap 42. shown in FIG. 9. is also provided for use in bringing the top layer of assembled panel modules [0 to a flat surface. The bottom edge of the edging cap 42 has the same joint configuration and dimensions as that of the bottom edge of the panel module 10.

FIG. 10 shows the appearance of a fragment of the assembled roof and wall panel covering. The outer roof or wall surface shows an uncluttered appearance because the fastenings are concealed. The batten plate 2| surface projections. in marking the vertical panel joints. add heft to emphasize strong architectural shadow lines.

FIGS. ll-l3 illustrate a modified embodiment of the vertical joint divider. ln this version. a flat. L-shaped flush joint cover with a flanged lower edge 8| provides weatherprooling for the vertical joint 82 between horizontally adjacent panel modules 10. Because the flush joint 80 may be installed after the panel modules [0 have been erected into a roof or wall covering. it is feasible to use either a top-to-bottom or a bottom-totop assembly procedure.

In the use of the vertical joint divider 20. two panel end surfaces are abuttcd against opposite sides of the vertical joint divider 20 to close the vertical joint be- 7 tween horizontally adjoining panels modules. In using the flush joint cover 82. however. two panel end surfaces are abutted flush against each other. The resulting vertical joint 82 is then weatherproofed b the Hush joint cover 80 by l) fitting the flanged coupling 81 of the cover's bottom into the notch 37 formed it the lower overhanging edge of the installed panel l0. and (2) sliding the flush joint cover 80 upward until it is clamped by the lower overhanging edge of the upper adjacent panel ltl. Both bottom and top of the Hush joint cover till are thus mechanically clamped into place. B coating an adhesive on the back side of the flush joint cover 80 before clamping it into place. a permenent weatherproof vertical joint will be achieved. H0. 13 shows the flush joint cover 80 clamped in place between the overhanging edges of adjacent panel modules Hi.

What is claimed is:

l. A structural panel system comprising a pluralit of structural modules each having an upper edge. a lower edge. two opposed side edges. an inner surface. and an outer surface. the upper edge and lower edge of each module being shaped to provide a tongue and groove joint b which the lower edge of each module may be interfitted with the upper edge of the module immediately below it. and the inner surface of each module adjacent to the upper and lower edges thereof being shaped to provide a rabbeted step joint including a raised step projecting above the upper edge of the mod ale and a recess above the lower edge of said module. said recess being shaped to receive the raised step of the module immediately below it. whercbv each module may be attached to a member adjacent the inner surface of said raised step and the attachment means may be covered by the module immediately above said raised step. and a vertical joint divider between adjacent modules. said divider being shaped to match the crosssectional shape of said modules including said tongue and groove joint and rahbeted step joint (ill 8 whereby said vertical joint divider will interlock with modules above and below said divider said divider having a batten joined at a right angle to the front of the divider and overlapping the edges of adjacent modules to prevent water from entering the vertical joint between said adjacent modules.

2. The combination defined in claim 1 and further comprising a reinforcing bar dimensioned to fit within the groove of said tongue and groove joint. the groove of said tongue and groove joint being deeper than the tongue thereof by a depth at least equal to the depth of said reinforcing bar.

3. The combination defined in claim I wherein the outer surface of each module adjacent the lower edge thereof is shaped to overhang the upper edge of the module immediately below it.

4. The combination defined in claim I wherein the front surface of each module adjacent the lower edge thereof is shaped to overlap the upper edge of any vertical joint dividers immediately below said module to prevent water from entering the vertical joints covered thereby.

5. The combination defined in claim I wherein each of said modules has at least one internal opening therein extending between the two side edges thereof.

6. The combination defined in claim I wherein each of said modules has at least one internal opening therein extending between the two side edges thereof. and wherein each of said vertical joint dividers has at least one opening in the bod v portion thereof positioned to match the openings of the adjacent modules.

7. The combination defined in claim I wherein each of said modules is made of foamed plastic material and wherein the vertical and horizontal joints between adjacent modules are sealed by plastic cement.

8. The combination defined in claim 1 wherein the cross-sectional shape of each module is the same at any point between the two side edges thereof.

Claims

1. A structural panel system comprising a plurality of structural modules each having an upper edge, a lower edge, two opposed side edges, an inner surface, and an outer surface, the upper edge and lower edge of each module being shaped to provide a tongue and grOove joint by which the lower edge of each module may be interfitted with the upper edge of the module immediately below it, and the inner surface of each module adjacent to the upper and lower edges thereof being shaped to provide a rabbeted step joint including a raised step projecting above the upper edge of the module and a recess above the lower edge of said module, said recess being shaped to receive the raised step of the module immediately below it, whereby each module may be attached to a member adjacent the inner surface of said raised step and the attachment means may be covered by the module immediately above said raised step, and a vertical joint divider between adjacent modules, said divider being shaped to match the crosssectional shape of said modules including said tongue and groove joint and rabbeted step joint whereby said vertical joint divider will interlock with modules above and below said divider, said divider having a batten joined at a right angle to the front of the divider and overlapping the edges of adjacent modules to prevent water from entering the vertical joint between said adjacent modules.

2. The combination defined in claim 1 and further comprising a reinforcing bar dimensioned to fit within the groove of said tongue and groove joint, the groove of said tongue and groove joint being deeper than the tongue thereof by a depth at least equal to the depth of said reinforcing bar.

3. The combination defined in claim 1 wherein the outer surface of each module adjacent the lower edge thereof is shaped to overhang the upper edge of the module immediately below it.

4. The combination defined in claim 1 wherein the front surface of each module adjacent the lower edge thereof is shaped to overlap the upper edge of any vertical joint dividers immediately below said module to prevent water from entering the vertical joints covered thereby.

5. The combination defined in claim 1 wherein each of said modules has at least one internal opening therein extending between the two side edges thereof.

6. The combination defined in claim 1 wherein each of said modules has at least one internal opening therein extending between the two side edges thereof, and wherein each of said vertical joint dividers has at least one opening in the body portion thereof positioned to match the openings of the adjacent modules.

7. The combination defined in claim 1 wherein each of said modules is made of foamed plastic material and wherein the vertical and horizontal joints between adjacent modules are sealed by plastic cement.