US 3803786 A
A building which requires a minimum of material is prefabricated by providing a series of prescored glass fibre reinforced double faced corrugated paperboard panels which are folded into rectangular section box beams on site. These box beams, a wooden platform with uprights and a roof ridge beam provide the complete shell for a house incuding the inside walls. Insulation is provided in the box cavity and the assembly can be carried out with unskilled labor using adhesive and stapling devices; prefinished doors and windows can be added as desired. The box beams are thus almost surrounded by a channel of glass fibre reinforcement and T-section splines are placed between channels and bonded to both the webs and base of the channels so that each outside wall and roof comprises an integral glass fibre reinforced shell with webs extending inwardly from the shell.
Claims available in
Description (OCR text may contain errors)
United States Patent 11 1 Schneider 1111 3,803,786 1451 Apr. 16, 1974  Inventor:
 Assignee: Panokraft Corporation of Canada Limited, Quebec, Canada 22 Filed: July 14, 1972' 21 Appl. No.: 271,755
Marvin Schneider, Bryn Mawr, Pa.
 Foreign Application Priority Data May 3, 1972 Canada 141184 [52 us. c1... .,..s2/233, 52/90, 52/631  Int. Cl E04b 1/12, E04b 1/28  Field of'Sear ch 5 2/90, 82, 731, 233, 577, 52/576, 631, DIG. 8; 46/19, 20, l L
[5 6] References Cited UNITEDSTATES PA-TENTS 3,564,785 2/19'71 Kephart....; 52/86 1,883,141 10/1932 Walters 52/630 X Griffith 52/233 2,954,054 9/1960 Shelly 229/93 X 3,387,872 6/1968 Lovullo et a1 52/DlG. 8 2,267,929 12/1941 Lefebure et al. 52/731 2,874,512 2/1959 Joseph et al. 46/25 Primary Examiner-Henry C. Sutherland Assistant Examiner-Leslie A. Braun Attorney, Agent, or Firm-Spencer & Kaye 5 7] ABSTRACT A building which requires a minimum of material is prefabricated by providing a series of prescored glass fibre reinforced double faced corrugated paperboard panels which are folded into rectangular section box beams On site. These box beams, a wooden platform with uprights and a roof ridge beam provide the complete shell for a house incuding the inside walls. Insulation is provided in the box cavity and the assembly can be carried out with unskilled labor using adhesive and stapling devices; prefinished doors and windows can be added as desired. The box beams are thus almost surrounded by a channel of glass fibre reinforcement and T-section splines are placed between channels'and bonded to both the webs and base of the channels so that each Outside wall and roof comprises an integral glass fibre reinforced shell with webs extending inwardly from the shell.
4 Claims, 15 Drawing Figures PATENTEUAPR 16 1974 MEI 2 [IF 7 ATENTEMPR16 m4 (3,803, 786
sum 6 OF 7 PATENTED APR :6 I974 SHEET 7 OF 7 FIGIO SPLINE FOR GLASS FIBER REINFORCEMENT FOR A BUILDING MADE FROM PRESCORED FLAT SHEET MATERIAL This invention relates to a building structure, and a method of erecting such a structure so that there is a minimum of transportation costs in sending the material to site and so that the building can be assembled quickly and easily by unskilled personnel.
In greater detail this invention concerns a building which is made of paperboard. Of .course, paperboard for buildings is not a novel idea but previous constructions have left something to be desired; for example, the materials used have relied upon an exterior finishing operation for structural integrity and weatherproofing. This has meant too much on site work, which is carried out by unskilled personnel, and less in plant manufacture where end product quality can be closely controlled. I
A copending application in the names of Yves Caron and John Stark (US. application Ser. No. 225,808, filed Feb. 14, 1972 and assigned to the assignee of this application) describes and claims a building which is made from folded paperboardbox beams which have a glass fibre channel reinforcement. The base of the channel is always on the outside and the small gaps between the bases of successive beams can be joined by glass tape in a suitable glue so asto make the outside an unbroken reinforcing shell of glass'fibresin resin.
The object of this invention is to complete the glass fibre shell by the addition of a spline member which not only reduces the assembly costs and increases quality by substituting an inexpensive factory built component for a manual wet lay-up technique, but also achieves structure integrity of all the glass fibre reinforcing channel in a wall or roof with one another and the integral shell.
Other inventive features will be apparent on reading the disclosure and claims: the disclosure that follows incorporates the subject matter of the abovementioned copending application in order toeffect a complete understanding of how this invention operates. However, the scope of this invention is defined by the claims.
The claims will be more readily understood after reading the description of the drawings which illustrate, by way of example, a conventionally shaped house and details of how it is constructed.
In these drawings;
FIG. 1 shows a perspective view of a completed house;
FIGS. 2a shows the initial stage of manufacturing a box beam from a sheet of paperboard; FIG. 2b shows a second stage when the box beam is ready for shipment from the plant as a flat panel;
FIGS. 30 and 3b show initial stages of manufacture of an alternative embodiment of the fiatvpanel;
FIG. 4a shows an on site initial stage in the. assembly of a wall or roof portion;
. FIG. 4b shows a wall or roof portion being completed;
FIG. 5 illustrates how a box beam of a wall series is joined to one of a roof series;
FIG. 6 shows the assembly of FIG. 5 being assembled to form the house; e
FIG. 7 shows the assembly of framing members for windows or doors;
FIG. 8 illustrates the ease with which a wall box beam section may be modified on site to form a strong and weather-proof corner for the building;
FIG. 9 illustrates how a similar modification of a roof box beam embraces the end wall box beams;
FIG. 10 shows a typical example of how the roof is finished off at the pitch point;
FIG. 11 illustrates a T-section strengthening device.
FIG. 12 illustrates how the open ends of the roof box section beams are closed so as to prevent entry of rodents and to allow exterior attachments such as eaves troughing.
In FIG. 1 of the drawings the assembly 2 shows a house of entirely conventional appearance with side walls 4 and end walls 6 and a pitched roof 8. The side walls 4 and theend walls 6 can accommodate standard factory built windows 10 and doors l2.
Although this house has an entirely conventional appearance its construction is new because the walls and roof are built of rectangular section paperboard box beams. These beams are prefabricated in a plant as a continuous process which produces a flat suitably scored panel; at the end of the process the flat sheet is cut into one or more standard lengths, depending upon the design of the building, and shipped flat for assembly.
FIG. 2a shows a cross section of the flat paperboard panel 14 having two corrugated sections, with a center layer between them and the top and bottom layers 16, 18 are scored at a number of plates 20, 22, 24 and 26 to facilitate subsequent folding. As will be seen the top layer 16 will become the inside surface or hollow of the box beam and the outer surfaces 18 will be divided into portions 21, 23, 25, 27 and 50 by the scoring. The next stage in the production of the paperboard box beam isto render the material fire-resistant, termite proof and fungus and mildew proof. This is done by any one of a number of processes well known to those skilled in the art. For example, the paper can be made termite proof by adding Dursban (a trademark of Dow Chemical, of Midland, Mich.) to the glue in the corrugating operation as the paperboard itself is being made. Fire retardency is achieved by coating the paper with a solution of N-Silicate such as normal sodium silicate applied to the surface 16. Such a solution with conventional additives and modifiers is a well known article of commerce available, for instance, under the trademark Thermolag a trademark of T.S.I. Corporation of Missouri.
After such treatment the paperboard is coated as indicated at FIG. 2b on surface portions 21, 23 and 25 with a reinforcing layer of polyester and glass fibre applied so as to leave gaps corresponding to the score line. These resin and glass fibre layer portions 28, 34 and 30 respectively are shown somewhat exaggerated in thickness to illustrate these gaps which must be present to allow easy folding on site. The upper paper layer 16 that is on the inside of the box beam to be formed is covered between 20 and 22 by a layer of plastic insluation 32, for example, polyurethane foam.
Thus, FIG. 2b represents one form in which the box beams may be shipped from the plant in the form of flat panels.
It will be understood that there is no critical proportional ratio. The distance between score lines 26 and 20 and 22 and 24 which will give the box beam depth is dependent upon such factors as the length of the roof span and whether snow loads are expected or not. The thickness of the glass fibre-resin reinforcing layer 28, 34, 30 is typically less than that of the paper (although shown equal for illustrative purposes, explained above) and may be in the general region of about onethirty-second of an inch. The actual thickness is less important than the content for the purpose of fixing the splines, and recommended values are l A oz. per square foot of random chopped strand glass mat in anistropic orientation, and 1V ozf per square foot of polyester resin. The thickness of. insulation 32 will depend upon thermal requirements and may be between '7; and 2 inches.
An alternative paperboard layout is illustrated in FIG. 3a. If the beam width and depth are reasonably small, a maximum of say inches and 4 inches respectively, with a 3 inch overlap tag 50, it is possible to produce two panels side by side simultaneously on an 82 inch wide corrugating machine. The two panels shown ready to ship at FIG. 3b are identical, the numbers being suffixed to illustrate the correspondence with FIGS. 2a and 2b; the mirror image effect is illusory and disappears when one panel is turned end for end. The two panels are detached one from the other at cut 51 because a double width panel is difficult to handle on site and is liable to breakage by creasing under its own weight.
FIG. 3b also illustrates the feature that it may be economic to ship the foam insulation separately and fasten it to the panels on site; as its thickness increases the stacking factor of the assembly of FIG. 2 becomes poorer even if alternate panels are inverted.
The method of forming a roof or wall portion on site from a series of box beams is shown in FIGS. 4a and 4b. Firstly, each panel in the series making up the portion is folded inwardly about score lines and 22 so as to form a channel of reinforcing glass fibre and resin 28, 34 and 30 as shown in FIG. 4a. These are stapled together with layers 34 on a flat surface to give proper alignment, and if the insulating foam 32 was not assembled to the paperboard in an in-plant operation, it is fastened at this stage by means of any suitable adhesive stapling devices which have a throat long enough to reach down box beam closing side 27 and which will then close staples 36 through the two adjacent glass fibre and resin layers 28, 30 as well as the paperboard, are readily available. Also, a line of adhesive may be added on adjacent surfaces before they are stapled together.
The box beams are then closed one by one as shown in FIG. 4b, by folding the overlap tag 50 at score line 26 and the inner sidewall 27 at score line 24. These may be tacked at the ends with a conventional type stapler if desired but those staples 39 down the length of the beam are applied with an external clinch type stapler of the type used for making paperboard boxes wherein the staple is closed by jaws operating from the side of the paperboard which the staple first enters. This ensures that the box beam wall 27 stays flat and is not bowed along its length, because of course this wall will become the inner wall of the house and it is not reinforced.
The next stage in the constructions of a typical house is shown in FIG. 5 although for the sake of clarity a single box beam side wall is illustrated generally at 52 and a single box beam of the roof at 54. In the sidewall box beam 52, surface 56 will become the outside of the house and surfaces 58 and 60 represent the underside of the roof beam; 58 will become the caves and 60 will become the inside ceiling of the house itself. The method of joining these two beams is that firstly two L- shaped connector plates 62, 64 typically of one-half inch plywood and typically having an included angle of about 105 are stapled to the inside of webs of beams 52 so that the leg of each projects laterally at this angle to the wall box beam. It may be necessary to remove some of the insulating foam 32 locally to accommodate these connector plates but this can be done fairly easily with nothing more elaborate than a knife. Some foams will compress easily enough to obviate even this minor operation.
Slots 66 and 68 are then cut in the underside of the roof box beam 54 by any suitable means. These should be out within surface 58 so as to avoid any local bulging caused by the connector plates. Thus, the slots should be at least one-half of an inch wide and long enough to allow the whole of the free leg of the connector plate to pass into the interior of the roof box beam.
When these two exemplary beams 52 and 54 have been placed together at the correct angle, the connector plates 62 and 64 are stapled to the webs of beam 54 by reaching through the open end (that is the end that can be seen) of beam 54. It will be understood that the part of roof box beam inner wall 58, 60 which is between the slots 66, 68 and hidden by box beam 52 acts as a firestop by blanking off the hollow of wall box beam 52, thus preventing chimney action. For this reason it is desirable to coat this portion of box beam 54 (and the corresponding portion of its fellows) with the above mentioned fire retardent solution, such as Thermolag before fastening the side wall box beams to the roof box beams. The other box beams in the wall and roof are shown, some in phantom as 72 and 70, to avoid confusion and others, 71 and 73 are in full. The number of beams in the wall and roof sections which are joined together may be 10 or more, depending on handleability and size of individual beam members.
FIG. 6 shows a four beam assembly of the unit of FIG. 5 in place; that is wall and roof box beams have been swung so that wall beams 52, 71, 72 are in a vertical plane and placed on a simple framework. This framework, or skeleton, comprises a floor 74 having a number of wooden blocks, 76, spaced around its per iphery; in addition, there are lumber uprights 78 and 80 which support a roof ridge beam 82 which may be, for instance, two 2-by-2 planks. The number of uprights will depend upon the length and size of the roof lumber beams, only two being shown for clarity.
In the simple attachment shown, roof box beam 54 has a longitudinal extension 84 at one end which is stapled to the 2-by-10; the box beam 52 forming the up right side wall is stapled at its inside surface to a block 76 (which it hides) on the floor 74. It will be seen therefore how the roof of the house and the side wall are assembled.
FIG. 7 shows how door frames and window frames are easily constructed as desired. The outline of the window or door way is marked out, and a saw follows the line marked out; then box beam portions thus isolated are removed. The members forming the window and doorway sides, sill and top members 86, 88, 90, 92 and 94 are stapled into the holes left. It will be understood that the webs of the beams, as indicated by 96, will have to be cut back internally to accommodate horizontal frame members 90, 92 and 94, it is also necessary to cut back the insulating foam 32 for a short distance to accommodate the thickness of the door and window framing material. It will also be clear that each door and window frame material is surrounded on both inside and outside, by a line of staples 98 which are of the double ended nail type as used in making wooden packing crates.
The end walls 6 give no problem other than that of a certain amount of waste; this is because it is preferable to make them a standard length for packaging purposes and allow them to be cut laterally on site so that when they are formed into box beams they will have a bevelled edge which will reach up to the roof surface, and of course each one will be slightly longer than its neighbour.
However, the forming of weather-proof corners and joining the roof to the end wall from such box beam material could present some difficulty and one way to solve these problems is shown in FIGS. 8 and 9 respectively. FIG. 8 shows, in section, side wall box beams 100, 102 and end wall box beams 104, 106 as described above in relation to FIGS. 4 and 5. However, the last side wall box beam member 108 is not closed up or insulated; the inner wall member 27 is scored at its inner and outer layers and folded so as to form a flap 110, the thickness of box beam 104 distant from its free end. End wall box beam 104 is then placed against the inner surface of the base 34 and web 28 of box beam 108 and flap 110 and inner wall 27 are tucked into position after adding the insulation 33. Preferably, the closing flap 50 of beam 108 is removed because, lacking a glass fibre and polyester layer, it is not protected. The web 28 of side wall box beam 108 is stapled to the outsidewall 34 of end wall beam 104. Here again, the staple is preferably of the type used in fast assembly of packing boxes in which the staple remains in the form of a U-shaped nail which pierces the insulating foam without disloding it. This line of staples can clearly be seen in FIG. 12 which although it illustrates another point also shows how the free edge 114 is held by staples 112 throughout its whole length. Clearly, insulation 35 was added to end wall beam 104 before that end wall beam has closed; insulation 33 and 35 being cut from a single piece 32 to avoid any cold spots.
The purpose of items 136, 138 which appear on this drawing will be understood more easily after a discussion of FIGS. 10, 11 and 12.
FIGI9 will be probably understood easily by its analogy, with FIG. 8. Roof box beams 101, 103 are normal but the last but one, 105, and the last, 107, are left open. Open box beam 105 receives end wall beams 104 (broken away) 106 (partsectioned) 109, 111, etc. The last roof box beam 107 of course forms a gableend overhang, and will be closed after the end wall and roof havebeen stapled together. As before the innerwall 27 of roof box beam 105 is scored to provide a fold at a distance corresponding to the thickness of a box beam from the free end. Roof box beam 105 accepts the outer faces of end wall box beams 104etc. against the insulation 32 of the roof box beam 105. This is desirable to avoid cold spots due discontinuity of insula-' tion although of course loading is taken, as before by staples 112 which fasten the web 28 of roof box beam 105, the web 34 of roof box beam 107 and the span 30 of the end wall box beam, 106, together. The flap 113 and inner wall 27 of roof box beam 105 are then tucked into position, and beam 107 is then closed.
FIG. 10 illustrates in detail the finishing of the roof and shows a supplementary construction to that of FIG. 6. Roof box beam 54 is shown cut away to illustrate a preferred embodiment; while it is entirely adequate for tropical countries to hang the whole weight of the roof (which is not heavy) by the series of flaps 84 shown on FIG. 6, preferably the half span box beam is given additional support for those countries in which snow loading may be a serious factor. Thus, wooden beams 116 and 118 are first stapled to roof box beams 54 by staples 120. This is done before the side wall and half roof subassembly, as shown in FIG. 5, is placed into the position shown in FIG. 6; hence, when the half roof span box beams 54 are fitted against the roof ridge members 82, supporting members 116 also fit against the lumber ridge members 82 and are secured to them either by nailing or any other convenient method.
Also shown in FIG. 10, for convenience, is one method of finishing the joints between the various box beams of which the roof is composed. It will readily be understood from FIGS. 4, 8 and 9 for instance, that the outside wall will have a cuspate cavity between two adjacent beams. This is enhanced by the thickness of the fibreglass layers 34 which cannot be made to butt against one another, and hence the paperboard beneath is exposed at the cusp between the outer wall and the web of the box shaped member. In order to cover this gap a tape of glass fibre and resin, 122, runs the length of this joint between two adjacent beams in order to seal the gap. Glass tape is well known and may be used, for example, even with an air drying plastic glue compatible with the resin of the glass fibre layers 30; however, it is preferable to use a percent reactive component type of adhesive such as vinyl acetate modified polyester.
Regardless of what method of closing the gaps has been used, after this operation a ridge cap 124 of glass fibre reinforced resin is placed over the joint at the top of the roof, to prevent precipitation and moisture from reaching the paperboard beams through the joints at the top of roof ridge members 82. Preferably this is fastened in place by an adhesive as described above.
FIG. 1 1 concerns a much prefered way of closing the gap between the box beams on the outside. A T-shaped section hereafter called a spline 126, of glass roving filled polyester resin is in the region of 0.015 to 0.025 inch thick in the cross member and twice the thickness in the stem or upright; the stem is about 1 16 inch deep and the cross member is about 3 inches wide.
These are painted on the contact surfaces with a compatible bonding agent such as a vinyl acetate modified polyester and fitted between the beams, with the stem 127 between adjacent glass polyester layers 28, 30. This fitting can be done after assembly of the building if the stapling is not close to the outer edge of the layers 28, 30 or alternatively the splines can be assembled at the stage shown in FIG. 4 or with the box beams. FIG. 8 shows a spline in position.
Whichever method is used, the purpose of these splines is to provide an unbroken glass fibre and resin channel round the outside of each paperboard beam.
The result of this is to prevent weakening of the paperboard at the corners. When the more easily applied glass tape is used an integral shell is formed but part of the strength of the whole structure depends upon the glass webs which is joined to the shell by paperboard. Temperature cycles and the change of relative humidity within the box beam can result in the paperboard working" and the joint losing strength. Consequently, the spline is a valuable addition to the integrity of the building.
Preferably, the glass spline is made from a formulation comprising 100 parts by weight of random fibre glass mat having a weig l1 t of l ounce persquare foot of the type designated as M750 in the Owens Corning Fibreglas (Fibreglas" is a registered trademark) 99 parts of a polyester resin such as that designated as 33-450 by Reichold Chemicals and 1 part of methyl ethyl ketone peroxide. The high glass content enables adequate tensile strength to be developed in the preferred thin sections. Of course, the glass does not have to be in the form of a mat and chopped strands having fibre length of 1 96 to 2 inches can be used in this preferred form.
However, it will be understood that other glass resin materials such as a standard industrial formulation made from 1 5% ounce per square foot glass mat with 4 k ounce of resin could also be used for making the spline although the higher materials content and thickness both make it less desirable, from the point of view of expense and outside finish.
The 100 percent reactive component type of adhesive formulation is also fairly simple and well within the ability of those skilled in the art. For example, a satisfactory formulation is IOO parts by weight of Reichold 33-450 resin, 2 parts by weight of Union Carbide Calidria R-G 244, 0.2 parts of ethyl glycol (obtainable from Dow Chemical for instance) and 150 parts of Silco-Sil No. 390 (a 300 mesh silica flour obtainable from Ottawa Silica). The flour inhibits sag or dripping without adding unduly to viscosity, and as this adhesive holds as well as the substrate it is unnecessary to use fibrous fillers to add strength.
The inside of the building can also use the same splines as the material is relatively inexpensive; alternatively, a paper based masking tape can be used to cover the cuspate joints between beams, because there is no problem relating to long term loss of strength problem. FIG. 11 also concerns the protection of the corner of the building where there will be a line of paperboard exposed between a box beam outside glass layer and a web glass layer. Corner piece 136 may be made separ ately in angle stock or may be cut from spline 126. Strip 138 is used to protect the vertical cut edge 114 of a comer beam.
The main purpose of FIG. 12 is to show the method used for closing the roof box beams 101, 103, 105, 107 at the end of the eaves. This is done by cutting away the webs 128 (corresponding to side wall 28 and 30 of two adjacent beams) locally and stapling a lumber board, 130, in position so as to close all the ends of the roof box beams at the eaves. Not only does this reduce labor time and cost but also it forms a convenient member which will take nails and screws. Thus, in some localities it may be necessary to add eavestrough to the building and this can be done most conveniently.
A second purpose of FIG. 12 is to show the closing of the slot openings 66 and 68 by a paperboard with a polyester impregnated glass fibre layer soffit board 132. This is necessary to ensure that soft paperboard is not exposed directly to the elements, and similarly a soffit board 134 is required to protect the underside of the last roof beam 107.
The integrity of the corners of this beam and the building are also shown on FIG. 12 where corner angles 136 illustrated on FIG. 8, are bonded over the glass discontinuity. The material of these angles is the same as that of the splines of FIG. 11. Furthermore, a sealing piece of the same material, 138 covers the exposed edge 1 14 of box beam 108 to prevent moisture entering the beam.
The whole building is then sprayed with a thixotropic paint for decorative effect; such a paint may advantageously be of a light color for tropical countries and will contain intumescent materials in an organic vehicle to assist fire proofing. The interior of the building is also treated with an intumescent material in solution which may be water soluble if desired, but particular care is required that the outside finish should cover all cut paperboard ends to prevent moisture entry by wicking action.
1. A weather-proof shelter having a load bearing member comprising, in combination:
a. a multitude of elongated similar paperboard beams, each beam having at least an outer surface portion and two web portions inwardly thereof to form a U-shaped channel, each of said portions having, on that face thereof which is directed away from the interior of the channel, a reinforcing coating of glass fibers in weather-resistant plastic adhered thereto, the three coatings together being adapted to cooperate to reinforce said three portions, the reinforcing coatings on the outside of the outer surface portions of the multitude of beams being substantially coplanar; and
b. a multitude of elongated T-section splines of glass fiber plastic, each spline having a stem and a cross member, the stem of each spline being betweenthe coatings on the web portions of two adjacent beams and being bonded thereto, and the cross member of each spline being in engagement with the coatings on the outer surface portions of said two beams and being bonded thereto, in consequence of which each spline completes the structural integrity of the juncture of the two adjacent beams between which the respective spline is located.
2. The weather-proof shelter as claimed in claim 1, wherein the plastic of the glass fiber reinforcing coatings and the plastic of the glass fiber reinforcing spline are both polyester resins and the bonding material is a vinyl acetate modified polyester resin.
3. The weather-proof shelter as claimed in claim 1, and further comprising:
c. an elongated angle section of glass reinforced plastic bonded to an end beam of the load bearing member at the outer surface portion and a web portion thereof to complete the integrity of an exposed corner of said end beam. 4. The weather-proof shelter as claimed in claim 3, wherein the angle section has the same dimensions as the stem and one half the cross member of one of said T-section splines.