FIELD OF THE INVENTION

THIS INVENTION relates to a modular building system.

BACKGROUND TO THE INVENTION

Home building falls into two distinct categories. The first is the "bricks and mortar" category where a strong structure is provided which will withstand most weather conditions. It has, as a major disadvantage, the cost of building in this way but this building technique also has the disadvantage that skilled labour is required.

The second category comprises conventional timber frame homes which are constructed in North America as well as places such as Northern Europe and Japan. Building in this way is also expensive and requires skilled labour but is not as expensive as the bricks and mortar method. Its disadvantage is that the resultant structure is vulnerable to high winds such as occur in the hurricanes and tornados that are frequently encountered in the United States.

The present invention provides a modular timber frame building system which, whilst having the advantage of rapid erection, also results in a lower building cost than conventional "on site" timber frame construction. This is because the modules can be constructed in a controlled, cost effective factory environment. The modular system additionally has the advantage of greater strength to enable a home built in accordance with the present invention better to withstand the high winds of hurricanes and tornados.

BRIEF DESCRIPTION OF THE INVENTION

According to one aspect of the present invention there is provided a modular building structure which comprises a pre-fabricated column and a prefabricated wall panel, components of the column and components of the panel overlapping one another and being secured together. Said column preferably comprises four vertical planks arranged on the four sides of a rectangle so that the column is hollow.

A vertical edge zone of a first plank of the column can protrude beyond the vertical edge of a second plank which is adjacent to it, a strip being secured to said edge zone of the first plank in the angle between it and the second plank and extending beyond the edge of the first plank, and said edge zone of the first plank and said strip constituting one of said components of the column.

It is also possible to secure a further strip to the outer face of the second plank adjacent the end thereof remote from the first plank, the further strip constituting another one of said components of the column and protruding from the outer face of the second plank by the same distance as the edge zone of the first plank protrudes beyond the second plank.

The edge of one of said planks can abut one face of a further plank and an intermediate strip can be secured to the other face of said further plank in alignment with said one plank, a further strip being secured to said intermediate strip and extending beyond said intermediate strip in the direction away from said further plank, said intermediate and further strips constituting one of said components of the column.

Said components of the building panel are preferably vertically extending protruding edge zones of the panel. In one form the panel includes a vertically extending beam comprising vertically extending flanges joined by a web, there being a strip secured to one of said flanges and extending horizontally beyond said one flange, said flanges and said strip constituting said components of said panel.

In the preferred form the panel comprises a horizontally extending beam at the upper end thereof, the beam being of l-shape and including two horizontally spaced flanges with a web extending between them, there being a strip inserted between said flanges and supported by said web, said flanges extending above said inserted strip to form an upwardly open cavity. Said cavity can communicate with the upper end of the hollow interior of the column, the cavity and the hollow interior having reinforcing rods therein and the cavity and the hollow interior being concrete filled to provide a reinforced post in the column which is integral with a reinforced beam in the cavity.

According to a further aspect of the present invention there is provided a building method which comprises prefabricating a hollow column, prefabricating a panel, presenting the panel to one side of the column so that vertically extending components of the panel overlap with vertically extending components of the column, and securing the overlapping components to one another.

The method can further comprise providing an upwardly open cavity along the top of the panel, placing reinforcing in the cavity and in the hollow column, and pouring concrete into the cavity and into the hollow column to form an integral vertical post and horizontal beam.

Preferably the panel spans between two columns and the ends of the beam are integral with posts cast into said columns.

According to another aspect of the present invention there is provided a ceiling panel which comprises a first sub-panel and a second sub-panel superposed on the first sub-panel and displaced both longitudinally and transversely with respect to the first sub-panel whereby all four edges of the ceiling panel are rabbeted.

Each sub-panel is preferably of hollow construction and comprises a frame and facing sheets secured to opposite sides of the frame.

According to a still further aspect of the present invention there is provided a floor panel comprising an upper deck and a lower deck with beams between the decks, each beam comprising an upper flange secured to the underside of the upper deck, a lower flange secured to the upper surface of the lower deck and a web between said flanges, the flanges of a beam along one edge of the panel protruding horizontally beyond the edges of the decks and edge zones of the decks along the opposed edge of the panel protruding beyond the flanges of a beam along said opposed edge of the panel. BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:

Figure 1 is a top plan view of the corner column of a modular building system in accordance with the present invention;

Figure 2 is a top plan view of a column located at an intermediate location in a wall; Figure 3 is a top plan view of a column provided where four walls meet; Figure 4 is a plan view of a column provided where three walls meet; Figure 5 is a side elevation of a wall panel;

Figure 6 is a top plan view, to an enlarged scale, of one end of the wall panel and also shows part of an adjacent column;

Figure 7 is a plan view of a ceiling panel;

Figure 8 is an edge view of the ceiling panel of Figure 7;

Figure 9 is a top plan view of part of a floor; and

Figure 10 is a section on the line X-X of Figure 9.

DETAILED DESCRIPTION OF THE DRAWINGS

The corner column 10 shown in Figure 1 comprises four vertical plywood

planks 12.1 , 12.2, 12.3 and 12.4 arranged in a box formation thereby to form the column which has a vertical height equal to that of the room to be constructed. A suitable height

is 2.4m. The plank 12.1 extends horizontally beyond the plank 12.2 (to the right as viewed in Figure 1 ). The planks 12.2 and 12.4 extend beyond the plank 12.3 (in the "downward" direction as illustrated). The planks 12.1 and 12.4 abut to form a neat corner.

A vertical strip 14 of timber or plywood is secured to that part of the plank

12.1 which projects beyond the plank 12.2 and the strip 14 itself protrudes beyond the plank 12.1 . This provides an interlock with a wall panel as will be described. A smaller strip 16 is connected to the plank 12.2 in alignment with the plank 12.3. A further vertical strip 14 is secured to that part of the plank 12.2 which protrudes beyond the plank 12.3.

The column of Figure 2 differs from that of Figure 1 in that the planks 12.1 ,

12.2, 12.3 and 12.4 are somewhat differently arranged. Specifically the plank 12.1 extends beyond both planks 12.2 and 12.4 and the plank 12.3 spans between planks

12.2 and 12.4. Strips 14 and strips 16 provide interlocking formations of the same construction as described above in relation to Figure 1 .

The construction of Figure 3 permits four wall panels to be interlocked with the column constituted by the planks 12.1 , 12.2, 12.3 and 12.4. The various components in Figure 3 have been designated by the same reference numerals as used in Figure 1 .

The construction of Figure 4 provides a junction between two aligned wall panels and one at right angles to the two aligned wall panels.

Simply by way of example if the panels are what are referred to as "8x4" panels (meaning 8 feet high by 4 feet wide in Imperial measurements) the strip 14 can be 50mm long and the strip 16 can be 25mm long. In metric measurements "8x4" in feet is equivalent to 2440mm x 1220mm. To provide for flexibility in the design of structures a second panel size of 2440mm x 610mm can be provided. The wall panel 18 shown in Figure 5 is rectangular in shape and consists of four beams 20. The beams 20 are shown as being of the form described in the specification of South African patent no. 90/10317. Each beam comprises two elongate parallel wooden flanges 22 (see particularly Figure 6) joined to one another by a web which is in the form of a metal strip 24 which is bent to a zig zag form. Each bend 26 of the strip 24 is nailed or otherwise secured to one of the flanges. In Figure 5 the metal strips 24 are hidden behind the front flanges

22. However, it is also possible to use I-beams comprising two wooden flanges and a wooden web.

Corner gussets 28 prevent the beams 20 moving with respect to one another.

In Figure 6 one of the beams, the left hand one as viewed in that Figure, is designated 20.1 and extends vertically. Its flanges are designated 22.1 and its metal strip is designed 24.1 . The other beam shown in Figure 6 is designated 20.2 and has horizontally extending flanges 22.2 and a horizontally extending strip 24.2. The left hand end surfaces of the flanges 22.2 of the beam 20.2 about the vertical faces of the vertical beam 22.2.

As shown in Figure 6, a strip 30, identical to the strip 14, is secured to one of the vertical flanges 22.1 and extends horizontally beyond the vertical edges of both flanges 22.1 .

Weather boards 32, 34 are secured to the outer faces of the planks 12.1 , 12.4 in Figure 1 . Likewise a decorative weather board 36 is secured to the outer face of the plank 12.1 in Figure 2. The fact that the column of Figure 3 abuts walls on all four sides means that there are no exposed faces and no weather boards are fitted to the column. The column of Figure 4 has one exposed face and a weather board 38 is secured to this face.

A corner column is shown in dashed lines in Figure 6 and the components of this column have been designated using the reference numerals of Figure 1 . When the panel is presented to the column, the strip 30 overlaps with the plank 12.1 and the strip 14 overlaps with the flange 22.1 . Nails or other fasteners are driven through to secure the strip 30 to the plank 12.1 and the strip 14 to the flange 22.1 .

The beams 20 are covered on both sides by sheets, designated 40 and 42 in Figures 5 and 6, which are secured to the flanges 22.1 , 22.2 of the four beams 20 which constitute the frame. Only a small centre part of the sheet 42 is for illustrative purposes shown in Figure 5, the remainder being omitted so that the beams 20 are not concealed by it.

The weather board 32 is shown in Figure 6. Between the board 32 and the sheet 40 there is a vertically extending filler strip 44. This conceals the fasteners which are used to secure the flange 22.1 to the strip 14 of the column. Similarly there is a filler strip 46 between the sheet 42 and the column.

A further column of any one of the forms illustrated in Figures 1 to 4 is placed against the other vertical edge of the panel illustrated in Figure 6.

A ring beam can be cast to impart strength to the structure to enable it to resist the high winds that develop during storms. To provide such a ring beam each column of the completed wall and column structure has an array of reinforcing rods placed in it. A horizontal strip of, for example, plywood is inserted into the top of the wall panel and pressed down so that it is supported by the element 24.2. The flanges 22.2 extend to positions above the level of the inserted strip to form an upwardly open cavity. The line E in Figure 6 indicates the position occupied by the left hand edge of the inserted strip. Reference letter O indicates an opening between the edge E and the plank 12.2 of the column. This opening is plugged using a block of a material such as foamed plastic.

The upper edge of the plank 12.2 in this form is below the level of the upper edges of the planks 12.1 and 12.3. Consequently the upwardly open cavity defined by the strip resting on the element 24.2 and the upper parts of the horizontally extending flanges 22.2 of the beam 20.2 continues over the upper edge of the plank 12.2 and into communication with the upper end of the hollow interior of the column. Horizontal reinforcing wires in the cavity above the inserted strip, and extending between adjacent columns, are tied to the vertical reinforcing wires in the columns on each side of the panel 18.

Concrete poured into the voids of the two columns and into the horizontal cavity forms an arch which comprises two reinforced vertical posts in the columns and a reinforced horizontal beam in the cavity. The posts and beam are integral with one another.

When a column of the form shown in Figure 2 is used, the planks 12.2 and 12.4 must be shorter than the planks 12.1 and 12.3 to allow the upwardly open cavities of the wall panels on each side of the column to communicate with the void in the hollow column. The planks of the column of Figure 3 all terminate at the same level which is at about that of the inserted strip forming the bottom of the upwardly open cavities of the wall panels.

The plank 12.4 in Figure 4 terminates at a level above the other planks 12.1 , 12.2 and 12.3.

Consequently whilst the structure illustrated is a timber frame construction, it can be strengthened by the incorporation into it of the post and beam structure described.

By extending the cast concrete posts of the column upwardly, it is possible to construct a multi-storey building.

Turning now to Figures 7 and 8, the ceiling panel 48 illustrated comprises two sub- panels 50, 52 which are secured to one another in the offset position illustrated so that two edges of each sub-panel protrude beyond the corresponding two edges of the other sub-panel. This provides a rebate along all four edges of the panel 48 so that two other panels be interlocked with the panel 48. Two other panels interlocked with the panel 48 are shown in dotted lines at 48.1 and 38.2 in Figure 8.

The panels 48, 48.1 and 48.2 are all secured to the underside the horizontal members of roof trusses the ends of which are supported by the columns and wall panels forming the walls of the building. The space within the panel 18 can contain heat insulating material such as a wool or a foamed plastic insert. The weather boards can be of compressed magnesium oxide.

Turning now to Figures 9 and 10, these illustrate the construction of the floor of a building as described above.

The floor comprises panels 54 which are placed on a concrete slab or any other suitably levelled sub-structure. Each panel 54 comprises a top deck 56 and a bottom deck 58 of plywood with beams 20 of either of the forms described above between them. The components of the beams have been referenced using the same references as are used above.

As will be seen from Figure 10, the flange 22 of the beam along the left hand edge of the centre panel 54.1 protrudes beyond the decks 56 and 58. The flange 22 of the beam along the right hand edge of the panel 54.1 is set back from the edges of the decks 56 and 58. When panels 54.2, 54.3 of identical form and shown in dotted lines are placed on each side of the panel 54.1 , the decks 56, 58 overlap with the flanges 22.

The upper decks of each panel can be secured by screws or nails to the upper flanges of the beams of adjacent panels.

Two columns 10 are also illustrated in Figure 9. Between the columns there is a floor beam 60 comprising upper and lower flanges and a web between the flanges. The beam can be of either of the forms described above. The beam 60 has a width equal to that of the wall (not shown) which spans between the columns 10.

If desired the hollow interiors of the columns can be extended downwardly by holes dug in the ground below the floor.