GB2141762A

GB2141762A - Gable roof modules

Info

Publication number: GB2141762A
Application number: GB08414164A
Authority: GB
Inventors: Tore Johansen
Original assignee: Fjeldhammer Brug AS
Current assignee: Fjeldhammer Brug AS
Priority date: 1983-06-06
Filing date: 1984-06-04
Publication date: 1985-01-03
Also published as: DK273484D0; DE3421107A1; GB2141762B; SE8303185D0; FI842247A0; NO842132L; DK273484A; FI842247A; GB8414164D0

Abstract

A modular gable roof construction consists of a plurality of sections each comprising at least three parallel rafters (1) to which a roofing plate (2) of rigid material, for example plywood or fiberboard, is attached, such that each section has the nature of a rigid plate. Each of the sections on one side of the roof is hinged to the adjoining, corresponding section on the other side of the roof by hinges on the underside of the respective rafters (1,3) at the apex of the roof. The ends of at least the two outer pairs of rafters (1,3) on each section are joined to a tie beam (7). <IMAGE>

Description

SPECIFICATION Gable roof modules The present invention relates to a gable (saddle) roof construction, and in particularto gable roof modules comprising at least two roof trusses and a roofing plate, as well as to a method of erecting such roof modules at the construction site.

The most practical roof structure for climates in which snow can be expected to subject the roof to loading is the pitched gable roof or saddle roof, and it is thus the most common type of roof for housing construction. The supporting structure normally comprises a roof truss, i.e., two rafters disposed at an acute angle to form the roof peak and a tie beam connecting the lower ends of the two rafters and constituting the tension member in the construction.

The roof trusses thus in effect constitute a rigid beam, and the ends of the truss are placed on top of the ground beam of the house walls. In the past, roof trusses were cut and assembled at the construction site, but today they are usually produced at a factory and transported as a unit to the building site. The roof trusses are such large and heavy structures that manual transportation and erection of the trusses is cumbersome and labor-intensive. It is heavy, difficult work for two men to lift the trusses to the top of the wall and set them in place. Once the roof trusses have been positioned, a roofing plate must be attached to the rafters and some form of roofing material or tile is installed on the plate. Altogether, many different operations are required to transport the members to the construction site and to erect and assemble the roof.In addition, the roof work is performed relatively high off the ground, entailing a greater risk of accidents. In the autumn and winter this work may also be wet and uncomfortable, resulting in reduced efficiency.

Another drawback with prefabricated roof trusses is that, owing to their great length and the relatively small dimensions of the lumber, the truss usually has to be stiffened between the rafters and the tie beam by struts.

One then obtains a more rigid unit to transport, but in the finished building the diagonal struts will greatly reduce the usable floor space in the attic.

In the case of gable roof structures having a relatively acute roof pitch, prefabricated roof trusses cannot be used because their dimensions are too large to permit transportation on ordinary roads. For prefabricated housing having this type of steeply pitched roof, the roof trusses are generally made in two sections, which entails extra assembly work at the building site. Steeply pitched roofs have become popular because one then obtains so much head room that a portion of the attic floor space can be utilized as living space. Even larger rooms can be obtained by building dormers or bay windows in the roof.

The object of the present invention is to provide gable roof modules which can be produced and erected in a very simple manner, avoiding the above-mentioned drawbacks and providing a num ber of advantages.

This is obtained in accordance with the invention with a gable roof construction characterized by consisting of a plurality of sections each comprising at least three parallel rafters with an attached roofing plate of rigid material, e.g. plywood or fiberboard sheets, such that each section has the nature of a rigid plate, wherein the rafters of each section on one side of the roof are hinged to the rafters of each section on the other side of the roof on the underside of the rafters at the apex of the roof, where the upper ends of the respective rafters meet and coincide, and wherein the opposite, lower ends of at least the two outer pairs of rafters on each such module are joined to a tie beam.

A further development of the invention is characterized in that the ends of the tie beam are articulatedly connected to a pair of rafters, that the tie beam is divided between the ends thereof into sections which are shorter than the length of the rafters, and that the tie beam is spliced together with an easily attachable splicing means.

An actual embodiment of the invention is characterized in that the rafters are hinged at the apex of the roof by means of a plurality of hinges having a common hinge pin which extends transversely of the roof sections on the underside of the coincident upper ends of the rafters, and that the hinge pin is accessible through openings in the roofing plate.

A method of erecting the gable roof modules of the invention wherein the roof is in a collapsed state in which the tie beams have been pivoted to lie alongside the rafters, and the rafters have been folded together such that their inside surfaces are contiguous, and wherein one or more roof modules are disposed with the free ends of the rafters facing toward the rear of the truck bed of a truck or other suitable vehicle on which the modules are placed, is characterized in that a strap in the form of a double crow foot is fastened to the upwardly facing section of the roof module, two straps that form one-half of the double crow foot being fastened to the apex of the rafters, one strap on each side of a vertical plane at the middle of the section, and the two straps on the other half of the crow foot being fastened to each side of the section intermediate the ends of the rafters, that a crane hook is attached to the junction of the crow-foot straps, that the roof module is lifted as the outer end of the downwardly facing roof section is retained on the truck bed, that the hook is moved toward the rear of the truck bed at the same time that it is hoisted, that the tie beam members are pivoted into alignment and spliced together, and that thereafter the two strap members fastened intermediate the ends of the rafters are detached and the now-erected roof module is set in place on the walls of the house.

The invention will be described in further detail in the following with reference to the accompanying drawings, which show an embodiment of a gable roof module according to the invention and also illustrate the method of erecting the roof module.

Figure 1 shows a roof module in vertical section, Figure2 schematically illustrates how a roof module is connected to its neighboring modules, Figure 3 shows a portion of the apex juncture of the rafters, Figure 4 shows a first step in erecting the roof module, and Figure 5 shows a second step in erecting a roof module.

A roof section according to the invention consists of a plurality of rafters 1 which are connected to form a rigid plate by means of a roofing plate 2 of rigid sheet material, for example plywood or fiberboard, which is fastened to the top surface of the rafters.

This section is articulated to a second, identical section consisting of a plurality of rafters 3 similarly joined to a roofing plate 4. These two sections, which form two adjoining sides of the finished roof module, are hinged together 5 by means of a hinge 6. The ends 8 and 9 of a tie beam 7 are articulated to the rafters, and the tie beam 7 is divided at the center 10, where the two sections of the beam are spliced together by means of a fishplate or sleeve 11.

Diagonal struts are indicated by broken lines 10 and 12. To collapse the module, the joint at the middle of the tie beam is released and the two sections of the beam are collapsed toward the rafters to lie adjacent to the rafters. Thereafter the two side sections consisting of rafters and roofing plate are pivoted together such that their inside surfaces are adjacent.

In the illustrated embodiment the tie beam is divided into two sections, hinged to the rafters, and spliced together at the building site, but the tie beam could alternately be joined to the rafter sections at the construction site in the conventional manner.

Figure 2 shows how a section 13 is joined to its neighboring sections 13' and 13" on the same side of the roof. In this case each of the sections has three rafters wherin the outer rafters 1' and 1" are only half the thickness of the middle rafter 1. These are nailed or fastened in some other suitable manner to the corresponding rafters on the neighboring sections 13' and 13".

Figures 4 and 5 show how the roof modules of the invention are erected at the construction site. Figure 4 shows how a collapsed roof module is placed on a truck bed with the free ends of the rafters facing toward the rear of the truck bed. For the sake of simplicity only one roof module is shown, but it should be understood that several roof modules, enough for an entire house, can be stacked on top of each other on the truck bed. The roof modules are erected at the same time as they are unloaded from the truck. This is done with the aid of a strap 14 which consists of four parts, forming two pairs of crow feet 15 and 16. The two straps of the forward crow foot 16 are fastened to the juncture of the rafters at the apex of the roof, which faces toward the front of the truck.The two straps of the other crow foot 15 are fastened intermediate the ends of the rafters on the upwardly facing section of the roof module. The hook on a crane (not shown), which may be a crane mounted on the truck, a mobile crane or a construction crane, is fastened to the juncture of the four straps 14. The hook is simultaneously hoisted and moved toward the rear of the truck while the back end of the downwardly facing section of the module is held down, being attached to the truck bed orto the underlying module. Therefore, the upwardly facing section of the module will pivot relative to the downwardly facing section and the module will assume the erected position shown in Figure 5. With the two roof sections in this position, the sections of the tie beam 7 are pivoted down until they are in alignment and the tie beam is spliced together.By means of the sleeve or fishplate 11, the length of the tie beam can be varied within certain limits for adjusting the angle of pitch of the rafters 1, 3. After the tie beam 7 has been spliced, the crow foot straps 15 are detached and the two roof sections are hoisted into place on the house by means of the crow foot straps 16 which are attached to the apex of the roof module.

As mentioned above, the two straps of the front crow foot 16 shall be attached to the apex of the rafters. If these straps are attached to the two outer edges of the roof section, problems will arise when a new module is to be joined to the module already in place on the building because the hook of one strap will be in the way. In the embodiment shown in Figure 5, each module is provided with several hinges 6, preferably one on each pair of rafters, and these hinges are provided with a common hinge pin 17. Two openings 18, symmetrical about a central, vertical plane X, are provided in the roofing plates 2 and 4, so that the hooks on the straps of the crow foot 21 can be attached to the pin 24.

The roof section can be made even more complete by providing transverse members, for example beams 19, laths or strips, between the tie beams.

Insulation material 20, for example mineral wool mats, can be placed on top of these.

The construction of the roof modules according to the invention provides a number of advantages. The gable roof modules can be constructed under favorable, protected conditions inside a factory, saving both time and materials. Transportation is very much simpler since the various materials that go to form the roof modules are transported as a single unit. The roof modules can be set in place using simple crane equipment, so that the entire roof can be erected and assembled in only a few hours. The finished roof is watertight, at least so much so that there is no immediate pressure to complete the finishing work, for example nailing on strip boards for roof tiles, laying the tiles, etc. The roofers can thus avoid having to do this work in bad weather, when the work goes more slowly and the risk of accidents increases. Because the roof is erected quickly, the building will be exposed to moisture for a minimum period of time. Employing the method of the invention, erection of the roof sections may be performed very simply and rapidly.

Another important advantage obtained with the invention is that the gable roof sections, from a structional point of view, can be considered rigid plates. Therefore, if a stairway is to be guided through the beam layer, it is sufficient merely to join the two outer pairs of rafters by means of tie beams and the roof will still have adequate supporting strength . If openings are to be made in the roof surface for bay windows, dormers, skylights, etc., it is no problem to cut an opening up to 2.4 meters wide because of the strength and rigidity of the structure obtained through the plate effect.

Also, owing to the plate-like structure, half of the load on each roof section is transmitted to the corners. One can thus utilize materials of smaller dimensions on underlying openings, for example window openings.

Claims

1. A modular gable roof construction, characterized in that the structure consists of a plurality of sections forming the two sides of the roof, each section comprising at least there parallel rafters (1) to which a roofing plate (2) of rigid material, e.g.

plywood or fiberboard, is attached, such that each section has the nature of a rigid plate, thea th rafters of each section on one side of the roof are hinged to the rafters of the corresponding section on the other side of the roof on the underside of the rafters (1, 3) at the apex (5) of the roof, where the upper ends of the rafters (1,3) meet and coincide, and that the opposite, lower ends of at least the two outer pairs of rafters on each such module are joined to a tie beam.

2. A modular gable roof construction according to claim 1, characterized in that the ends of the tie beam (7) are articulatedly connected to the respective rafters (1, 3), that the tie beam (7) is divided between the ends thereof into sections each of which is shorter than the length of the rafters (1,3), and that the two sections of the tie beam (7) are spliced with an easily attachable splicing means (11).

3. A modular gable roof construction according to claim 1, characterized in that the rafters are hinged at the apex by means of a plurality of hinges having a common hinge pin (24) extending transversely of the roof section on the underside of the coincident upper ends of the rafters, and that the hinge pin is accessible through openings in the roofing plate (2).

4. A method of erecting gable roof modules according to one or more of the preceding claims at the construction site, wherein the roof has been collapsed with the tie beams pivoted to lie alongside the rafters which in turn have been pivoted together such that their inside surfaces are contiguous, and wherein one or more roof modules are disposed on the truck bed of a truck with the free ends of the rafters facing toward the rear of the vehicle, characterized in that a strap (19) in the form of a double crow foot is attached to the upwardly facing section of the roof module, the two straps that form one-half of the double crow foot (21) being fastened to the apex of the rafters, one strap on each side of a vertical plane (X) at the middle of a roof section, that the two straps on the other half of the crow foot are fastened to each side of the upper section intermediate the ends of the rafters, that a crane hook for a crane is fastened to the juncture of the crow-foot straps, that the roof module is lifted as the outer end of the downwardly facing section of the roof module is retained on the truck bed, that the hook is moved toward the rear of the truck bed while simultaneously being hoisted, that the tie beams are pivoted down into alignment and spliced together when the rafters have assumed the correct angle of pitch, and that thereafter the two crow foot straps that are fastened intermediate the ends of the rafters are detached and the now-erected roof module is set in place on the house with the aid of the crow foot strap (21).

5. A modular gable roof construction substantially as herein described with reference to and as illustrated in the accompanying drawings.

6. A method of erecting gable roof modules substantially as herein described with reference to and as illustrated in the accompanying drawings.