METHOD FOR ASSEMBLING A WEATHER-PROTECTING ROOF TRUSS AND A WEATHER-PROTECTING ROOF TRUSS BUNDLE

Abstract

Disclosed is a method for the installation of a roof truss on an upper part of a building. A roof truss package includes multiple trusses spaced from each other to be mounted on top of upper runners on the building's opposite walls. The method includes using a prefabricated roof truss package in which the individual trusses are disposed side by side in a bundle, with weather protection present in a pleated condition on top of the bundle. The bundle is unfolded at construction site in such a way that the adjacent trusses become locked at a certain distance from each other by brace members included in the trusses and at the same time the weather protection unfolds to cover the trusses and the intervening space. Finally, the individual trusses are fastened to the upper runners. Also disclosed is a prefabricated roof truss package which is provided with a weather protection.

Claims

1. A method for the installation of a roof truss on an upper part of a building, said roof truss comprising a plurality of trusses (3) spaced from each other to be mounted on top of upper runners (6) present in an upper part of the building's opposite walls, said roof truss working as a roof sheathing, characterized in that the method comprises using a prefabricated roof truss package in which the individual trusses (3) are disposed side by side for a bundle (1) and previously provided with a weather protection (2) present in a pleated condition on top of the truss bundle; unfolding the bundle (1) at construction site in such a way that the adjacent trusses (3) become locked at a certain distance from each other by means of brace members (4, 5) included in the trusses and at the same time the weather protection (2) unfolds to cover the trusses and the intervening space, and finally fastening the individual trusses by outer edges thereof to the upper runners (6).

2. A method according to claim 1, characterized in that it comprises initially hoisting the bundle (1) onto the roof and propping it to an upright position at a desired installation point from which its unfolding along the upper runners (6) is commenced.

3. A method according to claim 1, characterized in that it comprises unfolding the bundle (1) previously and locking the trusses (3) at a certain distance from each other and then hoisting the same as a completed roof truss onto the roof and fastening the same to the upper runners (6).

4. A roof truss package, comprising a plurality of trusses (3) which are spaced from each other and adapted to be mounted on top of upper runners (6) present in an upper part of the opposite walls of a building, and said trusses work in such an installed condition as a roof sheathing, characterized in that the roof truss package is provided at a manufacturing plant with a weather protection (2) which is attached to the trusses (3), that the roof truss package has its trusses (3) arranged for a bundle (1) in which the weather protection (2) is in a pleated condition, and that the trusses (3) are provided with brace members (4, 5) capable of locking the adjacent trusses (3) at a certain distance from each other as the bundle is unfolded.

Description

[0028] The invention will now be described with reference to the accompanying drawings, in which:

[0029] FIG. 1 shows one roof truss package for use in a method of the invention at a commencement stage of installation,

[0030] FIG. 2 shows the roof truss package of FIG. 1 in a partially installed condition,

[0031] FIGS. 3a, 3b show one detail in a roof truss of the invention, and

[0032] FIG. 4 shows a roof truss of the invention in an isometric view.

[0033] In the process of installing a roof truss, it is a roof truss package in the form of a bundle which is lifted with a hoist onto the roof and placed at one gable of the house or at some other desired starting point and braced to an upright position from an outermost truss 3. In the exemplary case shown in FIG. 1, a bundle 1 has been hoisted to the upper part of a building onto top runners 6 of the building's opposite walls 7 at one gable of the building. The top runners are mounted to rest on load-bearing upright posts of the walls.

[0034] FIG. 1 shows also one exemplary embodiment of a roof gable element, which comprises an eaves section 12 and a gable wall section 13, said gable element having been preferably pre-fitted at the factory to the attachment with the roof truss at both ends thereof. Prefabrication in this context refers to manufacturing conducted in a factory building or the like sheltered space irrespective of whether the production is automated or mechanized or manually conducted production. The eaves section 12 comprises fascia boards 18 and soffit boards 19. The gable wall section 13 includes studwork 14, which is fastened to an outermost truss 3 of the bundle 1 and to which is fastened a wind protection slab 15. On top of the wind protection slab is mounted studwork 16 with exterior wall panels 17 fastened thereto.

[0035] After this, the bundle is unfolded by moving it with the assistance of an installation cradle (not shown) along the roof, the bundle releasing one truss at a time. FIG. 2 shows a bundle in a partially unfolded condition. The unfolding can be conducted e.g. by means of a winch or a hoist. Preferably, the installation is conducted from inside the building by using a remote controller for manipulating the winches which operate the installation cradle. The trusses are fitted with lower brace member 4 and upper brace members 5 capable of locking the trusses at a predetermined distance from each other to provide a previously supported structure, wherein individual trusses, except for the first truss, need not be separately supported on the building frame structures. The number of each of the brace members 4 and 5 is at least two per truss.

[0036] FIGS. 3a, 3b show one preferred embodiment of the lower brace members 4 more closely in schematic views of principle. FIG. 3a depicts a starting condition, and FIG. 3b shows a condition in which a truss 3′ next to the gable truss 3 has been removed from the gable truss to a distance defined by the brace member 4. In the presented exemplary embodiment, the brace member 4 consists of a two-component support, having first and second support arms 4a, 4b which are pivotally connected at one end thereof to the trusses 3 and 3′, respectively, and at the other end thereof to each other with an articulated joint 4c capable of locking the support arms to each other while defining a distance between the trusses 3, 3′. The upper brace members 5 are designed similarly as a two-component unit. The number of brace members 4 and 5 is typically 4-6 in each inter-truss space. The brace members are preferably accompanied by clamping elements which keep the truss bundle intact and, upon unclamping, release the brace members of the next inter-truss space to unfold as the truss bundle is advanced. The material for the brace members can be e.g. metal, plastics or wood or various combinations thereof.

[0037] After unfolding, the trusses are attached by outer edges thereof with fastening means to upper runners 6 for preventing the wind from jerking the truss bundle off from top of the upper runners. The fastening means may comprise e.g. an angle bar or the like. The roof truss bundle is previously equipped at the factory with a weather protection 2, which is in a pleated condition on top of the bundle 1 and in attachment with the trusses, such that, as the bundle is being unfolded, the weather protection straightens out to cover the space between adjacent trusses. Once the bundle has been completely unfolded, the roof is immediately in a weather protected condition. The weather protection can have two or more layers, thereby facilitating the use of new materials more advanced in terms of their absorption/breathability or insulating properties.

[0038] Alternatively, a roof truss of the invention can be previously unfolded even on the platform of a transport vehicle, on retractable rails or on the ground, and then hoisted onto the roof, whereby all that is necessary to do on the roof is to fasten the trusses to the upper runners.

[0039] FIG. 4 shows in a schematic isometric view a roof truss in a partially unfolded condition. The weather protection 2 is in this example fastened to individual trusses by means of ventilation ribs 11. The weather protection is provided separately on both slopes of the roof for enabling the pleating thereof for transport. On top of the ventilation ribs 11 at the roof apex will be provided a separate weather protection strip (not shown), which enables effective ventilation in a completed roof structure and protects a ventilation gap of the weather protection 2 developing at the apex. The strip can be previously mounted on top of the ventilation ribs 11 of the weather protection 2 on one of the slopes to facilitate its installation while the roof truss is in a completely unfolded condition.