The invention relates to a method of constructing a roof for a building, for example in new or repair construction of buildings, as well as to a roof constructed with such a method. Constructing a building roof is typically one of the most essential building construction phases, since thereby is provided i.a. weather protection for building interiors. Accordingly, it functions in the building process as one essential stage of construction in view of which the other building process phases must be correctly scheduled. The construction of a building roof and roof structure, for example when building single-family and row houses, may typically take several days. During this period, the previously erected wall structures, on top of which the roof to be constructed is resting, will be exposed to weather and possible water damage, as well as to mold problems subsequently caused thereby. Patent application Fl 20145950 discloses one solution for rapidly providing a weather protection, comprising roof trusses for a roof structure, and a weather protection integrated therewith. In this solution, the prefabricated roof trusses for a roof structure, along with the weather protection, are assembled at a factory for a roof truss package in which the individual roof trusses are disposed side by side in a bundle and the weather protection is attached in a pleated condition on top of the truss bundle. At construction site, the truss bundle is lifted onto the upper runners of wall structures and unfolded in such a way that the adjacent trusses become locked at a certain distance from each other by means of 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 of wall structures. Thereby is provided, typically in a couple of hours, a roof structure bracing assembly along with weather protection for a building, upon which bracing structure can then be constructed the rest of the roof structure in a typical fashion. By this solution is also provided a capability of ensuring a correct and precise placement of roof trusses in locations designated therefor.

The construction of a roof surface-comprising structure on top of roof trusses nevertheless continues to be a time consuming process, which is further hindered by occupational safety regulations and hazards due to work at height. The present invention provides a rapid method of constructing a roof on top of the load-bearing roof trusses of a roof structure, whereby the time spent for working on the roof, as well as workplace safety problems related thereto, can be effectively minimized. In addition, the expedited roof manufacturing process can be utilized in speeding up the overall house building process.

In the solution of the invention, the roof is constructed from prefabricated roof panels, which are to be lifted onto roof trusses and comprise a roof surface, and which are fastened to the roof trusses with locking members, thus enabling a rapid final secure fastening of the roof panels in place. Thereby is provided a capability of assembling a roof surface structure at construction site in a few hours as opposed to the conventional building of a roof over several days. Further, in the solution of the invention, a capability is provided of tailoring the prefabricated panels to comply with intended applications, as well as of outfitting the same as necessary, for example with solar panels, whereby stages of work to be performed on the roof can be minimized.

The method of the invention for building a roof comprises constructing first for an upper part of the building a load-bearing support structure for the roof from roof trusses, on top of said support structure being constructed a roof structure comprising a roof surface, the roof structure comprising a plurality of prefabricated roof panels, said roof panels being hoisted onto the top of roof trusses included in the support structure provided in the upper part of the building and being fastened to the roof trusses, and fastening the roof panels to the roof trusses there is performed by using at least one locking piece, by displacing said locking piece with respect to a roof truss and/or a roof panel present on top of said roof truss in a plane substantially parallel to a junction surface of the roof truss and/or the roof panel, or by displacing a roof panel with respect to the locking piece in a direction defined by the locking piece's longitudinal center axis, there is achieved a final attachment and locking of the roof panel in place with respect to the roof truss.

The definition "roof truss" refers in this context to a framework or roof truss of lat- tice type design, which constitutes a roof structure bearing the load from top of the building's walls.

In one preferred embodiment for a method of the invention, the locking piece is a substantially plate-like object provided with asymmetric slots, the locking between a roof truss and a roof panel being achieved by way of said asymmetric slots. Al- ternatively, the locking piece can be for example a gutter, which is present in a roof truss mounting rail or in a panel fastening member, and which attaches to a counterpart's matching locking formation as the panel is moved. The locking piece may also be for example a locking pin or protrusion, which is present in a truss or in a roof panel fastening surface, and which finds its way and locks to a counter- part's locking formation as the roof panel is lowered directly in place.

In one preferred embodiment for a method of the invention, the locking piece is a protrusion type object, which is fixed to a top surface of the roof truss directly or by way of an adapter, and the roof panel locking to said locking piece in a form closed manner by lowering the roof panel on top of the roof truss and the locking piece. In this embodiment, the locking piece can be for example a pin type protrusion whose base portion is formed with a narrowing for establishing a form closed locking.

In one preferred embodiment for a method of the invention, the load bearing support structure for a roof is assembled by lifting a prefabricated roof truss bundle on top of the upper runners of a building's wall structures, the roof truss bundle is unfolded by pulling on a truss included in the bundle, whereby the bundle's roof trusses are locked by way of brace elements included in the bundle at a predetermined distance relative to each other, and with the bundle completely unfolded and the roof trusses located at final positions thereof, the roof trusses will be fas- tened to the upper runners of a building's wall structures. This enables the benefits of a rapid roof truss structure assembling method known from patent publication Fl 20145950 and a rapid roof panel and their fastening solution of the invention to be preferably combined, hence further enhancing and expediting the construction of a roof for a building. In one preferred embodiment for a method of the invention, the roof panel is formed with at least one block or section, which attaches to the roof truss and by way of which the fastening of a roof panel to a roof truss is implemented. Such a section can be for example a rail type adapter included in the roof panel or a recess formed in the roof panel wherein settles the top surface area of a roof truss. In one preferred embodiment for a method of the invention, the roof panel is made up of a frame or framework and a part or section constituting the roof surface. The roof panel can also be designed for example as box-type structure.

In one preferred embodiment for a method of the invention, the roof panels are not load-bearing members of the roof structure in the direction of trusses. However, the roof panels must have a required load bearing capacity in the intervening area between roof trusses.

In one preferred embodiment for a method of the invention, the building's roof is a pitched roof, a mono-pitch roof, a hip roof, a mansard roof or a broken-pitch roof. The invention relates also to a roof and a roof structure built with the method.

More specifically, the method of the invention has its features presented in claim 1 . The dependent claims disclose preferred features and embodiments for a solution of the invention.

The invention will now be described more precisely by way of example with refer- ence to the accompanying figures, in which

Figs. 1 A and 1 B show schematically a first embodiment for a fastening solution of the invention,

Figs. 2A and 2B show schematically a second embodiment for a fastening solution of the invention, and Fig. 3 shows schematically a third embodiment for a fastening solution of the invention.

In figs. 1 A and 1 B there is shown schematically one fastening solution of the invention for fastening a roof panel 1 comprising a roof surface to a support structure of roof trusses 2 by using a joint rail 3, a joint enclosure 4 and a locking plate 5. Fig. 1 A shows the fastening solution in cross-section and fig.1 B shows the fastening solution in longitudinal section from a site of the joint enclosure 4 in an overhead view.

In the fastening solution shown in figs. 1 A and 1 B, there is first fastened the joint rail 3 provided with protrusions 7 to a top surface of the roof truss 2, for example with adhesive, screws or nails. The joint rail 3 is preferably shaped so as to fit in lateral direction tightly around a top surface and edges of the roof truss 2, as can be seen from fig. 1 A, to be able to determine an exact position of the protrusions 7 on the top surface of the roof truss 2. The joint rail 3 is preferably constructed from an appropriate metal and the protrusions 7 are fixed thereto for example by weld- ing, threaded connections or screw connections. The protrusions 7 can be made for example of metal or some appropriate plastic or composite material. To a bottom surface of the roof panel 1 is fastened a joint enclosure 4 settling and to be placed at the roof truss 2 and opposite to the joint rail 3. The joint enclosure 4 has its bottom surface formed with slots for the protrusions 7. The diameter and shape of the joint enclosure's 4 slots comply substantially with the diameter and shape of the protrusions' 7 base with the addition of a suitable clearance. The joint enclosure 4 is preferably constructed from metal and it can be fastened to the bottom surface of the roof panel 1 for example by welding in case the roof panel's bottom surface is of metal, with adhesive, screw fastening or rivets.

Inside the joint enclosure 4, against a bottom surface of its interior, is disposed a locking plate 5. The locking plate 5 can be manufactured for example from a suitable metal, plastic or composite material, and its width matches substantially an interior width of the joint enclosure 4, yet so as to enable easy displacement of the locking plate 5 within the joint enclosure in its lengthwise direction. The locking plate 5 is formed with slots 8 for the protrusions 7 of the joint rail 3, said slots being in a longitudinal direction of the locking plate 5 sufficiently extensive at one edge thereof to allow the protrusion 7 to pass through, and said slots narrowing towards an opposite edge of the slot as seen from fig. 1 B. Thus, with the joint enclosure 4 placed against the joint rail 3 and the joint rail's protrusions 7 extending into the joint enclosure's interior, the locking plate 5 will settle within the range of narrow- ings formed on the protrusions 7, whereby, when the locking plate 5 is displaced relative to the joint enclosure in its lengthwise direction, the narrowing section of the slots 8 settles within the range of narrowings of the protrusions 7 in a form closed manner so as to secure the roof panel 1 in its place with respect to the roof truss 2 as depicted in fig. 1 A. In figs. 2A and 2B there is shown schematically one second fastening solution of the invention for fastening a roof panel 1 to a to a support structure of roof trusses 2 by using a joint rail 13 and a check rail 14. Fig. 2A shows the fastening solution in cross-section and fig.2B shows the fastening solution in longitudinal section in a side view. In the fastening solution illustrated in figs. 2A and 2B, the joint rail 13 equipped with rungs 17 is first fastened to a top surface of the roof truss 2 for example with adhesive, screws or nails. The joint rail 13 preferably designed as an H-shaped profile, such that a mutual breadth between the inner surfaces of its side flanges matches substantially the width of the roof truss 2 as seen from fig. 2A in order to place the joint rail 13 in a lateral direction tightly around the top surface and the edges of the roof truss 2. The joint rail 13 is preferably constructed from an appropriate metal.

To a bottom surface of the roof panel 1 is fastened a check rail 14 settling at and in alignment with the roof truss 2. As seen from fig. 2A, the check rail 14 makes substantially a U-shape fastened by way of its solid web to a bottom surface of the roof panel 1 . The check rail 14 has a width matching substantially that of the roof truss 2 in order to fit, in the illustrated embodiment, between the side flanges of the joint rail 13 with a suitable clearance so as to enable a movement of the check rail 14 between the side flanges of the joint rail 13 in a lengthwise direction thereof with relative ease. The check rail 14 is preferably constructed from metal and it can be fastened to the bottom surface of the roof panel 1 for example by welding in case the roof panel has its bottom surface of metal, with adhesive, screw fastening or rivets.

To internal surfaces of the joint rail's 13 side flanges and to extend between the same are attached rungs 17 within a section above the joint rail's central web, i.e. opposite to the roof truss 2. For these rungs 17, the check rail 14 is formed with grooves 18 as depicted in fig. 2B. These grooves 18 consist of two segments within edge flanges of the check rail 14, of which segments the first groove segment extends in the plane of the check rail's side surface perpendicularly with respect to the check rail's longitudinal direction and the second groove segment extends from the end of the first groove segment in the plane of the check rail's side surface lengthwise of the check rail as depicted in fig. 2B. The first groove segment of the groove 18 has a width which is substantially greater than the diameter of the rung 17, for example 2 or 3 times the diameter of the rung 17, and the second groove segment of the groove 18 has a width which substantially matches the diameter of the rung 17 with a suitable added clearance.

A fastening according to the embodiment depicted in figs. 2A and 2B is achieved by hoisting a roof panel 1 equipped with a check rail 14 onto the top of a joint rail 13 resting upon a roof truss 2 in such a way that each of the check rail profile's flanges settles between the joint rail's side flanges and the first groove segments of a groove 18 settle at the rungs 17. This is followed by lowering the roof panel 1 , whereby the outermost ends of the check rail's 14 flanges settle against the surface of the joint rail's 13 central web. Finally, the roof panel is displaced jointly with the check rail relative to the joint rail 14 in a lengthwise direction of these rails, the rungs 17 proceeding to the ends of the groove's 18 second groove segment and the attachment between joint rail and check rail being established as depicted in fig. 2B.

In fig. 3 is shown schematically one third embodiment for a fastening solution of the invention for securing a roof panel 1 to a support structure of roof trusses 2 by way of a joint rail 23 and a joint enclosure 14. Fig. 3 shows the fastening solution in cross-section.

In the fastening solution depicted in fig. 3, the joint rail 23 equipped with protrusions 27 is first attached to a top surface of the roof truss 2 for example with adhesive, screws or nails. The joint rail 23 has its width matching substantially that of the roof truss 2, whereby its attachment to the top surface of a roof truss is easy and an exact position of the protrusions 27 on the top surface of the roof truss 2 can be determined. The joint rail 23 is preferably constructed from a suitable metal and the protrusions 27 are fastened thereto for example by welding, with threaded connections or screw joints. The protrusions 27 can be made for example of metal or a suitable plastic or composite material.

To a bottom surface of the roof panel 1 is fastened a joint enclosure 24 settling and to be placed at the roof truss 2 and opposite to the joint rail 23. The joint enclosure 24 has its bottom surface formed with slots for the protrusions 27. The joint enclosure 24 has the diameter and shape of its slots matching substantially a nar- rowing formed at a lower part of the protrusions 27, and said slots of the joint enclosure are designed at the edges thereof to as to allow by yielding or by an otherwise effected reversible deformation the penetration of a wider tip portion of the protrusions 27. Once the wider tip portion of the protrusions 27 has passed through a slot of the joint enclosure, the slot's edges resume an original position thereof, hence locking the joint enclosure 24 and the joint rail 23 to each other as depicted in fig. 3. The joint enclosure 24 is preferably constructed from metal and can be attached to a bottom surface of the roof panel 1 for example by welding in case the roof panel's bottom surface is made of metal, with adhesive, screw fastening or rivets. Regarding the embodiments shown in the figures and described above, it should be noted that the intention thereof is by no means to limit the invention in any way. A skilled artisan will be able to modify the presented embodiments with variations often obvious for such an artisan within the scope of protection defined by the appended claims.