EP0082776B1 - Method for the transformation of a roof truss, and roof truss elements for carrying out this method - Google Patents

Abstract

1. Process for altering a roof truss, the said truss (1) being situated between two gable walls (20, 21) - possibly pointed - and comprising a series of gable trusses (2) extending from one front wall (3) to another (4), being disposed at a short distance ("D") from each other between the said front walls so as to form the necessary supports for the roof, and consisting principally of a horizontal beam (5) called a "tie-beam" and two inclined wooden members (6, 7) called "principal rafters", which, in non-convertable rooves, are connected to each other by means of triangular elements such as braces (8, 9, 10, 11) supporting the principal rafters so that the latter can resist the bending stress to which they are subject on account of the weight of the roof, this alteration process being characterised in that, before the triangular elements of each principal rafter are removed, - a vertical slide (12) is firstly secured between the principal rafter (6, 7) and the tie-beam (5) of at least a plurality of gable trusses (2), - beams (15) are simultaneously introduced into the roof and engaged in the slides (12), the said beams having first been divided into a plurality of sections (16, 17, 18 and 19) and the ends of the beam (15) are secured in the gable walls (20, 21) respectively, the sections (16, 17, 18, 19) of the beam being joined by joining means (22, 23 and 24), under each of which is secured a strut (25, 26 or 27), - the base of each of the struts (25, 26 or 27) is then secured by one of the ends of two beam ties (31 and 32) the other ends of which are connected, at least indirectly, to those of the beam sections situated on both sides of the strut in question, - finally, the beam ties are brought into action and, by acting on the strut with which they form a triangle, support the beam, which in turn at least indirectly supports the principal rafters and the roof, which thus allows for the removal of the original triangle of the gable trusses (2) and then for the lining of the roof.

Description

The invention relates to a method of transforming a frame and to the frame elements with a view to implementing this method.

It applies to the transformation of the frames of non-convertible attics to develop these attics.

We know that these frames consist of a series of small farms extending from one facade wall to another, between which facades, these small farms are placed at a short distance from each other and are held together by spacers and bracing from one gable wall to another and on which trusses, the roof is supported.

The farmhouses mainly include a horizontal beam called "entry" therefore connecting the walls of the front and rear facades and two pieces of inclined wood called "crossbowmen", rising to the fact of the roof.

These farmhouses are however light and must therefore be reinforced.

Their reinforcements consist of a triangulation formed of elements of which some, working in traction from the top of the farmhouse, support the entry while the others, working in compression by taking support at the foot of the preceding, support, generally in their middle, rafters who would otherwise be too flexible to support the roof.

This triangulation, which is repeated at each farmhouse and which constitutes an obstacle to the development of the attic, can obviously not be removed, without other precautions, without jeopardizing the rafters, the cover and the ceiling.

In new works (French patent A-2 411 283), before covering, it is of course known and easy to provide beams extending from one gable wall to another and on which will support the rafters of small farms which, at less in the area capable of constituting the habitable part of the attic, can then be devoid of support triangulation.

During the transformation of existing constructions, it is obviously possible to discover the frame to allow the passage and the installation of the beams as well as the rectification of the farmhouses but this constitutes an extremely important and expensive work which, moreover, during a certain time, expose the rest of the construction to the weather.

In order to allow the removal of the triangulation without depositing the roof, it is known to place, beforehand, under the rafters, support pillars. Unfortunately, these pillars cannot, for their part, be supported on the entry which had not been planned for such a load but must therefore descend to the first concrete slab which it meets in construction and which generally constitutes the floor of the last floor of the construction in the rooms of which floor, these pillars cannot always be easily hidden by cupboards or partitions.

One result that the invention aims to obtain is a frame transformation process which, without endangering the rafters and the cover, does not require either depositing this cover or providing under the rafters pillars which, for their support, must descend to a concrete slab which, moreover, it too was not intended for such a load.

• - tout d'abord, on fixe entre l'arbalétrier et l'entrait, d'au moins plusieurs fermettes, une coulisse verticale, composée de pièces de bois, dites »bracons«, solidarisant l'arbalétrier et l'entrait,
• - dans le même temps, on apporte dans le comble et on engage dans les coulisses des poutres que l'on a préalablement scindées en plusieurs tronçons et on scelle dans chacun des murs pignons l'une des extrémités de la poutre dont on relie les tronçons par des moyens de liaison sous chacun desquels on a fixé un poinçon,
• - ensuite, on saisit la base de chacun des poinçons par l'une des extrémités de deux tirants dont, au moins indirectement, on relie les autres extrémités à celles des tronçons de poutre situés de part et d'autre du poinçon considéré,
• - enfin, par manoeuvre de tendeurs appropriés, on fait agir les tirants qui, par réaction sur leur poinçon avec lequel ils forment une triangulation, soutiendront la poutre qui elle-même alors, au moins indirectement, soutiendra les arbalétriers, la toiture et les entraits,
• - après contrôle de la levée de la toiture, on dépose alors la triangulation initiale des fermettes puis on habille le comble.

To this end, the subject of the invention is a method of the aforementioned type, in particular characterized in that before removal of the triangulation elements from each crossbowman:

• - first of all, a vertical slide, made up of pieces of wood, called "bracons", is fixed between the crossbowman and the entry, at least several small farms, joining the crossbowman and the entry,
• - At the same time, we bring in the roof and we engage in the slides beams that have been previously split into several sections and we seal in each of the gable walls one of the ends of the beam whose sections are connected by connecting means under each of which a punch has been fixed,
• - then, the base of each of the punches is grasped by one of the ends of two tie rods, of which, at least indirectly, the other ends are connected to those of the beam sections situated on either side of the punch considered,
• - finally, by maneuvering suitable tensioners, the tie rods are made to act, which, by reaction on their punch with which they form a triangulation, will support the beam which itself then, at least indirectly, will support the crossbowmen, the roof and the ties ,
• - after checking the lifting of the roof, the initial triangulation of the trusses is then deposited, then the roof is dressed.

It also relates to the structural elements for the implementation of this process.

• - figure 1: un comble non aménageable avant la transformation selon le procédé de l'invention,
• - figure 2: ce comble après sa transformation selon le procédé de l'invention,
• - figure 3: une coupe selon Ill-lll de la figure 2,
• - figure 4: à plus grande échelle, un détail d'une fermette transformée.

The invention will be clearly understood with the aid of the description below, given by way of nonlimiting example, with reference to the attached drawing, which schematically represents:

• FIG. 1: an attic which cannot be converted before transformation according to the method of the invention,
• - Figure 2: this roof after its transformation according to the method of the invention,
• FIG. 3: a section along Ill-III of FIG. 2,
• - Figure 4: on a larger scale, a detail of a transformed farmhouse.

Referring to the drawing, it can be seen that the frame 1 comprises a series of small farms 2 extending from one front wall 3 to another 4 between which façades 3, 4, these small farms are placed at a short distance "D" from each other, and on which the roof (not shown) is supported.

The farmhouses 2 mainly comprise a horizontal beam 5 called "enter" connecting the walls of the facades 3, 4 and two pieces of inclined wood called "crossbowmen" 6, 7 rising to the roof ridge.

The load "P" of the roof biases these rafters 6, 7 which, like the ties, must therefore be supported.

For this purpose, before transformation, the crossbowmen 6, 7 and the entry 5 are connected together by elements 8, 9, 10, 11 forming a triangulation.

• - tout d'abord, on fixe, entre l'arbalétrier 6 et/ ou 7 et l'entrait 5 d'au moins plusieurs fermettes 2 et de préférence de toutes les fermettes 2, une coulisse verticale 12 formée par l'interstice entre deux pièces de bois 13, 14 dites »bracons«, fixées chacune par leurs extrémités à l'entrait et à l'arbalétrier correspondant, par tout moyen connu tel que clouage, vissage, agrafage, rivetage, boulonnage ou même soudure dans le cas de fermettes métalliques,
• - dans le même temps, on apporte dans le comble et on engage, dans les coulisses 12, des poutres 15 que l'on a préalablement scindées en plusieurs tronçons 16,17,18,19 chacun de dimensions réduites en fonction des possibilités d'accès et on scelle dans chacun des murs pignons 20, 21, l'une des extrémités de la poutre 15 dont on relie les tronçons 16, 17, 18, 19 par des moyens de liaison 22, 23, 24, sous chacun desquells on fixe un poinçon 25,26 ou 27,
• - ensuite, on saisit la base de chacun des poinçons par l'une des extrémités de deux tirants 31, 32 dont, directement ou indirectement, on relie les autres extrémités aux extrémités des tronçons de poutre situés de part et d'autre du poinçon considéré,
• - enfin, on place un cordeau témoin entre les pignons et on trace des repères sur chaque fermette, puis on agit sur les tirants qui, par réaction sur leur poinçon avec lequel ils forment une triangulation, soutiendront la poutre qui, elle-même, pourra alors directement ou indirectement soutenir les arbalétriers et tant la toiture que le futur plancher.

According to an essential characteristic of the method according to the invention, before removing the triangulation,

• - First of all, a vertical slide 12 formed by the gap between two is fixed between the crossbowman 6 and / or 7 and the entry 5 of at least several farms 2 and preferably of all farms 2 pieces of wood 13, 14 called "bracons", each fixed by their ends to the tie and the corresponding crossbowman, by any known means such as nailing, screwing, stapling, riveting, bolting or even welding in the case of small farms metallic,
• - At the same time, we bring in the roof and we engage, behind the scenes 12, beams 15 that have been previously divided into several sections 16,17,18,19 each of reduced dimensions according to the possibilities of access and one seals in each of the gable walls 20, 21, one of the ends of the beam 15 of which the sections 16, 17, 18, 19 are connected by connecting means 22, 23, 24, under each of which one fixes a punch 25, 26 or 27,
• - Then, the base of each of the punches is grasped by one of the ends of two tie rods 31, 32 of which, directly or indirectly, the other ends are connected to the ends of the sections of beam located on either side of the punch considered ,
• - Finally, we place a witness line between the gables and we draw marks on each farm, then we act on the tie rods which, by reaction on their punch with which they form a triangulation, will support the beam which, itself, can then directly or indirectly support the rafters and both the roof and the future floor.

As soon as the titration has risen by at least a few millimeters, after a possible reinforcement of the floor, the elements 8, 9, 10, 11 are then allowed to be removed, from the initial triangulation which has become useless.

The vertical slides 12 will be maintained to avoid any lateral displacement of the beam and its tensioning system.

These slides and / or the beams 15 can moreover serve as a support for the covering 37, of the vertical walls of the room to be fitted out, such as plasterboard, plywood, chipboard, etc. and to support, if need is, a cross member 38 which will receive reinforcements 39 of floor 40. This reinforcement can be constructed in the same way as it can 15.

The covering will then mask all this framework.

The floor reinforcements may be designed in several sections connected and subtended in a manner similar to the beam 15.

In addition to the transformation process, the invention also relates to the slides 12 and the beams 15 as well as the elements which compose them and which therefore ensure the implementation of the process.

In this regard, the connecting means 22, 23, 24 of the sections of beams 16, 17, 18, 19 may consist of articulation axes but, preferably, they will consist of simple forks carried at the head of the punches 25, 26, 27 in which the ends of said sections are simply deposited and placed in abutment one on the other.

As for the tensioners 41 of the tie rods, the sections of which may be circular or prismatic, they may advantageously consist of a part provided with threads with opposite pitch.

For their assembly at the return points, the ends of the tie rods will preferably be provided with a removable means such as a bolt or a hook engaging in an eyelet of a tab.

Although the invention has been described from a two-slope roof, it can obviously, even if the recovered living area is smaller, apply to roofs with more than two slopes, or some of the beam sections then being inclined to transfer onto the top of the gables, the load of the farms.

Claims (6)

1. Process for altering a roof truss, the said truss (1) being situated between two gable walls (20, 21) - possibly pointed - and comprising a series of gable trusses (2) extending from one front wall (3) to another (4), being disposed at a short distance (»D«) from each other between the said front walls so as to form the necessary supports for the roof, and consisting principally of a horizontal beam (5) called a »tie-beam« and two inclined wooden members (6, 7) called »principal rafters«, which, in non-convertable rooves, are connected to each other by means of triangular elements such as braces (8, 9, 10, 11) supporting the principal rafters so that the latter can resist the bending stress to which they are subject on account of the weight of the roof, this alteration process being characterised in that, before the triangular elements of each principal rafter are removed,

- a vertical slide (12) is firstly secured between the principal rafter (6, 7) and the tie-beam (5) of at least a plurality of gable trusses (2),

- beams (15) are simultaneously introduced into the roof and engaged in the slides (12), the said beams having first been divided into a plurality of sections (16, 17, 18 and 19) and the ends of the beam (15) are secured in the gable walls (20,21) respectively, the sections (16,17,18,19) of the beam being joined by joining means (22, 23 and 24), under each of which is secured a strut (25, 26 or 27),

- the base of each of the struts (25, 26 or 27) is then secured by one of the ends of two beam ties (31 and 32) the other ends of which are connected, at least indirectly, to those of the beam sections situated on both sides of the strut in question,

- finally, the beam ties are brought into action and, by acting on the strut with which they form a triangle, support the beam, which in turn at least indirectly supports the principal rafters and the roof, which thus allows for the removal of the original triangle of the gable trusses (2) and then for the lining of the roof.

2. Truss elements for carrying out the alteration process according to claim 1, characterised in that they comprise at least one beam (15) formed by a pluralty of sections (16, 17, 18, 19) which are joined to one another by joining means (22, 23, 24), each of which are secured to the head of a strut (25, 26 or 27), to the base of which two beam ties (31 and 32) are secured by one of their ends, their other ends being at least indirectly secured to those of the sections situated on both sides of the strut in question.

3. Elements according to claim 2, characterised in that the joining means (22, 23, 24) which are secured to the head of the struts (25, 26, 27) each comprise a single fork in which the ends of the sections of the corresponding beam are disposed and placed so that they rest one upon the other.

4. Elements according to claim 2, characterised in that they comprise slides (12) which are formed by the space left between two vertical members which are secured at their ends between their principal rafters and tie-beam.

5. Elements according to claim 2 or 4, characterised in that they cocmprise cross pieces (38), which support the floor (40) by means of reinforcements (39).

6. Elements according to claim 5, characterised in that the support reinforcements (39) of the floor (40) are designed in the same manner as the supporting beam (15) of the principal rafters.

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