EP0668953A1

EP0668953A1 - Process and devices for changing the vertical distance between the roof truss and the top ceiling of a building.

Info

Publication number: EP0668953A1
Application number: EP94901792A
Authority: EP
Inventors: Leonhard Hopf
Original assignee: KLAUS BAU GmbH
Current assignee: KLAUS BAU GmbH
Priority date: 1992-11-14
Filing date: 1993-11-12
Publication date: 1995-08-30
Anticipated expiration: 2013-11-12
Also published as: PL308993A1; EP0668953B1; ATE135077T1; CZ124295A3; DE4238484C2; WO1994011596A1; DE4238484A1; HU217947B; HUT71663A; HU9500987D0; AU5624094A

Abstract

In order to increase the vertical distance between the roof truss (1) and the top ceiling (2) of a building so that a habitable attic may be created, the roof truss (1) is detached from the building, lifted up as a single piece in its totality by means of lifting units (6) and guided in the lifting direction by guiding elements (18) which act as supports for the lifted roof truss at least until the outer walls of the building are sufficiently raised to bear the roof truss.

Description

Method and devices for changing the height distance of a roof structure from the top floor of a building

The invention relates to a method for changing the height distance of a roof structure from the top floor of a building and devices suitable therefor.

The subsequent loft expansion often requires an increase in the attic. For this it was previously necessary to remove the old roof truss and replace it with a new roof truss after pulling in a so-called knee stick. This is time and material consuming.

From FR-PS 2 540 543 it is known to raise a roof truss to enable the roof extension by means of hydraulic lifting units, then to pull up the outer walls of the building and finally to connect the roof truss to the raised outer walls. The roof truss is not stably guided during lifting, so that wind forces or other one-sided loads can lead to dangerous situations. Only after lifting the roof structure is secured by pairs of lockable telescopic supports and tensioning cables that run diagonally towards each other. However, this securing is inadequate due to the flexibility of the tensioning cables. If an adjustment of the raised roof truss is necessary, the supports and the tensioning ropes must be released so that the roof chair rests only on the lifting units, which cannot perform any management functions.

Proceeding from this, it is therefore the main object of the present invention to provide a method and devices for reliably guiding the roof structure during lifting and for supporting the raised roof structure and the lifting units.

The procedural solution to this problem is that the roof structure is guided in the lifting direction during the lifting process and remains in engagement with the guides beyond the lifting process, which are blocked after the lifting process has ended and form supports for the raised roof structure.

Lateral forces acting on the roof structure are absorbed by the guidance in the lifting direction. The fact that the guides form supports for the raised roof structure, the lifting units can be removed and used for another purpose. The guides preferably remain in the blocked state as static elements in the construction, as a result of which the outlay for removing them is avoided.

To stabilize the roof truss during the lifting process and to distribute the lifting forces, it is advisable to extend auxiliary supports in the roof truss in the longitudinal direction before lifting. to insert purlins, via which the lifting forces are transmitted to the roof structure.

The guide units for the roof structure each have two parts that can be moved against each other, of which the first part is a vertical column that can be attached to the building and the second part is a guide element that can be attached to the roof structure, with means for fixing the column relative to the roof structure after the Lifting process, for example by connecting the column with its guide element, are provided. This enables a particularly stable guidance in

Stroke direction. Even when the roof truss is raised, the guide units prevent the roof truss from shifting transversely to the lifting direction.

The two parts of each guide assembly can interlock telescopically. However, such telescopes are comparatively valuable facilities that require high investments. It is therefore expensive if the telescopes are left as lost devices in the building to increase the static safety. Another disadvantage is the fact that the stability of telescopic telescopes decreases with increasing extension length. Therefore, according to a further proposal of the invention, it is provided that the guide units each have a vertical column that can be attached to the building and a guide bracket that can be fixed on the roof frame and that surrounds the column. After the height change has been made the columns are blocked relative to the roof structure, preferably by connecting them to their guide bracket, so that they form rigid support members. Such guide units are simple and inexpensive parts that can remain in the building as lost components. Another advantage can be seen in the fact that the stability of these guide assemblies is the same over the entire guide height due to the one-piece design of the columns. A risk of wobbling and the associated risk of buckling are therefore not to be feared. The pillars, which protrude upward from the roof truss before lifting it, can, if necessary, simply be cut flush with the roof truss, making it possible to provide certain standard lengths for the pillars. The adaptation to the individual case is then carried out by means of the capping process.

As mentioned at the beginning, it is advisable to pull auxiliary greases into the roof structure before lifting them, which the lifting units will engage. It is preferable to install a medium auxiliary grease below the ridge and auxiliary grease that is symmetrical to the ridge. The medium auxiliary purlin prevents the roof truss from bending. After the roof has been raised, the medium auxiliary grease, which is outside the area required for the loft extension, can remain in the roof structure, thus strengthening it permanently. The side auxiliary greases can be removed. To support the lifting units on the auxiliary greases, the lifting units are provided with support heads, each have a channel open upwards and in the longitudinal direction of the auxiliary purlins for receiving the auxiliary purlins.

The side auxiliary purlins are expediently articulated releasably to the rafters in order to enable vertical alignment regardless of the roof pitch. For this purpose, the lateral auxiliary purlins are provided with articulated bearings, each of which has an upper part which can be detachably attached to a rafters and a lower part which is pivotably connected to it and which is provided with a channel which is open at the bottom and which is open to accommodate an associated lateral auxiliary purlin of the associated support head is aligned. To prepare the roof lift, the spherical bearing obex parts are first mounted and aligned on the relevant rafters. The pendulum-suspended lower parts automatically adjust themselves vertically, regardless of the existing roof pitch, so that the auxiliary greases picked up on the lifting units can be easily inserted into the channels of the lower parts.

The lifting units can optionally be provided with a directly attachable support head or with an extension that supports the support head and can be connected to the piston rod. These measures result in a modular construction of the lifting units and enable the use of the same hydraulic cylinders regardless of the required working height. The auxiliary purlins can each consist of several, preferably two, individual carriers arranged next to one another, preferably with a double-T cross-section. The individual girders can be composed of shorter girder sections, it being possible for the abutting points of the two girders to be arranged offset with respect to one another.

Some embodiments of the invention are described below with reference to the drawings. It shows:

1 is a schematic representation of an upper part of the building in section with roof truss lifting and guiding devices positioned in accordance with a first exemplary embodiment, the roof truss being shown in the left half in the non-raised state and in the right half in the raised state,

2 shows a representation similar to FIG. 1 of a roof truss with auxiliary purlins running in the longitudinal direction in the non-raised state and with roof truss lifting and guiding devices according to a second exemplary embodiment,

3 shows the roof truss of FIG. 2 in the raised state,

Fig. 4 is a partial view of a mountable on the building

2, FIG. 5 is a top view of the guide element of FIG. 4,

FIG. 6 is a view of the guide element from FIG. 4 assigned guide bracket to be attached to the roof structure.

Fig. 7 is a view of one with a medium auxiliary grease

2 cooperating lifting unit on a larger scale,

Fig. Ss a view of a side greases articulated on the roof structure according to FIG. 2 and a lifting unit interacting with them on a larger scale, and

9 shows a section along line 9-9 in FIG. 8.

The roof truss 1 shown in FIG. 1 initially rests, as shown on the left half of FIG. 1, on a floor extension 3 which does not protrude from the top floor 2 of an assigned building, or only slightly above it , as indicated on the right half of Fig. 1 by a knee stick 4 shown with broken lines. For this purpose, the existing roof truss 1 is removed from the floor approach 3 and raised by a corresponding amount. Of course, it would also be conceivable to lower a roof truss accordingly if the knee is lowered.

To carry out the change in height of the roof structure 1, a lift device described in more detail below is used, which is first brought into position. Then the anchoring of the roof truss 1 to the building, for example in the form of the roof truss 1 with the floor approach 3 connecting Screwed, loosened. Likewise, all permanently installed connections such as chimney surrounds, gutters, downpipes, electrical lines and the like are dismantled or extended. The roof truss 1 is then raised or lowered overall in the assembled state and in the roof covering left in place, that is to say as one part. In the example shown, the roof structure 1 is first raised and then held in the raised position so that the knee stick 4 can be pulled up. As soon as this is the case, the roof structure 1 can be anchored on the knee stick 4. If a roof truss is lowered, it is first raised from the existing knee stick so that it can be removed to the desired residual size. As soon as this has been done, the roof structure is lowered onto it and anchored to it. To during the lifting or lowering process or in the raised

Position to avoid a displacement of the roof structure 1 transversely to the lifting direction, the roof structure 1 is guided in the vertical lifting direction and is left in engagement with the guide at least until it is received on the raised or worn knee block 4.

To raise the roof structure 1, several hydraulic cylinder-piston units 6, which can be set up independently on the top floor ceiling 2, are provided, the extendable piston rods 7 of which can be brought into engagement with the roof structure 1. The number of lifting units used is in the form of the cylinder-piston units 6 provided here according to the type and size of the roof structure. In any case, such a number is provided that the roof truss 1 can be raised evenly in the assembled state.

The lifting units 6 are placed in such a way that the stress on the roof truss 1 is as uniform as possible. For roof trusses of normal design, it is sufficient if the lifting units are placed at a distance of three to five rafters. The lifting units can engage on the beams running transversely to the rafters, as here on the ridge beam 8 or the roof purlins 9 running parallel thereto. A direct attack on individual rafters is also conceivable. In these cases, a wedge-like attack console 10 can be attached.

The hydraulic lifting units 6 are connected to a pressure source by pressure lines 11. This contains a pump 13 which can be driven by a motor 12 and which is connected on the one hand to a tank 14 for the hydraulic fluid and on the other hand to a distribution station 15 to which the pressure lines 11 are connected. The entire pressure generating device is preferably on the top

Floor ceiling 2 placed, but can also be arranged outside the building.

The lifting process is carried out in several stages. First, the roof structure 1 is roughly on the ge in the course of a rough stroke desired height brought. To carry out the rough stroke, all lifting units are put into operation together, which is accomplished by a control device 16 assigned to the distribution station 15. The roof truss 1 is then aligned, which is accomplished by commissioning individual lifting units or lifting unit groups. For this purpose, manually operated switching valves 17 are provided in the pressure lines 11. The adjustment movement is expediently carried out in a slower gear than the rough stroke movement. The basic position of the lifting units with retracted piston rods is shown in the left half of the drawing, the end position with extended piston rods in the right half of the drawing.

In order to absorb forces directed transversely to the stroke direction and thus to avoid a corresponding displacement of the roof structure 1, guide elements 18 are provided which are provided with guide surfaces running in the stroke direction. These guide elements 18 are designed here as extendable telescopes, the stationary lower part 19 of which can be fixed on the building, here on the top floor ceiling 2, as indicated by screws 20, and whose upper part 21 guided in the lower part can be fixed on the roof frame 1 with its upper end , as is indicated here by a holding shoe 22 which can be screwed to the roof structure 1. The guide elements 18 are without a drive. Your tops 21 will be when lifting the

Roof truss 1 extended from its lower parts 19. The guide elements 18, which can be set up independently of one another, are provided in such a number that the transverse forces which occur are absorbed; it is usually sufficient for this purpose if guide elements are provided in the region of every second rafter.

When the desired height has been reached, rigid steel supports 23 can be used in addition to the lifting units, if necessary. These can be one-part supports or two-part supports provided in a manner known per se with an adjusting thread. As soon as a sufficient number of such supports 23 have been brought into position, the lifting units 6 can be retracted and removed. The roof structure 1 then rests on the supports 23. The guide elements 18 expediently remain in position in order to prevent the roof structure 1 resting on the supports 23 from extending transversely to

Can shift stroke direction. The upper and lower parts of the guide elements 18 could, however, also be locked against one another, for example by means of pins etc., so that they serve as rigid supports. In this case, the

Support 23 is omitted. The lifting units 6 can now be dismantled together with the associated pressure generating device and used for further use on a new construction site. The supports 23 and the guide elements 18 remain in position until the knee stick 4 is raised. The roof truss 1 is then anchored thereon. Then the supports 23 and the guide elements 18 can also be removed. The telescopes 18 provided as guide units in the example according to FIG. 1 are relatively expensive, so that leaving them in the raised roof structure is uneconomical. In order to increase the economy and to avoid the costs of expanding the guide units, in the second exemplary embodiment according to FIGS. 2 to 9, guide elements 18a are used for guiding the roof structure 1 during lifting or lowering, which are much cheaper, each one on the floor ceiling 2 have anchored vertical column 24 which interact with a guide bracket 25 which can be fixed on the roof structure 1. As can be seen from FIGS. 2 and 3, the guide elements 18a are placed in the lower roof truss area, ie in the knee stick area. The number of guide elements 18a used is chosen so that the expected ones

Shear forces can be absorbed. As a rule, it is sufficient if a guide element 18a is assigned to every third rafter 1a.

Each vertical column 24 is received on a foot 26 which is anchored to the floor ceiling 2. As shown in FIGS. 4 and 5, the column 24 can be designed as a rectangular tube section, but can also have a different cross section. The foot 26 can be formed by a rectangular plate which is provided with holes 27 for receiving fastening screws. The foot 26 is placed on the raw concrete of the floor ceiling 2 and aligned so that the column 24 is perpendicular.

For this purpose, the screed of the floor ceiling 2 is removed at the points in question and the exposed concrete surface is leveled with leveling compound. The screws assigned to the holes 27 can then be set, to which the foot 26 is then anchored.

In order to increase the stability of the connection of the column 24 to the foot 26, the plate forming the foot 26, as further shown in FIGS. 4 and 5, is provided with webs 28 flanking the column 24. These can be designed as symmetrically arranged U-rail sections which receive the column 20 between them, which are welded to the column 24 and to the foot 26 or are connected in some other way.

The columns 24 are, as shown in FIGS. 2 and 3, mounted so that they rest with the flank of their rectangular cross-section on the side flank of a respectively associated pair la. After such assembly of the columns 24, the guide bracket 25 are attached to the relevant rafters la. As can be seen from FIG. 6, the guide brackets 25 have a central U-shaped pocket 29 and fastening tabs 30 projecting laterally therefrom. The pocket 29 has an outer dimension of the cross section of FIG

assigned pillar 24 corresponding clear width plus running play. Each guide bracket 25 is with its fasteners supply flags 30 attached to the associated rafters la and thus limits together with this a guide channel through which the column extends.

The holding lugs 30 are fastened to the rafters 1 a by nails or screws and are provided with corresponding ones

Provide holes 31. The guide bracket 25 are narrower than the rafter thickness in the example shown, so that the holding tabs 30 are opposite each other at the same height. Of course, a height offset corresponding to the inclination of the rafters would also be conceivable. In the area of the web of the middle pocket 29, a further bore 32 is provided, by means of which pinning or screwing between the guide bracket and the associated column is possible.

As can be seen in FIG. 2, the columns 24 initially protrude beyond the roof structure 1 by at least the length corresponding to the lifting height. To make this possible, the roof is opened at the relevant points. The length of the columns 24 thus corresponds at least to the original distance of the

Rafter top from the floor ceiling 2 in the area of the associated guide bracket 25 plus the desired lifting dimension. After the lifting process has been carried out, the guide brackets 25, as already mentioned, are connected to the respectively assigned column 24. For this purpose, the columns 24 are each provided with a bore aligned with the bore 32 of the associated guide bracket 25, so that a plug pin or Screw can be inserted. In this way, the guide elements 18a become rigid support elements. Alternatively, the columns 24 can also be connected directly to the associated rafters. If the columns 24 still protrude from the roof truss 1 after the lifting process has ended, the projecting piece 33 (FIG. 3) is simply cut off flush with the top of the roof truss. This enables the use of standardized column lengths. After the columns 24 have been shortened accordingly, the roof is closed again.

The columns 24 blocked by connection to the guide brackets 25 or directly to the roof structure remain in position as rigid supports at least during the entire loft expansion. As a rule, however, the columns 24 are left in position to increase the static safety of the overall arrangement, which also avoids the expense of removing the columns. As soon as the roof structure 1 rests on the blocked pillars, the lifting units 6 can be removed.

In the example according to FIGS. 2 to 9, a plurality of auxiliary purlins 30, 31, which are to be drawn into the roof structure 1 before the change in height and are to be carried out, are provided, on which the lifting units 6a and 6b act.

In the example shown, a middle auxiliary grease 30 and two side auxiliary greases 31 are provided. The middle auxiliary purlin 30 is below the ridge, the lateral auxiliary Spfetten 31 are arranged in the lower half approximately between the lower quarter and half the length, preferably about a third of the length of the rafters la, so that there is an auxiliary purlin arrangement symmetrical to the ridge. The

Auxiliary greases 30, 31, as shown in FIGS. 7 and 8, each consist of two individual carriers 32 arranged next to one another, firmly connected to one another, here two double T carriers arranged next to one another. These can be made of wood or other material, such as metal, and can be designed as truss or full profile beams. The individual carriers 32 can be composed of successively arranged carrier sections of manageable length, the joints on both sides being expediently offset in length, so that each carrier section can be connected to two adjacent carrier sections and a stable structural unit results overall.

The lifting units 6a, 6b each comprise, as shown in FIGS. 7 and 8, a hydraulic cylinder 33 with an extendable piston rod 7, on each of which a support head 35a or 35b, which can be brought into engagement with the associated auxiliary purlins 30 or 31, is attached. The support heads 35a, 35b each consist, as can best be seen from FIG. 9, of a base plate 36 with projections 37 projecting vertically upward therefrom, which delimit a channel 38, the clear width of which corresponds to the width of the auxiliary greases 31. The projections 37 are in the example shown as in the form of corner pillars on the base plate 36 attached angle profile sections formed. The support heads 35a, 35b are brought into engagement with the respective associated auxiliary purlin 30 or 31 in such a way that it engages in the channel 38, as indicated by broken lines in FIG. 9. The hydraulic cylinders 33 are placed on the floor ceiling 2 on large base plates 39 for the purpose of distributing the load as large as possible, the edge length of which may correspond to approximately ten times the cylinder diameter.

The lifting units 6a, 6b have a modular structure. The same hydraulic cylinders 33, which are thus interchangeable, can therefore be used for all lifting units. The lateral auxiliary purlins 31 are normally placed in such a way that the hydraulic cylinders 33 reach the height required in the area of the lateral auxiliary purlins 31 without extending their piston rods. The support heads 35b can therefore, as shown in FIG. 8, be received directly on the piston rods 7.

These are each provided with a threaded pin 40 at their upper end. The base plates 36 of the support heads 35b have a threaded bushing 41 projecting downward, so that the support heads 35b can each be screwed directly onto a piston rod 7.

With the lifting units 6a assigned to the middle auxiliary purlins 30, an extension 7a of the piston rod 7 is required, as shown in FIGS. 2 and 7. This is done in the same way as a support head 35b is connected to the piston rod 7 provided with the threaded pin 40. For this purpose, a connection bush 43 which can be screwed onto the threaded pin 40 is provided, into which a tubular attachment 44 can be inserted, onto which the support head 35a can be placed. In the example shown, as further shown in FIG. 7, the support heads 35a are provided with a pin 45 which projects downward from their base plate 36 and which can be inserted into the attachment 44. To secure the plug connections at the upper and lower ends of the attachment 44, pins 46 which can be pushed through associated through holes are used and are secured by means of a split pin. The pin 45 is provided with a plurality of through holes which are offset in terms of height relative to one another, as a result of which a rough height adjustment is possible. The top 44 is here provided at its upper end with two through bores offset by 90 °, so that the associated support head 35a can be arranged in two positions rotated by 90 °, which enables a high degree of freedom during installation.

First, the middle auxiliary grease 30 is installed. This is placed below the roof ridge on the generally existing ridge tongs 1b of the roof structure 1 and connected to them. The auxiliary grease 30 received on the ridge tongs 1b is located outside the space required for a roof extension and can therefore be left in the roof structure 1 forever. After the middle auxiliary purlins 30 have been fastened, the lifting units 6a assigned to them can be brought into position and placed against the auxiliary purlins 30 under slight pressure. The lifting units 6a are evenly stretched to the length of the

Auxiliary fats 30 distributed. As a rule, it is sufficient if these are provided at a distance of 3 to 4 meters.

After the middle auxiliary grease 30, the side auxiliary grease 31 can be brought into position. These are supported on rafters la via spherical bearings 48. As a rule, it is sufficient if in the area of every second rafter

Spherical bearing 48 is provided. First, the spherical bearings 48 are assembled for themselves. Thereafter, the lifting units 6b assigned to the lateral auxiliary purlins 31 are brought into position in rows and the associated lateral auxiliary purlins 31 are then picked up. The lifting units 6b can in turn be arranged at a distance of 3 to 4 meters. The lifting units 6b are initially in the retracted state, their support heads 35b being so far apart from the rafters that the auxiliary purlins 31 can be inserted without colliding with the spherical bearings 48. The lifting units 6b are then extended to such an extent that the auxiliary purlins 31 come into engagement with the respectively assigned spherical bearings 48. The lifting units 6b can also be easily driven under pressure. The spherical bearings 48, as can be seen from Fig. 8, consist of an upper part 49, expediently in the form of a detachably fastened to the rafters la, U-shaped bearing block in cross section, and a lower part 50 suspended from the upper part, expediently in the form of a cross section U-shaped console. The overlapping side flanges of the upper part 49 and the lower part 50 are provided with an aligned through-hole through which a pin 51 forming the pivot axis can be inserted, which can be secured by means of a split pin, so that there is a releasable articulated connection. The upper parts 49 can therefore first be assembled in a separate state. For this purpose, a laser device can be used which generates a laser beam, along which the upper parts 49, each associated with a side auxiliary purlin 31, are mounted at the same height. To make assembly easier, the upper parts 49 are provided on their web 49a, which can be brought into abutment on the underside of the rafters, with claws 53 flanking the rafters, the spacing of which can be slightly undersized compared to the width of the pairs, provided that a slight clamp fit is desired. The claws 53 can be provided with holes through which tacking pins 54 can be driven in, which enables reliable pre-assembly. For final fastening, the web 49a resting on the rafters la can be screwed on with hexagonal wood screws 55, which enables the spherical bearings 48 to be removed later. Adequate

Attachment of the upper parts 49 to the rafters can, however often already done by tongues 49b, which are bent out of the web 49a and dig into the rafters la.

After the assembly of the upper parts 49, the spherical bearings 48 are completed by attaching the lower parts 50. These each have two parallel, tab-like projections 56, which project downward from the ends of their web 50a, the clear distance of which corresponds to the width of the associated auxiliary purlins 31 and which accordingly limit a receiving channel for the auxiliary purlins 31, which is aligned with the channel 38. The protrusions 56, as can be seen in FIG. 9, extend between adjacent protrusions 37 on each side of the

Auxiliary greases 31 and are angled outwards at their lower end, which enables the auxiliary greases 31, which have been brought up from below, to be reliably run in.

After the above-described assembly of the auxiliary greases, the lifting units and the guide elements, the anchoring of the roof structure 1 on the building is loosened, as was stated at the beginning, and all permanently mounted connections are removed or extended. The roof truss can be activated by activating the

Lifting units 6a, 6b are raised.

When the desired height, here the position of the roof truss 1 shown in FIG. 3, has been reached, the guide elements 18a are blocked by the columns 24 ver with the associated guide brackets 25 or directly with the relevant rafters be bound. Normally, the blocked guide elements 18a can carry the raised roof structure 1 until the knee stick 4 is raised. The lifting units 6a, 6b can therefore be removed and used for other purposes. The same applies to the lateral auxiliary purlins 31 and the joint bearings 48 assigned to them. As mentioned above, the central auxiliary purlins 30 remain as a lost component in the roof structure 1. The guide elements 18a are used to increase the static

Security of the roof structure 1 preferably as lost

Components left in position, which also avoids the expense of dismantling the relatively inexpensive guide elements 18a.

1, 2 and 3 is based on an increase in the roof structure 1 by the height of the knee 4. However, it would also be conceivable to lower the roof truss 1 as a whole using the device according to the invention. A lowering may be necessary if an existing knee stick is subsequently to be removed in whole or in part. Here, the roof truss detached from the building is first raised slightly by means of the lifting units 6 and 6a, 6b and guided by the guide elements 18 and 18a, so that the knee can be removed by the desired amount. As soon as this has been done, the roof truss is lowered to the desired, lower level, the lifting units and preferably also the guide elements are removed, and finally the roof truss is anchored to the building again.

Claims

1.Procedure for increasing the height distance of a roof truss from the top floor of a building, first of all releasing the anchoring of the roof truss to the building, then lifting the roof truss as a unit by means of lifting units, then increasing the outer walls of the building and finally the roof truss being picked up thereon,

characterized in that the roof truss is guided in the lifting direction during the lifting process and remains in engagement with the guides beyond the lifting process, which are blocked after the lifting process has ended and form supports for the raised roof truss.

2. The method according to claim 1, characterized in that the guides remain in the blocked state as static elements under construction.

3. The method according to any one of the preceding claims, characterized in that extending in its longitudinal direction auxiliary purlins are installed in the roof structure, via which the lifting forces are transmitted to the roof structure.

4. The method according to claim 3, characterized in that a medium auxiliary grease is installed below the ridge, and that preferably symmetrically to the ridge at least two Lateral auxiliary purlins are provided, for example, over a medium rafter length.

5. The method according to claim 4, characterized in that the medium auxiliary purlins are releasably connected with ridge pliers and the lateral auxiliary purlins with individual rafters.

6. The method according to claim 5, characterized in that the lateral auxiliary purlins are articulated to the rafters.

7. The method according to claim 6, characterized in that first selected rafters are provided with spherical bearings which are aligned in height, and then the lateral auxiliary purlins recorded on lifting units are brought into engagement with the spherical bearings.

8. An apparatus for performing the method according to one or more of the preceding claims, with lifting units (6; 6a, 6b) which can be set up independently of one another on the building side and can be brought into engagement with the roof structure (1) and which can be driven together to lift the roof structure, characterized by Guide units (18; 18a) for the roof structure, each having two mutually displaceable parts (19, 21; 24, 25), of which the first part has a vertical column (19; 24) which can be fixed on the building (2) and the second Part a on Roof structure attachable guide element (21; 25) for the column, and means for fixing the first part relative to the roof structure after the lifting process.

9. The device according to claim 8, characterized in that the guide units (18) telescopically interlocking parts (19,21), of which one part (19) with the building (2) and the other part (21) with the roof structure (1) is connectable and can be locked against each other.

10. The device according to claim 8, characterized in that the guide units (18a) on the building (2) attachable vertical columns (24) and on the roof truss (1) attachable

Have guide brackets (25) encompassing columns and that means are provided for fixing the columns (24) relative to the roof truss after the roof truss has been raised.

11. The device according to claim 10, characterized in that the columns (24) have a rectangular cross section.

12. The apparatus according to claim 10, characterized by means for connecting the columns with their guide brackets.

13. An apparatus for performing the method according to one or more of claims 3 to 7, with independently adjustable lifting units which can be brought into engagement with the roof structure (1) (6a; 6b) and which are used for lifting the roof structure are drivable together, characterized in that the lifting units (6a; 6b) are assigned center and side auxiliary purlins (30 and 31) which run in the longitudinal direction of the roof structure (1) and can be connected to them, and that the lifting units are equipped with support heads (35a; 35b) are provided, each of which has a channel (38) open at the top and in the longitudinal direction of the auxiliary purlins for receiving the auxiliary purlins.

14. The apparatus according to claim 13, characterized in that the lateral auxiliary purlins (31) associated spherical bearings (48) are provided, each having a detachably attached to a rafters (la) upper part (49) and a pivotally connected lower part ( 50) which is provided with a channel which is open towards the bottom and which is aligned with the channel (38) of the associated support head (35b) for receiving an associated lateral auxiliary purlin (31).

15. The apparatus according to claim 13 and / or 14, characterized in that the support heads (35a, 35b) each have a base plate

(36) with upwardly projecting projections (37) delimiting the channel (38), and that from the lower part (50) of each spherical bearing (48) there are downwardly projecting projections (56) which are located between adjacent projections

(37) on each side of the side auxiliary purlin (31) concerned.

16. The device according to one of claims 13 to 15, characterized in that the lifting units (6a; 6b) for the middle auxiliary greases (30) and the lateral auxiliary greases (31) are identical extendable hydraulic piston-cylinder units, on the for the lateral auxiliary greases (30) the support head (35b) is placed directly and for the medium auxiliary purlins (30) the support head (35a) is placed over an extension element (7a).

17. The device according to one of claims 8 to 16, characterized in that the lifting units (6) are individually extendable.

18. Application of the method according to one or more of claims 1 to 8 and the device according to one or more of claims 9 to 16 for lowering a roof truss, the roof truss being held in its original position by the lifting units and after removal of the building's outer walls the desired amount is lowered and is guided in the lowering direction.