GB2496425A - Floor cassette with receiving means for securing a roof support. - Google Patents

Abstract

The floor cassette comprises: a floor panel 27 having a lower surface arranged for location on a wall; a planar upper surface; a number of side edges 28a, 28b and at least one wall plate 86a, 86b, but preferably two on opposite sides, which is arranged on the upper surface so that an outer edge of the plate corresponds to a side edge of the floor panel. The wall plate includes at least one rebate 88 to provide an abutting upper surface into which a projection of a roof support may press. The cassette is preferably made from a solid timber annular frame upon which a planar timber sheet is secured. The rebate or channel on the top layer panel may be arcuate or tapered. The roof supports may be joists, rafters or spandrels. Also claimed is a system which comprises the cassette and a roof support, the roof support comprising a first edge locating within an abutting against the recess/rebate on the planar floor sheet. Also claimed is a method of installing a roof on the floor cassette. A cassette may be mounted on a spandrel.

Description

FLOOR CASSETTE

The present invention relates to floor cassettes in building construction and in particular, though not exclusively, to a floor cassette for use in a roofing system and to a roofing system wherein ths floor cassette and roofing supports engage to provide distributed load bearing surfaces across the roof.

Until recently habitable room in the roof space of a building was only possible using trussed rafters or loose cut roofs.

Both of these methods provide structurally sound solutions but involve most of the work being performed on-site and at height.

Panelised roofs have been introduced in recent years and are now growing in popularity and sophistication. The principal drivers are speed cf construction, assured levels cf performance through improved qiality control, the desire fcr improved health and safety and the minimisanion of waste on-site.

One known system is Smartroof® produced by Smartroof Ltd and described in GB 2391026. This is a prefabricated, modular roofing system comprising main roof panels which can span the distance between gable ends and can be supported thereby and intermediate panels which do not span the whole roof and are supported by, and cooperate with, the main roof panels. One side of the roof system preferably comprises at least two main roof panels, one set of intermediate panels arranged between the main roof panels to provide window openings, an cave panel and an apex panel. The cooperating surfaces may extend across the full length of the panels. The roof is preferably attached by a tongue and groove system, wherein the groove is provided along a sloping edge at the gable ends, or spandrels if used, and the tongues are located on the ends of the roof panels. A method of assembling the roof using bracing means is also disclosed whereby a spandrel once affixed to the brickwork of the end walls of the building is braced to the side walls to prevent sideways movement during roof construction. In this roof system substantially all the weight of the roof is supported by the end walls as compared to other roofing systems where the weight of the panels is at least partially supported on the side walls which tends to force the side walls apart due to the lateral loading applied.

There are a number of disadvantages in this roofing system.

The panels must be manufactured to a high tolerance and the spandrels separated by an equally high tolerance, so that the tongue and grooves mate correctly. A considerable amount of screwing and nailing is required to restrain the roof panels from sliding down the roof line. This lateral loading down the pitch of the roof is increased by the use of closed roof panels which are made heavier by the inclusion of insulation and surrounded boarding. Additional time is required when the spandrels are craned into position, as the cranes must bear the weight of the spandrels until such time as the bracing arrangement is fitted.

GB 2475539 to NiTek Holdings, Inc. describes a method of constructing a roof on top of a building comprising; fixing two lower spandrels, one on each of the other two sides of the top of the building, the lower spandrels each having a trapezoidal shape having two parallel sides and two sloping sides; fixing ceiling panels to the upper sides of the spandrels to form a platform; fitting upper spandrels above the respective lower spandrels on the ceiling panels; and fitting gable to gable roofing panels to bridge the gap between the sloping sides of the spandrels to form a roof. The method may comprise constructing a small wall along two opposite sides oiff the top of the building and the ceiling panels may be closed panels with insulation. A groove may be provided in the sloping edge of one of the spandrels for locating the roofing panels. The roofing panels may comprise at least one flitch beam attached to the spandrel to transfer the load which may comprise a sheet of steel sandwiched between two wooden beams.

This roofing system uses The well-known piggy back' arrangement of spandrels and locates a ceiling between the lower and top-hat spandrels. While it identifies the disadvantages in the earlier patent application, it fails to mitigate some while introducing others. This roofing system describes the construction of two small timber walls on the side walls, these are matched to snubbed ends of the lower spandrels. It is not clear if these are tied together to form a brace, but it does require specially shaped spandrels. This roofing system also uses locators on the roof panels to lie in a groove along the sloping edge of the spandrel and thus has the same disadvantages to tight tolerances as the prior art roofing system, though the presence of, and the width of, the small wall may assist this, if it is constructed to a tight tolerance. The roofing panels are lighter weight than those detailed in GB2391026, having no insulation and the locators set the panels so as to be spaced apart from the spandrels.

This arrangement means that flitch beams are incorporated to screw the panels to the spandrels and transfer the load.

However, the beams add extra time and components to the construction, do not prevent the panels from sliding down the roof line during construction and provide a substantial air gap between the panels and the spandrels. This air gap must be filled to seal the roof, adding further time and construction materials. Additionally, insulation needs to be added to the roof panels and, although there is a greater space to add more insulation, this merely increases the load of the roof which is entirely transferred to the end walls.

An additional disadvantage is in the arrangement of the ceiling onto the lower spandrel. The ceiling cassette is designed to sit over the upper parallel sides of the lower spandrels and to looate in the groove on the sloping edges of the spandrels. This arrangement means that the roof panels cannot be fitted directly against the spandrels to create a seal as ceiling noggins are boated over the spandrels. The roofing panels reguire locators to span the ceiling noggins and as disoussed above, the resulting air gap provides disadvantages in construction.

It is an object of the present invention to provide a floor cassette for use in a roof of a building which distributes the load of the roof arrangement assembled thereon.

It is a further object of the present invention to provide a floor cassette for use in a roof of a building which supports roof joists and/or spandrels arranged thereon with at least a reduced reguirement for additional fixings such as nails and screws.

It is a further object of at least one embodiment of the present invention to provide a roofing system including a floor cassette which distributes the load of the roofing system across the building.

It is a still furoher object of at least one embodiment of the present invention to provide a method of constructing a roof of a building which is quicker and more efficient than the

prior art methods.

According to a first aspect of the present invention there is provided a floor cassette for use in a roof of a building, the floor cassette comprising a floor panel having a lower surface arranged for location upon a surface area on which a roof arrangement is to be provided; a substantially planar upper surface; a plurality of side edges and at least one wall plate wherein said wall plate is arranged on said upper surface suoh that an cuter edge of said wail plate corresponds to a side edge of said floor panel and an inner edge of said wall plate comprises at least one rebate to provide an abutting surface to support at least a portion of a roof support.

In this way, a floor cassette can be arranged in a roof being constructed such that the waIl plate retains and provides support to a roof support such as a joist or spandrel. In this way, the floor cassette distributes the weight of the joist or spandrel and any roof panels arranged thereon across the roof cassette. By distributing the weight, the effect of the weight of the roof arrangement on the structure it is built on. For example, the weight will be distributed so not focused mainly on one or two walls, or areas of walls, of a building or on castellated spandrels of a lower roof arrangement. In addition, the rebates act to provide support to said roof support therefore minimising, if not eliminating, the addition securing means, such as ties, supports, nails or screws, which are required as well as the manpower needed for the assembly of the roof when using such fastenings. The rebates further ensure that a snug secure arrangement is created during assembly of the roof such that there are minimal gaps left during construction which may need filled later.

Preferably the floor cassette is provided with wall plates arranged at opposing side edges of the floor panel. By arranging wall plates to oppose one another the load of the structures secured thereto will be distributed more effectively across the whole floor cassette.

The lower surface of the floor cassette may correspond with and be suitable for arrangemenu on an upper surface of walls of a building on which a roof has to be constructed. Such an assembly will ensure that the floor cassette acts to protect any specific area of the building wails from being subjected to undue direct pressure from an assembled roof as the load of the roof will change from acting outwards on the walls to downwards on the walls. In effect, this will minimise the effect of spread on walls of the building caused by the load of the roof arrangement.

Alternatively, the lower surface of the floor cassette may corresponds with and be suitable for arrangement on an upper surface of a pair of spandrels of a lower roof arrangement on which an upper roof arrangement has to be constructed. The inclusion of a floor cassette in such a piggy back roof assembly will ensure that the load of the upper roof arrangement will be spread more evenly across the lower roof arrangement.

Optionally, the floor cassette may be formed of a solid timber rectangular annular frame upon which a planar timber sheet is secured. In this way, the solid timber rectangular frame will form the lower surface and correspond to the walls of the building, or the upper spandrel surfaces, on which it will be placed for a roof arrangement to be built on the upper surface of the planar timber sheet.

Each rebate may have a tapered profile. A tapered profile will mean that the portion of the roof support received into, and abutting against, the rebate may be wedged into position by the weight of the roof assembly. This will result in a more secure construction and ensure effective support is provided by the floor cassette assembly.

Preferably, each rebate has an abutting surface which is arcuate in profile. By having a rounded abutting surface, the rebate is able to provide a greater degree of tolerance in the positioning of the portion of the abutting roof support and can facilitate the guiding of the roof support into position in the rebate of the floor cassette.

The roof supports may be roof joists or rafters, or spandrels.

This means the cassette can provide support to either or both of spandrels located at the outer limits of the roof assembly and rafters arranged across the roof arrangement width and is therefore able to distribute load effectively whichever type of roof assembly system is being used.

According to a second aspect of the present invention there is provided a roofing system for a building, the system comprising at least one floor cassette according to the first aspect and at least one roof support, die roof support including a first edge to locate against the abutting surface of the floor cassette whereupon the floor cassette bears the weight of the roof support at the rebate.

In this way, the roof cassette supports the weight of the roof support and any roofing components arranged thereon such that the weight is then distributed across the floor cassette thus

S

reducing lateral or outward pressure of the roof arrangement on the waits of the building.

Preferably, the roof support is a spandrel and further preferably there is provided a pair of spandrels. A roof oassette which supports roof spandrels will help reduoe the pressure on the walls of the building created supporting the spandrels and roof panels thereon directly. Instead, the roof cassette will spread the weight more evenly across the building wails. In addition, the use of a spandrel roof system will support roof panels spanning across the width of a building therefore offering unimpeded use of the attic space.

The roof support may be a rafter and preferably there is provided a pluraiity of rafters. Such an arrangement provides distribution of the weight of the rafters and roof paneis supported thereon across the floor cassette and therefore building as weil as providing a roof arrangement which facilitates provision of features such as windows, access panels and/or hatches in roof panels arrangement between adjacent rafters.

According to a third aspect of the present invention there is provided a method of constructing a roof of a building comprising the steps: (a) iocating a fioor cassette according to the first aspect on a suitable surface area; (b) locating at least one roof support to correspond with a rebate of the fioor cassette; (c) directing said roof support towards a side edge of a floor panel of the fioor cassette such that the first edge of said roof support meets the abutting surface of the rebate; and (d) supporting said roof support weight at the abutting surface of the rebate and distributing said weight.

In this way, roof supports can be located and supported simply by using a crane, thus removing the need for highly skilled workers at the location of building construction to locate and affix roof supports to the building structure. This saves considerable time and cost in the build and also increases safety.

Preferably, the method includes the step of locating a roof support and corresponding flocr cassette rebate at opposing sides of a roof system. Such an arrangement will ensure the weight of the assembled roof is distributed more effectively across the whole of the building as well as minimising the potential for damage to the building walls as the force of the weight on the building is directed downwards and not laterally.

Preferably, the method includes the step of locating a spandrel at opposing sides of the roof cassette such that they are supported by abutting against the wall plates of the floor cassette. This arrangement ensures the weight of roof panels supported on the spandrels is distributed across a greater area.

The method may further include the step of locating roof joists such that they are supported by abutting against the wall plates of the floor cassette.

Preferably, the method may further include the step of locating a second floor cassetne on an upper surface of said spandrels. Such a "piggy back" roof system arrangement can further help distribute the weight of the roof arrangement as well as better defining a useable ceiling space and providing further support in the roofing system.

Embodiments of the present invention will now be described, by way of example only, in which: Figure 1 is an expanded illustration of a roof system for a building including a floor cassette according to an embodiment of the present invention; Figure 2 (a) is a perspective view of a floor cassette according to further embodiment of the present invention; Figure 2 (b) is a cross section of a portion of a floor cassette according to a further embodiment of the present invention; Figure 3 is a perspective view of a portion of a roof panel according to a further embodiment of the present invention; Figure 4 (a) is a cross section of a roof system according to a further embodiment of the present invention; Figure 4 (b) is a detail of a portion of Figure 4 (a) ; and Figure 5 is a perspective view of a roof system according to a yet further embodiment of the present invention.

Referring initially to Figure 1 of the drawings there is illustrated a roofing system, generally indicated by reference numeral 10, comprising floor cassette, spandrels 12a,b and roofing panels 14a-g, according to an embodiment of the present invention.

Roofing system 10 is located upon a building 16 formed of end walls 18 (one shown) and side walLis 20 (one shown) . End and side walls 18,20 are typically constructed of block or brickwork and form the storeys of the building 16 as is known in the art. At the roof level 22, a floor level 24 is constructed formed of one or more floor cassettes 26, in this case, the roofing system is formed with one floor cassette 26.

Floor cassette 26 comprises an array of joists (not shown) which are braced together preferably with a Strongbridge® recessed brace. Boarding is nailed to the upper surface to create a floor 27 and rim boards are arranged around the perimeter, such that when the floor cassette 26 is lifted onto the building 10, the rim 28 aligns with the outer face 30 of the walls 18,20. The floor cassette 26 can have an access hole arranged there through for positioning of a staircase or a hatch.

The floor cassette 26 is further provided with, in this case, two wall plates 82 (one shown) arranged on the upper surface, or floor, 27 with each wall plate 82 having an outer edge 84 which corresponds with the rim 28 aligned with walls 20. The wall pate 82 is further provided with an inner edge 86. Floor cassettes speed up construction time on-site, reduce the requirement to have skilled labour on-site to construct a floor and create minimal on-site waste.

Each spandrel 12 is formed of three timbers 32, 34,36 placed in a triangular arrangement with a base timber 32 and two inclined timbers 34,36 meeting at an apex 38.

The roofing system 10 is further provided with a plurality of panels l4a-g. As can be seen, panels 14a and l4g at least, are constructed from a plurality of rafters 90 on which a panel surface has been arranged.

Panels 14a-14d abut against one another and are arranged such as to span, and be supported by spandrels 12a and 12b across timbers 34a and 34b. Panels 14e l4g abut against one another and are arranged such as to span, and be supported by spandrels 12a and 12b across timbers 36a and fOb.

Reference is now made to Figures 2(a) and 2(b) which show floor cassette 26, which comprises floor 27 and rim 28, in this case rim panels 28a and 28b. Floor 27 is provided with two wall plates 82a, 82b, formed of a strap of timber which has an outer edge 84a, 84b respectively which is aligned with rim panels 28a, 28b respectively. Each wall plate 82a, 82b is further provided with an inner edge 86a, 86b from which rebates 88 have been machined such that they extend into the wall plate 82 towards outer edge 86. Each rebate 88 is provided with two opposing rebate side walls 87 and an abutting edge 89. In this case opposing rebate side walls 87 are tapered such that they are closer together as they reach the abutting edge 89 than they were at outer edge 86.

Abutting edge 89 is, in this case arouate.

In Figure 3, there is shown a portion of a panel 14, such as a roof panel 14a from Figure 1 arranged upside down. Panel 14 comprises a plurality of roof supports which in this case are rafters 90 arranged spaced apart from and in parallel to one another and to which panel surface 92 is affixed. In this case, five rafters 90 have been shown but it will be appreciated that any number of rafters may be used depending on the dimensions of the roof arrangement being constructed.

At leading edge 74, each rafter, or roof joist, 90 is provided with an angled surface 91 which a projection 94 projects therefrom. Each projection 94 has an oval cross section and in this case projections 94 were formed by machining each rafter end 91 prior to assembly of roof panel 14. Each projection has an end face 100, an abutting face 102 and parallel opposing side faces 104. The panel 14 is further provided with a facing plate 96. Facing plate 96 is a planar sheet of timber having a width which extends the width of leading edge 74 of panels 14, and a length which corresponds to the length of each rafter end surfaoe 91. The facing plate 96 is further provided with a plurality of voids 98 in this case oval shape void which shaped and are spaced apart to correspond to projections 94 such that when assembled, inner surface 96b of facing plate 96 abuts against rafter ends 91 and projections 94 project through voids 98 such that end face of projection 94 projects away from outer surface 96a of facing plate 96.

In Figures 4(a) and 4(b) there is shown a cross section of a roof system, and a corresponding detail of the cross section of the roof sysrem, which includes the floor cassette 26 described with reference to Figures 2 (a) and 2 (b) and roof panel 14 described with reference to Figure 3. As can be seen, when assembled, projections 94 are arranged such that they extend into corresponding rebates 88 so that abutting face 102 of projection 94 abucs against abutting surface 89 (not shown) Facing plate 96 acts to ensure that the roof panel 14 and floor cassette 26 are abutted against one another in such a way that no gaps or spaces are created which will require filling by a tradesman in order to ensure the roof is sealed.

To assemble the roof system 10 shown in Figure 4(a) and 4(b) the floor cassette 26 is tocated such that rims 28a and 28b correspond with and are supported upon walls 20. Although not illustrated, it will be appreoiated that rims 28c and 28d may similarly correspond with and be supported by walls 18. Roof panels 14 are arranged such that projections 94 of rafters 90 are arranged to correspond with a rebate 88 in floor cassette 26. Projections 94 are directed towards a side edge 84 of floor panel 27 of the floor cassette 26 such that the abutting face 102 of each projection 94 meets the corresponding abutting surface 89 of the rebate 88. Opposing rebate side wall 87 co-operate frictionally with opposing side faces 104 of projections 94. In this way, each rebate supports the weight of the corresponding rafter 90 at abutting surface 89 thus facilitating the distribution of the said weight across the structure of the floor cassette 26. Rafters 90 also meet and are secured together at apex 38 such that the roof panels 14 form a continuous roof surface.

In this way, roof supports, in this case rafters 90 formed as part of roof panels 14, can be located and supported simply by using a crane, thus removing the need for highly skilled workers at the location of building construction to locate and affix roof supports to the building structure. This saves considerable time and cost in the build and also increases safety.

As tapered rebates 88 receive oval projections 94, a friction grip is formed beoween the abutting components which therefore holds roof panel 14 in position relative to floor cassette 26 in a very secure fashion. Ihis arrangement ensures that minimal, if any, addition fixing is required to secure the roof panel to floor cassette 26. In addition, the weight of the roof supports 90 and roof panels 14 supported thereon ensure the roof supports are pressed outwards thus abutting securely with face plates 96.

Figure 5 shows a perspective view of a further embodiment of roof system 10 where a first floor cassette 26a is provided on building walls 18, 20 upon which a lower roof arrangement ha, including lower spandrels 12a and roof panels 14a, 14b, 14f, 14g is arranged in the manner detailed in relation to Figure 4 above. In this case, lower spandrels is formed of four timbers placed in a trapezoidal arrangement with a base timber 32b, two inclined timbers 34, 36b, and an upper timber 35b.

In this embodiment, a second floor cassette 26b is then provided on spandrel timbers 35, thus forming a ceiling. Upon second floor cassette 26b, an upper roof arrangement llb is constructed in the manner detailed in relation to Figure 4 above wherein each spandrel is formed of three timbers 32a, 34a and 36a placed in a triangular arrangement. Such a "piggy back" roof system 10 will have the weight of the roof system 10 distributed across floor cassettes 26a and 26b as well defining a useable attic space and providing further support in the roofing system 10.

The principal advantage of the present invention is that the floor cassette provides support to the roof supports which is spread across the extent of the floor cassette and therefore spread across the extent of the supporting walls. This reduces the pressure placed upon the side walls or end walls of a building thus minimising the potential for damage being oaused to the walls through supporting the weight of the roofing system.

A further advantage of present invention is that the roof supports can be simply arranged to co-operate with the roof cassette of the roofing system without the need for complex machinery or highly skifieci workers.

Yet a further advantage of the present invention is that once slotted into place, the roofing supports require minimal additional securing means to be used in affixing them to the floor cassette, this can minimise the cost and time associated with construction.

A yet further advantage of the present invention is that little is any void remains after the assembly of the roofing system. This improves the wind and water tiqhtness of the roof system during the construction phase and also results in a minimal cost being incurred in sealing the roof system upon completion.

It will be appreciated to those skilled in the art that various modifications may be made to the invention herein described without departing from the scope thereof. For example, whilst the rebates have been detailed as being tapered in cross section, it will be appreciated that they may have opposing sides which are parallel. In addition, the rebates and the corresponding projections have been detailed as having an arcuate abutting surface, however, the abutting surface may be, for example, triangular or square in cross section. The roof supports have been detailed as being roof joists or rafters, however it will be appreciated that the spandrels of the roofing system may be provided with projections which correspond to a rebate in the floor cassette and thus may be secured to a floor cassette in a manner as detailed herein.

Claims (1)

1. <claim-text>CLAIMS1. A floor cassette for use in a roof of a building, the floor cassette comprising a floor panel having a lower surface arranged for location upon a surface area on which a roof arrangement is to be provided; a substantially planar upper surface; a plurality of side edges and at least one wall plate wherein said wall plate is arranged on said upper surface such that an outer edge of said wall plate corresponds to a side edge of said floor panel and an inner edge of said wall plate comprises at least one rebate to provide an abutting surface to support at least a portion of a roof support.</claim-text> <claim-text>2. A floor cassette according to claim 1 wherein the floor cassette is provided with wall plates arranged at r opposing side edges of the floor panel.</claim-text> <claim-text>3. A floor cassette according to claim 1 or claim 2 wherein the lower surface of the floor cassette corresponds with an arrangement of an upper surface of walls of a building on which a roof has to be constructed.</claim-text> <claim-text>4. A floor cassette according to claim 1 or claim 2 wherein the lower surface of the floor cassette corresponds with an arrangement on an upper surface of a pair of spandrels of a lower roof arrangement on which an upper roof arrangement has to be constructed.</claim-text> <claim-text>5. A floor cassette according to any preceding claim wherein the floor cassette is formed of a solid timber rectangular annular frame upon which a piLanar timber sheet is secured.</claim-text> <claim-text>6. A floor cassette according to any preceding claim wherein each rebate has a tapered prcfiie.</claim-text> <claim-text>7. A floor cassette according to any one of claims 1 to 5 wherein each rebate has an abutting surface which is arcuate in profile.</claim-text> <claim-text>8. A floor cassette according to any preceding claim wherein the roof supports are roof joists or rafters, or spandrels.</claim-text> <claim-text>9. A roofing system for a building, the system comprising at least one floor cassette according to the any one of claims 1 to 7 and at least one roof support, the roof support including a first edge to locate against the abutting surface of the floor cassette whereupon the r floor cassette bears the weight of the roof support at the rebate.</claim-text> <claim-text>10. A roofing system according to claim 9 wherein the roof support is a spandrel.ii. A roofing system according to claim 10 wherein there is provided a pair of spandrels.12. A roofing system according to claim 9 wherein the roof support is a rafter.13. A roofing system according to claim 12 wherein there is provided a plurality of rafters.14. A method of constructing a roof of a building comprising the steps: (a) locating a floor cassette according to any one of claims 1 to 7 on a suitable surface area; (b) locating at least one roof support to correspond with a rebate of the floor cassette; (c) directing said roof support towards a side edge of a floor panel of the floor cassette such that the first edge of said roof support meets the abutting surface of the rebate; and (d) supporting said roof support weight at the abutting surface of the rebate and distributing said weight.15. A method according to claim 14 wherein the method includes the step of locating a roof support and corresponding floor cassette rebate at opposing sides of r a roof system.16. A method according to claim 14 or claim 15 wherein the method includes the step of locating a spandrel at opposing sides of the roof cassette such that they are supported by abutting against the wall plates of the floor cassette.17. A method according to any one of claims 14 to 16 wherein the method further includes the step of locating roof joists such that they are supported by abutting against the wall plates of the floor cassette.18. A method according to claim 16 or claim 17 wherein the method further includes the step of locating a second floor cassette on an upper surface of said spandrels.</claim-text>