GB2422383A

GB2422383A - Two part sliding halter for standing seam roof

Info

Publication number: GB2422383A
Application number: GB0424512A
Authority: GB
Inventors: Paul Andrew Gifford
Original assignee: AVENTIX DESIGN Ltd
Current assignee: AVENTIX DESIGN Ltd
Priority date: 2004-11-05
Filing date: 2004-11-05
Publication date: 2006-07-26
Also published as: GB0424512D0

Abstract

A roof comprises a plurality of halter brackets 9, each secured to a roof at a first end, the second end being slideably connecteable to a roofing sheet capture bead 16, over which the edge portions 3,4 of roofing sheets 1,2 may subsequently be seamed together. The capture bead is preferably substantially sold and includes shaped capture formations or recesses running axially therealong and into or onto which the halter bracket may be joined. The bead includes a central groove 17 which guides the bracket. The bracket may be made from a sheet of stainless steel. It can be made in two "L"-shaped parts 9a, 9b secured back to back or can be folded from a single sheet. At its second end the bracket may have flaps 12, 13 to engage with corresponding recesses 14,15 in the bead. The bracket may have stiffening ribs. In use the halter bracket allows sliding with the capture bead to accommodate thermal expansion etc, but prevents the bead sliding off the halter bracket during fitting.

Description

I

Improvements in and relating to standing seam roofing structures This invention relates to standing seam roofing structures of the type described in GB2167101 wherein generally "u" shaped roofing sheets have respective male and female edge portions which are partially pre-formed in manufacture and are finally formed during installation of adjacent such sheets on a roof support structure by being placed over lines of upstanding brackets, known as halter brackets, each having a head portion over which the respective male and female edge portions of the roofing sheets may be placed and then tightened or "seamed" together such that the joint thereby formed prevents the roofing sheet from being pulled off from the line of halter brackets, whilst still allowing axial movement along the line of the seam in order to accommodate thermal expansion.

A known problem with such prior art roofing structures is that they rely to a large extent on proper fixing of the various components, such as proper alignment of the halter brackets and proper seaming of the roofing sheet joint thereafter. If any of the brackets are poorly aligned or if the seamed joint is too tight, binding of the roofing sheets relative to the halter brackets can occur, causing at its least problematic sudden noise as tension between the roofing sheets and attendant halter brackets due to thermal expansion or contraction is suddenly released, and at its most problematic the roofing sheets may become torn, leading to failure of the roofing joint where this happens. On the other hand, failure to tighten the seamed joints sufficiently can lead to roofing sheets being pulled off the halter brackets in windy conditions, which can generate a vacuum effect over the entire roof, such that a common aim of designers and installers of such roofs is to ensure that high "pull-off' levels are maintained in order to prevent such catastrophic failure.

The foregoing problems are addressed in W098/531 58 (Hoogovens Aluminium Bausysteme Gmbh) by the expedient of making the halter bracket in two parts which are both slideable and rotatable with respect to each other.

This is achieved by the base portion of the halter bracket being made separate to the head portion and the intermediate web portion, the lower end of the latter being formed as a circular bead which is slideably received within a correspondingly shaped cylindrical groove within the base, adjacent edges of roofing sheets then being seamed tightly over the halter bracket head such that there is no longer any slideable movement therebetween. Apart from the obvious disadvantage with this system that it requires absolute precision of alignment of the bracket bases along the line of each seamed joint, where considerable thermal expansion or contraction occurs, and this may be in excess of 300mm over large roof structures, there is the danger of the upper part of one or more such halter brackets moving so much in the axial direction such that disengagement with the base occurs, again leading to catastrophic failure of the roofing structure. Another disadvantage with this system is that the load path from the roofing sheets through to the underlying structure onto which the halter brackets have been fixed is no longer controlled by the shape of the halter brackets, because the upper part is also rotatable about the axis of the cylindrical groove, allowing for unwanted radial movement about the major axis of the base of the halter bracket. This is an increasingly important consideration as a result of compliance with the Kyoto Agreement which has lead to ever increasing requirements to control energy loss, resulting in ever increasing thickness of the insulation barrier under the roofing sheet. In turn, this requires ever longer halter brackets to span the thickness of the insulation layer which, several years ago was typically only 70 to 100mm thick, but is shortly required to be between 250 to 300mm thick. This large increase can place considerable leverage loads on the halter brackets and their respective mountings, particularly if there is any binding of the halter head in the seamed joint. Leverage loads can be generated by thermal movement, wind pressure, snow loads, foot traffic and building operations, as well as through the use of roof access equipment. Where these loads are transmitted to a halter bracket by binding of the seamed joint thereabout, damage can be caused to the roofing sheet as well as to the underlying structure on which the halter bracket is fixed, including fasteners, which may be strained or even pulled out.

The present invention is derived in part from the realisation that there is a need for a standing seam roofing structure which does not depend upon the 1 5 skilfulness with which the seamed joints are made. The invention is also derived in part from the realisation that with increased and increasing leverage loads on halter brackets there is a need for them to be sufficiently rigid so as to control the load path from the roofing sheets through to the underlying structure, in particular preventing unwanted radial movement about the major axis of the base of the halter bracket, in contrast to the teaching of According to the invention there is provided a standing seam roofing structure comprising a plurality of roofing halter brackets, each halter bracket being adapted to be secured at a first end to a respective roof member and at a second, capture, end to slideably capture respective edge portions of adjacent roofing sheets, such adjacent edge portions being adapted to be seamed together to form a finished roofing joint, characterised in that the second end of each roofing halter is adapted to be slideably connectable to a roofing sheet capture bead, over which capture bead said edge portions of said roofing sheets may subsequently be seamed together to thereafter form a finished roofing joint.

Conveniently, the capture bead is substantially solid and includes shaped capture formations or recesses running axially therealong and into or onto which the capture end of a halter bracket may be slideably connected to both align the bracket with respect to the bead and prevent the bead from being pulled therefrom whilst allowing slideable movement with respect thereto.

With this arrangement, the male and female edge parts of adjacent roofing sheets may be seamed tightly onto the capture bead without the capture formations of the latter being deformed and because the bead itself may be a continuous length or at least relatively long compared to the width of the halter bracket, substantial thermal expansion or contraction of the roof structure may still be accommodated whilst maintaining high pull- off values between the roofing sheets and respective halter brackets.

A further significant advantage is that because the roofing structure of the invention does not rely upon sliding movement as between the seamed joint and the head portion of a conventional halter bracket, but instead between pre-formed parts which retain the same shape both before and after seaming of the roofing joint between adjacent roofing sheets, the problem of over or under tightening of the seamed joint is obviated. A further benefit flowing from this concept is that the halter bracket, usually made of aluminium so as to avoid galvanic reaction with the seamed joint of the aluminium roofing sheets, can instead be made of a different metal or may even be non-metallic in nature such as by being made of plastics, or a composite which includes plastics and metal.

Conveniently, the halter bracket of the invention may be made from sheet material, preferably stainless steel and most preferably made in two parts, both being substantially "L"-shaped, secured back to back to each other and including at their collective capture ends oppositely disposed capture flaps engageable in correspondingly shaped recesses in the capture bead, which bead may itself include a centrally disposed alignment groove acting as a guide for the extreme upper end of the halter bracket. With this arrangement, the halter bracket can be made from relatively strong sheet stainless steel which has another advantage over aluminium in having a higher thermal resistance and hence lower thermal conduction. The use of sheet stainless steel also affords the possibility of utilising monocoque types of construction including ribbing to increase stiffness and strength, and because of its inherent strength in comparison to aluminium the capture end of each bracket which is in contact with the capture bead can be relatively short i.e. shorter than the width of the whole bracket, thereby reducing the surface area physically in contact with the capture formation surfaces of the capture bead, thereby minimising both friction and thermal transfer.

The invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a sectional view of a prior art standing seam roofing structure showing the seamed together edges of a pair of adjacent roof panels supported by a halter bracket on a roof structure, Figure 2 shows a corresponding cross-section of a roof structure in accordance with the invention, Figure 3 is an exploded perspective view of the halter bracket used in the roofing structure of Figure 2, and Figure 4 is a perspective view of the capture bead used in the roofing structure of Figure 2.

Referring firstly to Figure 1, there is shown in section part of a conventional standing seam roofing structure comprising a pair of roofing sheets 1, 2 (only part of each of which is shown) having respective upstanding male 3 and female 4 edge portions, the latter overlapping the former to form a watertight joint supported on and by the head portion 5 of a standing seam halter bracket 6 having a base portion 7 which, in turn, is supported on a roof support structure 8 which may itself be an old primary roof requiring new secondary roofing over it, or a roofing bar for supporting a primary or "new build" roofing structure.

The structure thus far described requires as a final step in the forming of the female edge portion 4 of the roofing sheet 2 over the male edge portion 3 of the roofing sheet I the use of a metal deforming tool which "seams" the respective parts together to form thereafter a watertight joint. As will be appreciated, if the seamed joint grips the head portion 5 of the halter bracket 6 it will not allow the former to slide axially relative to the latter and, conversely, if the joint is made too loose there is a consequent danger that the roofing sheets 1, 2 may be pulled off the head portion 5 of the halter bracket 6 when subjected to suction caused by high winds when a pressure differential exists between the outside and inside of the roof.

As will be appreciated by those skilled in the art, the final step of seaming the joint between the male 3 and female 4 edges of the roofing panels 1 and 2 require great accuracy and even after a perfectly seamed joint is made any subsequent damage to any part of the structure in this region may cause snagging to occur which, as aforesaid, may not only lead to unwelcome noise as tension builds up and is then suddenly released, but to more serious consequences whereby buckling or even tearing of the roofing sheets 1, 2 may occur.

In Figures 2 to 4 an alternative arrangement in accordance with the invention is shown, where like parts to those shown in Figure 1 are numbered accordingly. However, in this arrangement the halter bracket shown generally at 9 is of generally two part configuration consisting of respective back to back L"-shaped halves 9a, 9b, each having respective foot portions 10, 11 by which the halter bracket 9 may be affixed to a roof support member 8, such as an existing roof or, for "new build", a roof support bar.

As can be seen more clearly with reference to Figure 3, at the upper end of the halter bracket 9 are oppositely disposed outwardly inclined capture flaps or louvres 12, 13 which are, in use, engageable via their leading edges 12a, 13a in correspondingly shaped capture recesses 14, 15 of an otherwise solid metal capture bead 16 (shown more clearly with reference to Figure 4) which capture bead 16, shaped externally to fit the internal profile of the end of the male edge 3 of the roofing sheet 1, also includes a centrally disposed groove 17 which extends axially therealong and acts as a guide for receiving the upper edge portions 18, 19 of the halter bracket halves 9a, 9b.

Each of the halter bracket halves 9a, 9b, includes strengthening ribbing which combine, when the respective halves 9a, 9b are joined together e.g. by spot welding, to impart structural rigidity to the halter bracket 9 which effectively then assumes a monocoque construction, with the inherent strength afforded thereby.

Since the halter bracket 9 can be made of e.g. stainless steel, it will be appreciated that due to the inherent strength of such material the overall width of the capture flaps or louvres 12, 13 relative to the major axis of the capture bead 16 can be reduced as compared with prior art halter brackets, thereby minimising surfaces between which friction may otherwise contribute to the potential for snagging.

In a refinement to this concept, the flaps or louvres 12, 13 may be staggered with respect to each other, there being a correspondingly shaped opening adjacent one such flap or louvre through which a corresponding flap of louvre of an adjacent halter bracket half may extend, the flaps or louvres being provided with interlocking ears allowing for respective halves 9a, 9b to be mechanically interlocked for use without requiring the use of e.g. spot welds to join the two halves together.

In a further refinement to the invention, the halter bracket 9 is made from a single strip of metal folded about its mid-point and then "clinched" together during final manufacture to form a weldless but nevertheless mechanically stable bracket in which respective projections from each side of the bracket extend into corresponding recesses in the other side of the bracket to thereafter be deformed in order to mechanically lock each half together as a single monocoque construction. I0

Claims

Claims 1. A standing seam roofing structure comprising a plurality of

roofing halter brackets, each halter bracket being adapted to be secured at a first end to a respective roof member and at a second, capture, end to slideably capture respective edge portions of adjacent roofing sheets, such adjacent edge portions being adapted to be seamed together to form a finished roofing joint, characterised in that the second end of each roofing halter is adapted to be slideably connectable to a roofing sheet capture bead, over which capture bead said edge portions of said roofing sheets may subsequently be seamed together to thereafter form a finished roofing joint.
2. A structure according to Claim I further characterised in that the capture bead is substantially solid and includes shaped capture formations or recesses running axially therealong and into or onto which the capture end of a halter bracket may be slideably connected to both align the bracket with respect to the bead and prevent the bead from being pulled therefrom whilst allowing slideable movement with respect thereto.
3. A structure according to any preceding claim further characterised in that the bead includes a centrally disposed alignment groove acting as a guide for the extreme upper end of the halter bracket.
4. A structure according to any preceding claim further characterised in that the halter bracket is made from sheet material, preferably stainless steel.
5. A structure according to Claim 4 further characterised in that the halter bracket is made in two parts, both being substantially "L"-shaped, secured back to back to each other.
6. A structure according to Claim 4 or Claim 5 further characterised in that the halter bracket is made from folded sheet material as a monocoque construction.
7. A structure according to any one of Claims 4 to 6 further characterised in that the halter bracket includes at its capture ends oppositely disposed capture flaps engageable in correspondingly shaped recesses in the capture bead.
8. A structure according to Claim 7 further characterised in that the capture flaps are symmetrical with respect to the major axis of the finished roofing joint.
9. A structure according to Claim 7 further characterised in that the capture flaps are disposed asymmetrically along respective sides of the halter bracket, to thereby increase pull out loading.
10. A structure according to any preceding claim further characterised in that the halter bracket includes ribbing to increase stiffness and strength.
11. A capture bead for use in a standing seam roofing structure according to any preceding claim further characterised in that the capture bead is substantially solid and includes shaped capture formations or recesses running axially therealong and into or onto which the capture end of a halter bracket may be slideably connected to both align the bracket with respect to the bead and prevent the bead from being pulled therefrom whilst allowing slideable movement with respect thereto.
12. A bead according to Claim 11 further characterised in including a centrally disposed alignment groove (17) acting as a guide for the upper end (18, 19) of the halter bracket (9, 90).

IL
13. A halter bracket for use in a standing seam roofing structure according to any one of Claims 1 to 10 further characterised in that the halter bracket is made from sheet material, preferably stainless steel.
14. A halter bracket according to Claim 13 further characterised in that it is made in two parts, both being substantially "L"-shaped, secured back to back to each other.
15. A halter bracket according to Claim 13 further characterised in that it is made from a single sheet in a substantially monocoque type of construction.
16. A halter bracket according to any one of Claims 13 to 15 further characterised in including at its collective capture end oppositely disposed capture flaps (12, 13) engageable in correspondingly shaped recesses in a capture bead.
17. A halter bracket according to any one of Claims 13 to 16 further characterised in that it includes ribbing to increase stiffness and strength.
18. A standing seam roofing structure substantially as described with reference to Figure 2.
19. A halter bracket for a standing seam roofing structure substantially as described with reference to Figure 3.
20. A capture bead for a standing seam roofing structure substantially as described with reference to Figure 4.