This invention relates to door frame assemblies, and to a method of installing a door.

Traditionally, when building partition walls and particularly when installing a door in such a wall, a dry wall contractor would form an orifice in a plasterboard partition. A timber or metal doorset comprising a frame and a door would then be installed in the orifice. The dry wall contractor would then return, install an edge trim such as a rebate trim, around the installed frame, and would plaster the wall.

However, it is common for the orifice to be of the incorrect size, shape or location, or lacking in plumbness, be it due to errors in design information, lack of coordination between the different parties or simple poor workmanship. Furthermore, this system requires two visits by the dry wall contractor - one to install the partition with the orifice, and the second to plaster the wall. This is inefficient.

According to a first aspect of the invention, there is provided a door frame assembly, comprising a support frame suitable for fitment with a door and integral support members extending away from the frame, the support members and the door frame being arranged so that the assembly can be supported by a floor and by the ends of the support members distal from the frame, in which the support frame comprises two upright members which define the sides of the support frame, spaced apart by a distance determined by the width of the door to be fitted, in which each upright member has a generally C-shaped cross section and comprises a base part and a pair of opposing spaced apart side flanges that extend away from the base part, the base of each member facing the base of the opposing member with the side flanges of each of the members extending away from the door, and further in which the upper and lower ends of each upright member form at least a part of the support members.

By providing uprights of a support frame with a C-shape cross section provides several advantages during installation of a door and a surrounding wall. Firstly it is easy to secure the uprights to a door frame by fixing through the base into the door frame, perhaps using self tapping screws. Having an open C-shaped cross section gives clear access compared with the use of box section members. It also means that the sides that extend away from the door are suitable for fastening panels to such as plasterboard. Thus, the frame can be erected and dry wall panelling secured to it using any standard dry wall fastening technique. Because the flanges are part of the door support assembly and the panels overlap these flanges the resulting structure can provide excellent levels of protection against fire, in some cases meeting and exceeding British Standards test such as BS5234-2 and DD-171. The open c-shape allows, for instance, an insert strip of material, perhaps panel material, to be fixed to the base of the upright between the flanges which provides additional protection against fire at the critical joint between the panels and the door frame assembly. This also helps prevent sound passing through the completed wall as may cover the points where the fasteners penetrate the flanges.

The use of a C-section defining an open channel gives total flexibility to the contractor erecting a wall using the door frame assembly in terms of achieving desired levels of fire, acoustic, insulation and/or thermal insulation. If an upright member such as a box section was used it would need to be insulated internally to meet the same standards, which is hard to achieve and does not offer the same level of flexibility- with the system of the invention the same door frame assembly can be incorporated into virtually any kind of walling system to achieve a wide range of different standards. With a box section the inside of the box would need to be somehow insulated to the right level and a different box section may be needed for each installation depending on the desired properties of the completed wall.

The applicant has appreciated that it is not possible to use standard dry wall component upright members, which are traditionally used to construct dry walls, as they lack the strength needed to support a door before the wall is erected. These members typically are steel with a gauge of between 0.5 and 0.9mm and being of I or C section. As such they would easily deform giving a mis-shaped door opening. If a door is then fitted to the opening there may be unwanted gaps which would cause a problem in the event of a fire.

Therefore, the upright members preferably comprise members which are sufficiently rigid to support a door and door frame prior to construction of a wall around the support frame and of thicker gauge than standard dry walling upright members. This can be achieved using a C-shaped member for each upright of steel material and with side flanges having a gauge of between 1.5 and 1.7, and preferably around 1.6mm.

The gauge of the base part may be the same as that of the side flanges. It may comprise a single thickness (layer) of material, so that the upright forms a simple channel. This has additional advantages for acoustic rating of any resulting wall, as well as the insulating properties of the wall because the flat base can sit flush against a door frame fitted to it without forming a void which would form a path for acoustic energy through the support frame. Panels can be fixed onto the flanges and also inside the flanges against the base as required. For instance, on both sides of the wall the panels may be secured on the outside of the flanges. Alternatively, on one side the panel may be secured to the outside of the flange

A standard dry wall upright member would use a thinner gauge as it is not generally required to offer much rigidity until it is integrated the finished wall. The applicant has appreciated that the use of the proposed gauge provides the required strength whilst still being easy to penetrate with self tapping screws of nails during construction of a surrounding dry wall. Depending on the application, it may mean the uprights do not need any additional reinforcement. Hence the uprights may consist solely of C- shaped members (plus any additional fasteners or fixings they may carry) .

The ends of the support members may provide substantially the whole of a respective support member, although they may be provided with respective adjustable feet for fine tuning of their length. Generally the length of the upright members should be chosen to be substantially equal to the spacing between the floor and a ceiling track to which the support frame is fitted minus a length to accommodate and feet.

The base part of each upright member may have a width equal to the required spacing between the panels when the wall is constructed. The base section may have a width that is less than the thickness of a door frame which is to be installed in the opening between the upright members.

Each upright section may comprise a continuous pressed or folded metal component, the side flanges being set at right angles to the base part after pressing from a flat strip of material. The part may be formed by folding a flat strip in any known manner. If required, each upright member may comprise two or more such components connected together end on end, perhaps with some overlap. This enables the support members to be separate to the uprights, albeit that they should also have generally the same c-shaped cross section.

The upright members may be connected by upper and lower horizontal cross members, which may be of the same profile as the upright members, Thus the whole support frame may be constructed from the same elongate members cut or preformed at the desired lengths.

Thus, a self-supporting door frame assembly is provided, that does not require a door or a door frame to be fitted in order to be supported. The support members may be arranged so as to provide support from a ceiling above the door frame assembly, so that, on installation of the door frame assembly, no supporting wall or partition may be required or indeed provided. The support frame can be of any height relative to the ceiling, as it is not required that the support frame extends to the ceiling itself.

The assembly may be provided with lower support members, which depend from the support frame in an opposing direction to the support members. Typically, the ends of the lower support members distal from the support frame would engage the floor. Each distal end may comprise an adjustable foot, to allow adjustment of the length of the respective lower support member, typically to allow for uneven flooring and also to bias the support members against the ceiling. The use of lower support members allows the assembly to be installed with the support frame at any convenient height positioned between floor and ceiling. As mentioned these lower support members may comprise, at least in part, part of the upright members. The support members will typically be elongate members, and may be integral with the support frame, of C-shaped section.

In addition to the upright member the support frame will typically comprise a plurality of further elongate members which together define an orifice for a door; the support members may comprise extensions of the elongate members of the support frame. Indeed, each support member may form a single piece with an elongate member of the support frame.

The assembly may be arranged such that it can be positioned in a building, before a door is attached, with a door being subsequently installed in the frame. In this position it may be sufficiently rigid as to be self supporting, albeit also that it can be affixed at the top and bottom to a ceiling or floor as required. As such, the support frame may be arranged to receive a door directly. Alternatively the support frame may be arranged to support a door set comprising a door frame supporting a door, in which the support frame is arranged to support the door frame of the door set. Typically the door frame assembly would extend from floor to ceiling, with the distal ends of the support members engaging the ceiling.

The frame is of a convenient size to be handled, as it is not much greater in width (width being the horizontal direction in the plane of the door orifice) than the door orifice which it forms - for example, the frame assembly may be at most 5% or 10% wider than the door orifice.

The assembly may further comprise a head track, which can be fixed to a ceiling, and which the distal ends of the support members may be arranged to engage, for example by being of an appropriate size to fit within the head track. Alternatively, the distal ends may be arranged to as to directly engage a portion of the ceiling, such as a concrete ceiling soffit. The distal ends of the support members may be provided with engagement means, such as angle brackets, by means of which the distal ends engage the head track or other ceiling portion.

The assembly may further comprise a base track which may be secured to the floor.

The head track, and/or the base track may comprise tracks with a C or U shaped cross section into which the uprights, or the support members, engage. These tracks may comprise part of a proprietary dry wall fixing system as is known in the art, and the dimensions of the upright members may be chosen so as to be compatible with these tracks. In one arrangement the uprights may be of similar dimensions to any upright members that form part of the standard system differeing only in that they are of a heavier gauge to enable them to give the required rigidity.

The assembly may be provided with a safety rail, which can be removably installed in the frame in place of a door, to prevent inadvertent falls through the orifice that the door would otherwise block. Such a safety rail may be positioned at approximate average waist height, to prevent human falls, or at a low height - a so-called "kicker rail" to prevent objects being inadvertently pushed through the orifice. Typically, the safety rail would be mountable horizontally in the frame.

Where the assembly includes a door set fixed between the uprights, the width of the base of the upright members may be less than the thickness of the door frame of the door set so that an end face of a panel subsequently fitted to a flange of the upper right member can abut against a protruding edge of the door frame. This again helps with fire safety. If desired a strip of sealing material may be located in the gap between the end face of the panel and the protruding part of the door frame. An intumescent strip could be used where a good fire rating is desired. This will then sit over the join between the C-section and the door frame, as well as sealing the end face of the wall panels. The strip is preferably resilient to accommodate any non-linearity of the door frame or panel end face.

According to a second aspect of the invention, there is provided a method of installing a door, comprising fixing a door frame assembly according to the first aspect of the invention between a floor and a ceiling, and installing a door in the support frame.

Typically, the step of installing the door will comprise the installation of a door set, comprising a door frame supporting the door, in the support frame. In the preferred embodiment, once the door set is installed, the support frame will support the door frame, which will in turn support the door. This allows any commonly available door set to be used with the door frame assembly. The door frame of the doorset may be connected directly to the base of the c-shaped upright members.

The door may be installed after the assembly is fixed; this is typically the case where a timber door is used. Alternatively, the door may be installed in the door frame assembly before the assembly is fixed; this is typically the case where a metal door is used.

The method may comprise the step of installing a head track on the ceiling before the door frame assembly is fixed, and then, as part of the step of fixing the door frame assembly, fixing the door frame assembly to the head track. The installation of a head track is common when installing dry walls, and so this advantageously makes use of a pre- existing component. Typically, the distal ends of the support members would be engaged with the head track, possibly by use of an engagement means such as an angle bracket.

The method may comprise the step of building a wall around the door frame assembly after it has been fixed. The wall may be a partition wall, or alternatively any other type of wall, such as a glass wall, a blockwork wall or external cladding. The step of building the wall may comprise the steps of constructing a partition wall around the door frame assembly. In the preferred embodiment, the method then includes plastering around the wall. An edge trim, such as a rebate trim, may be installed around the door frame assembly.

The step of building a wall may comprise abutting wall panels, such as drylining panels, against either the outside faces of the side flanges of the upright members or the inside faces (or perhaps onto both faces) and securing the panels in place by driving (by screwing, hammering or otherwise) fasteners partially through the dry wall and the flange.

The method may further comprise adding a length of panel material or some other fire resistant material or sound insulating material or thermally insulating material up against the base of the channel between the flanges. This material is preferably a section of the same panel material that is secured to the flanges.

The fact that the wall need only be built after the door frame assembly has been installed means the dry wall contractor can complete the wall construction and the plastering in a single visit. Furthermore, because the wall is built around the door frame assembly, the wall can be built much more accurately to the correct dimensions. Because the uprights provide a direct connection to the dywall panels the resulting assembly is both strong and also can easily comply with any fire regulations that the drywall must meet. This is especially true where the end faces of any panels used abut an edge of the doorframe that protrudes beyond the edge of the base of the upright members. There is no need to affix a separate drywall upright to the frame which can lead to an unwanted, and uneven, gap between the edge of the door frame and the panels.

The door may be installed before or after the wall is built; after would be the norm for timber doors. Especially where the door is installed in the door frame assembly after the wall is built, and especially where the door is to be a riser door, the method may include the step of installing a safety rail across the support frame. Typically the safety rail would be removed before the door is installed in the support frame, typically after the wall has been built. The safety rail may be positioned to stop people falling through the orifice provided by the support frame without a door, or may be provided at a lower level in order to prevent objects inadvertently being pushed through the door (a so-called kicker rail) .

There now follows, by way of example only, embodiments of the present invention described with reference to the accompanying drawings, in which:

Figure 1 shows a perspective view of the door frame assembly of a first embodiment of the invention, with a door installed,

Figure 2 shows a cross section taken horizontally through the frame of the assembly of Figure 1 ;

Figure 3 shows a perspective view of the engagement of the support members by the head track of the assembly of Figure 1 ; Figure 4 shows a perspective view of the door frame assembly of a second embodiment of the invention, without a door installed;

Figure 5 shows the same view as Figure 4, with a door installed;

Figure 6 shows a cross section taken horizontally through the frame of the assembly of Figure 4;

Figure 7 shows a perspective view of the adjustable feet of the door frame assembly of Figure 4; and

Figure 8 is a cross section taken horizontally through the door frame assembly of Figure 1 when built up to form part of a drylined wall of alternative construction.

Figures 1 to 3 show a first embodiment of the present invention, for use with metal doors. The door frame assembly comprises a support frame 1 , with two elongate support members 2 extending vertically upwards from the support frame 1. Two further members (not shown) may extend downwards from the support frame. The support frame 1 comprises four members; two vertically extending upright members 3 and two horizontal members 4, 5.

The members 3, 4, 5 define a portal through which access can be controlled by the use of a door 6b blocking the portal. The support members 2 extend vertically as extensions of the vertical members 3- as shown they are integral to the upright members so the ends of the upright members may be considered to form part of the support members; the support members 2 and the vertical members 3 form two continuous vertical members. Adjustable feet 7 control the height of the frame above a floor. The support frame 1 and the support members 2 would typically be made of steel. Each upright member and support member are of C-shaped cross section along their length. The uprights are steel members, pressed or folded from a flat sheet with a gauge of 1.6mm. If a lighter material such as aluminium is used a heavier gauge may be provided to give the required stiffness. This gauge gives the required strength for the frame whilst still enabling the flanges to be easily penetrated by fasteners when building the support frame into a wall.

The functioning of this assembly is best described by considering the method by which it is installed. Firstly, a head track 8 is attached to a ceiling above where the door is to be positioned, as part of the preparation process for a partition wall being installed. The head track comprises a C-shaped track which forms part of a proprietary dry wall component system. A door set 6 is installed into the support frame 1 of the door frame assembly. The door set comprises a door frame 6a and a door 6b. Any suitable door set commonly available can be used.

The door frame assembly, together with the door set 6 is then installed such that the ends of the upright members of the support frame 1 which define the upper support members in this embodiment (hereafter the distal ends 9) are retained in the head track 8. The width of the base part of the upright members is less than the internal width of the head track so it is snugly located. The adjustable feet are adjusted such that the support frame 1 is at the correct height, and that the support members are securely retained in the head track 8 as shown in Figure 3.

In this Figure, an angle bracket 12 is secured to the support member 2 by means of nut and bolt 13, and to the head track 8 by means of a screw 14.

Some flexibility in the position of the angle bracket relative to the head track 8 and the support member 2, and hence of those two members in relation to each other, is provided by the nut and bolt 13 and the screw 14 engaging the angle bracket 12 by means of slots 12a, 12b.

This work would typically be carried out by a joinery contractor or other door installer.

Accordingly, the door frame assembly is now self-supporting, due to the rigidity of the upright members, and will have been placed in the correct position by the joinery contractor. By selecting the appropriate lengths of the support members 2 and the vertical members 3, it is possible to correctly position the frame merely by ensuring that the distal ends 9 are correctly retained in the head track by adjustment of the adjustable feet, assuming that the height of the ceiling is known. There is therefore less possibility of measurement error.

The dry wall contractor now visits in order to install a plasterboard partition 10 or wall, as shown in Figure 2. The boards are fastened directly to the side flanges of the uprights by driving fasteners through the board and flanges. This gives a neat overlapping finish, and importantly enables a high fire safety rating to be achieved. A rebate trim 11 , being an example of an edge trim, is fitted, and the partition is plastered. Thus, it can be seen that the dry wall contractor can complete both the erection of the partition and the plastering in a single visit and using only standard dry wall construction tools and techniques. Because the wall is erected around the door, the orifice for the door in the partition wall is more likely to be in the correct place, and be of the correct size. It will also be obvious very quickly if the wall is not plumb with respect to the frame, rather than only becoming obvious after the dry wall contractor has left and the joinery contractor has started installing the door. A second embodiment of the invention, for use with timber doors, is shown in Figures 4 to 7 of the accompanying drawings. The same reference numerals have been used as in the first embodiment for corresponding integers, with the reference numerals raised by 20.

Figure 7 of the accompanying drawings shown in greater detail the adjustable feet 27, which could be used with either embodiment of the invention. The feet 27 themselves comprise a threaded member 37, which is supported relative to an angle bracket 36 which is itself fixed to the edge of the frame 21. A disc-shaped foot portion 39 is provided at the bottom of the threaded member 37. The threaded member 37 is held captive between two nuts 38 (only the top nut 38 being visible in Figure 7) on either side of the angle bracket 36, such that rotation of the foot 27 drives the foot vertically relative to the angle bracket 36 and so the frame.

Given the evident similarity between the two embodiments, it is merely necessary to describe how this embodiment functions during installation.

Initially, as shown in Figure 5 of the drawings, the joinery contractor will install the door frame assembly between the head track 28 and the floor without a door 26 being fitted. As in the previous embodiment, the adjustable feet 27 can be used to raise the door frame assembly such that the distal ends 29 of the support members 22 engage the head track 28, where they can be secured using an angle bracket as described with reference to the first embodiment.

The joinery contractor also installs a removable safety rail 35 across the frame, as otherwise an open portal is provided that could be fallen through. Positioned as shown, this safety rail 35 will prevent people falling through the open orifice; alternatively, or additionally, a kicker rail may also be provided, approximately 30 centimetres off the bottom of the support frame 1 , in order to prevent objects inadvertently being pushed through the orifice.

As previously, the door frame assembly is now self supporting. The relatively heavy gauge of the upright members, when compared with standard dry wall construction components, provides the required rigidity to the door frame apparatus.

The dry wall contractor then builds a plasterboard partition wall 30 around the frame assembly, as is shown in Figure 6 of the accompanying drawings. An edge trim, such as the rebate trim 31 shown, is installed, and the dry wall contractor plasters the wall 30. As such, both tasks can be completed in a single visit, and all of the advantages of the previous embodiment are also enjoyed.

The joinery contractor then returns, removes the safety rail 35 and installs a timber door set 26. This is secured directly to the base of the u- shaped upright members. This door set comprises a door frame 26a off which is hung a door 26b. Any commonly available suitable door set can be used. This operation leaves the door frame assembly in the state shown in Figure 5. The door has been installed accurately in the correct position, with a minimum of inconvenience to all involved.

A benefit of the use of the C-section upright members is that it is simple to ensure that a wall can be constructed in accordance with desired fire, acoustic and thermal requirements provided that the specification of the rest of the materials used to construct the wall are known. As shown in Figure 8 a strip of wall panel 20 may be provided which runs along the whole length of the upright and the support members and abuts the face of the base of the upright between the flanges. This will then lie underneath the region at which the end face of the outer wall panels abuts the protruding portion of door frame, which occurs because the door frame thickness is greater than the width of the base of the upright members. The inner strip of material helps prevent sound leaking through the wall, and also helps fire breaking through if it is of a fire resistant material, which would be the case if the wall panels from which the material was made were fire resistant. An optional intumescent strip 21 ,22 may be provided between the end face of the panels and the door frame, and as shown a double layer of panel enables a neat rebated finish to be achieved.