Background of the Invention Hollow extruded aluminium, PVC or steel door and window systems have been in use for many years as a durable relatively low cost alternative to wooden equivalents.

However, while there are a number of high quality products which are relatively appealing in an aesthetic sense, there is a general perception amongst the public that windows and doors of this kind often look"cheap"because of their small frame cross section sizes compared to those having profiled timber frames.

The problem is exacerbated where the window or door is installed in a dwelling clad with plank siding or fibre cement sheeting and the like. The lack of thickness in the wall gives more interior room space but it may be difficult to recess the frame into the wall to provide an aesthetically pleasing surround or reveal. Brick clad wall constructions on the other hand are particularly suited to the formation of deep inset external reveals due to their wall thickness. Deep inset external reveals provide a substantial visual frame around the window or door opening which is a factor in the perceived aesthetic superiority of masonry dwellings over plank or sheet clad dwellings.

While special preformed surround elements may be used in clad dwellings, such componentry is usually expensive and/or labour intensive to install. Furthermore the preformed surrounds or trim units are commonly installed such that they simply abut the frame like picture frames fastened to the cladding. Installation of such trim units requires that an appropriate sealant be meticulously applied at the junction between the

frame and the surround to ensure an adequate weather seal. These factors add to the time and cost of construction.

Throughout the specification the term"surround"will be used herein to refer to any building facing structure around a wall opening such as a door or window. Typically the surround will include within its scope an internal or external reveal or surround for the sill, jamb and head elements of the window or door frame. However the term "surround"as used herein excludes any panelling or structural members of the wall itself.

With any window or door structure, it is important for the structural sealing and aesthetic purposes that the window or door frame elements be neatly and accurately connected with the opening surround structure. However achieving these requirements tends to increase the time and skill level required for installation.

It is an object of the present invention to overcome or ameliorate at least some of the disadvantages of the prior art or at least offer a useful alternative thereto.

Disclosure of the Invention Accordingly, the present invention provides a frame assembly for use in a window or door frame surrounding an opening in a wall, the assembly including: a longitudinally extending frame element adapted to retain a window or door assembly, the frame element being structurally but releasably connected to a longitudinally extending surround element; the surround element having a fixing portion for receiving fixing elements such that the surround element can be mounted to a structural member beside the opening, wherein said frame element is detachable from said surround element after installation in said wall opening.

Preferably, the surround is adapted to be mounted to the structural member from

the exterior side of the wall.

By fixing the window or door frame to the surround in the factory, and configuring the surround for direct attachment to a wall stud, the weather seal between the frame and the surround can be formed in the factory. This provides a high integrity seal and avoids the labour costs of applying sealant on site.

The frame assembly can be used in the sill, head and jambs of a window or door frame, so that an entire factory sealed frame can be installed as a single structure into the wall opening. Furthermore adapting the external surround such that it can be secured from the outside of the wall is more time and cost efficient than securing from the interior.

Preferably the frame element is connected to the surround such that it can be detached from the surround and then re-attached to the surround from the interior of the wall. In one form, the frame element is connected to the surround via a longitudinally extending mounting fin adapted for receiving fixing elements which can be removed to detach the frame element from the reveal or surround without removing the reveal or surround from the structural member.

It will be appreciated that this form of the invention allows a window to be conveniently removed and replaced from inside the wall. Furthermore it avoids breaking the weather seal between the surround and the wall membrane.

In some forms, the surround defines a longitudinal channel to retain the longitudinal edge of a building panel forming part of the wall. Preferably the channel is configured to retain the longitudinal edge by means of a close or sliding fit. In further preferred embodiments, the interior wall of the channel extends beyond the exterior wall to provide the mounting fin.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which : Figure 1 is a cross sectional view of the sill portion of a window opening and first embodiment frame assembly according to the present invention; Figure 2 is a cross sectional view of the frame assembly of figure 1 in isolation; Figure 3 is a cross sectional view of a head or jamb portion of a window incorporating a first embodiment frame assembly according to the present invention; Figure 4 is a cross sectional view of the frame assembly of figure 3 in isolation; Figure 5 is a cross sectional view of a head portion of a window opening and second embodiment frame assembly ; Figure 6 is a cross sectional view of a jamb portion of a window opening and second embodiment frame assembly; Figure 7 is a cross sectional view of a sill portion of a window opening and second embodiment frame assembly; Figure 8 is a cross sectional view of a head portion of a window opening and third embodiment frame assembly; Figure 9 is a cross sectional view of a jamb portion of a window opening and third embodiment frame assembly; and Figure 10 is a cross sectional view of a sill portion of a window opening and third embodiment frame assembly.

Referring to figures 1 and 2 the frame assembly 1 forms the sill of a window opening. The longitudinally extending frame element 2 holds the fixed and sliding sash of a window (not shown). The frame element 2 is structurally connected to a longitudinally extending surround 3 via a series of removable fixing elements 4. These

can comprise any suitable releasable fastener and are illustrated in the form of screws.

The frame and surround may be fixed together at the factory where a bead of sealant can be applied at suitable points such as those shown at 5 so that a weather seal between the surround and window frame exists prior to installation.

The surround 3 extends generally downwardly and outwardly to form a sill reveal.

At the distal end of the reveal two longitudinally extending fins 6 and 7 form a channel for receiving a base sheet building panel 8 in a close or sliding fit. The frame assembly 1 is slid over the edge of the panel 8 until the support leg 9 abuts the sill trimmer 10. The interior fin 7 extends beyond the exterior fin 6 to allow the panel 8 and frame assembly 1 to be fixed to the sill trimmer 10 with fixing elements 11.

The surround 3 has a corner bead and screeding edge 12 to support a textured exterior coating 13. On the surround 3, the coating 13 extends from the drainage slot 14 to the corner bead and screeding edge 12. From the screeding edge the texture coating 13 covers the base sheet panel 8 and the heads of the fixing elements 11.

On the interior side of the wall plasterboard is simply butted up against the frame element 2 and sill trimmer 10 to cover the 25 to 30mm concrete render 16. To complete the installation, an architrave 17 is fixed around the junction between the plasterboard 15 and the frame element 2.

Referring to figures 3 and 4, it can be seen that the jamb and head sections of the window are installed in a similar manner. The frame assembly 1 is formed by connecting the frame 2 and surround 3 with a series of fixing elements 4 at the factory.

A bead of sealant 5 is also applied at the factory to provide a weather seal between the frame 2 and the surround 3. The base sheet 8 of the wall is slid into the channel formed by fins 6 and 7. The frame assembly 1 and base sheet 8 are then secured to the wall stud 10 with fixing element 11.

As with the sill section, the texture coating 13 is applied to the surround out to the corner bead and screeding edge 12 and then over the base sheet building panel 8. At the interior side of the wall, plasterboard 15 abuts the edge of the frame 2 and the wall stud 10. Architrave 17 is fixed around the interior periphery of the frame to complete the installation.

Referring next to figures 5 to 7 there is shown an alternative second embodiment of the invention that includes an external surround element and internal reveal element.

Where possible like references have been used to denote corresponding features.

As can be seen, the frame assembly 1 includes an external surround element shown in each figure as item 3 which is mounted to the wall frame member 10 with fixing element 11 that passes through mounting fin 7. The frame element 2 which holds the window sashes is then structurally but releasably connected with the surround element 3 by means of a series of first fixing elements 4. Again, the two components may be factory assembled with sealant applied as required.

With this second embodiment a third frame component is also provided in the form of an internal reveal element 20 which in the embodiment illustrated is mounted to the external surround section 3 via second releasable fixing elements 4'. In this manner, the frame element 2 can be removed from the assembly after installation in the window opening by disconnection from the surround element only. However, in alternative forms, similar to that illustrated in figures 8 to 10, the frame element 2 may be structurally connected with the internal reveal element 20. The internal reveal element may in turn be directly structurally mounted to the wall frame 10 by additional fixing elements 21.

Connected with and forming part of the internal reveal element 20 is an architrave or cover strip 22 which is preferably designed to clip on to the reveal element and which

defines at least part of the internal reveal surface and hides the releasable fixing elements 4 and 4'.

Finally, figures 8 to 10 illustrate a third embodiment of the invention where again like reference numerals will be used to denote corresponding features.

The primary difference with this third embodiment is that the surround is in the form of another internal reveal element 25. This reveal element is mounted with the wall member 10 by means again of a mounting fin 7 which is secured to an inner side of the wall member 10.

As in the previous embodiments a frame element 2 is structurally but releasably connected with the surround or reveal element 25 via connecting flanges 26 and 27. In this embodiment the reveal surface is defined primarily by the reveal element and only a small clip on cover 28 is provided to conceal the releasable mounting means. The operation of the clip on cover is shown as part of figure 10. The external surround element can be of any suitable structure and may or may not structurally interconnect with the frame element 2 and/or the reveal 25.

It will be appreciated by those skilled in the art that the frame assembly formed according to the present invention allows for rapid installation of an optionally fully sealed window or door frame assembly into walls. Adapting the external surround to be fitted from the outside allows the frame assembly to be face fixed to the exterior of the timber or steel framing or other wall structure. Furthermore, the window can be removed and replaced from the inside without disturbing the outer reveal and its sealed connection to the wall membrane. Similar comments apply in respect of those embodiments including an integrally connected internal reveal section.

Accordingly preferred forms of the present invention effectively avoid the need for the materials and labour associated with shaped factory fitted wooden sections stapled to

the window frame, fitting flashing on-site, forming base sheet reveal sections on-site, installing polyfoam, installing a separate screeding and edge protector angle, meticulously applying beads of sealant, and the installation of sill packing.

A factory sealed frame assembly according to the invention has significant cost advantages while providing a wall opening surround structure that retains the aesthetic appeal of a masonry or full timber structure. Furthermore, it is completely compatible with most clad dwelling structures as well as brick.

The invention has been described herein by way of example only. Skilled workers in this field will readily recognise many variations and modifications which do not depart from the spirit and scope of the broad inventive concept.