GB2404202A - Multi - chambered cavity closer - Google Patents

Abstract

A cavity closer has a plurality of chambers 7,9,11,13,15 to reduce thermal conductivity. Where the overlying jamb of a window or door frame is significantly inset with respect to the cavity closer, chambers may be provided with insulation, e.g. injected insulating foam.

Description

Improvements in or Relating to Cavity Closers This invention relates to

cavity closers for closing the cavity between inner and outer leaves of a cavity wall constructed of brickwork or Clockwork around reveal openings for windows and doors. More particularly, the invention relates to cavity closer systems providing improved thermal performance for various configurations of window and door system.

Generally, cavity closers have a body member which is built- in between the inner and outer leaves of a cavity wall during construction of the wall and have at least one flange member which rests against the reveal of one of the leaves.

The openings formed in cavity wall leaves for providing the location of windows and doors may either be identical in size and aligned so that the adjacent reveals lie in the same plane ( referred to herein as co-planar revealsH) or else opposite pairs of reveals, normally just the vertical reveals, of the outer aperture are slightly closer together that the corresponding inner reveals to form what is known as a "check reveal'". Window or door frames fitted to a check reveal must be fitted from the inside but are desirable because of the resultant high thermal resistance along the cavity closer pathway.

Cavity closers for co-planar reveals are normally provided with opposed flanges for contacting opposed inner and outer reveals whereas closers for check reveals have a flange for contacting the inner reveal and a vertical end section to provide an abutment with the vertical surface of the outer leaf.

Heat may flow from the interior of a building by conduction and convection via the shortest available path through the cavity closer to the exterior and it is desirable that such losses should be reduced to within prescribed limits.

Further, the thermal losses of a cavity closer in situ depends in part upon the location ( or "inset") of the jamb and sill of a fitted window or door with respect to the cavity closer. Different window configurations, that is those fitted into a co-planar reveal with different insets, or into a check reveal, all produce different degrees of resistance in the thermal pathway.

In the case of a co-planar reveal, for example, the jambs and sill of a frame are generally inset with respect to the cavity by predetermined distances, the inset being the horizontal distance by which the inner edge of the jamb or sill overlies the cavity. The fitting of a frame to a check reveal adds a further arrangement which affects the thermal resistance of the closer.

An object of the invention is to provide a cavity closer having a higher intrinsic thermal resistance compared with conventional closers, but which may be adapted by the provision of incrementally adjustable insulation for system configurations of variable thermal resistance.

In one aspect, this invention consists in a cavity closer system having, in use, opposed upright side closer elements and a horizontal lower closer element adapted for use with a co-planar reveal or check reveal, the closer elements each having a bridge member which in use bridges the cavity, and a body member which in use extends into the cavity, the body member being formed with plurality of adjacent, hollow chambers extending perpendicularly from the bridge member to form a series of insulating compartments each forming a thermal barrier to heat flow across the cavity.

Preferably the cavity closer elements have a central compartment disposed between inner and outer compartments.

The inner and outer compartments may each be vertically divided into separate sub-compartments providing five intrinsically insulating contiguous chambers.

To facilitate fitting of a particular configuration, such as a window system, abutment means are provided along the external side of a bridge member of the vertical closer elements for locating the edges of the window frame at a required inset position with respect to the reveal opening.

The closer element which in use lies beneath the sill does not require means for locating the sill at a required inset since the sill inset position is determined by the inset position of the window frames to which it is fixed.

The heat loss through the cavity closer is significantly affected by the inset position of the window or door relative to the cavity closer and the thermal resistance of each such configuration.

As will be more fully described below, in various configurations, cavity closer elements fabricated in accordance with this invention have sufficient intrinsic thermal resistance to meet current thermal resistance standards without need for additional thermal insulation.

However for configurations with minimal inset, one or more of the compartments are selectively provided with insulation to meet prescribed thermal loss requirements under Part L of the relevant Building Regulations currently in force. Generally, as will be further described, the need for and degree of selective insulation enhancement may be determined from the inset configuration.

In a further aspect this invention consists of a cavity closer element adapted for use in a co-planar reveal or a check reveal having a bridge member for spanning the cavity and a body member projecting into the cavity, a plurality of adjacent hollow chambers extending perpendicularly from the bridge the chambers being adapted for selective insulation.

The closer element may be adapted to locate a door or window frame at a predetermined inset position with respect to the cavity and element having one or more chambers insulated in accordance with the inset position.

The invention will now be described by way of example only with reference to the accompanying drawings in which: Figures l.2.0l (i) to (iv) respectively show in cross section four forms of a cavity closer element for closing a lOOmm cavity; Figures 1.2.02 (i) to (iv) show respectively in cross section, four forms of cavity closer elements for closing a 75mm cavity; Figures 2.1.03 (i)- (v) show elevations of a cavity closer mechanical joint details Figures 3.1.01 (i) is a schematic view of a window fitted to a S co-planar reveal having a cavity closer and 3.1.01 (ii) and (iii) are section along the lines A-A and B-B of Fig 3.1.01 (i) Figure 3. 1.02 (i) (ii) and (iii) are similar to 3.1.01 with a different inset configuration Figure 3.1.03 (i) (ii) and (iii) are similar to Figures 3.1.02 but using flat closer elements 9003 to close the reveal and sill cavities.

Figures 3.1.04 (i)-(iii)are similar to Figures 3.1.02 illustrating a configuration in a check reveal.

Figures 4.1.01, Figures 4.1.02, Figures 4.1.03 and Figures 4.1.04 are similar to Figures 3.1.01 3.1.02, 3.1.03 and 3.1.04 respectively using corresponding closer elements adapted for a 75 mm cavity.

Table 6.1.01 (i) and (ii) are tables of calculated thermal resistance values for various cavity closer configurations for 75mm and lOOmm cavities respectively.

Referring to Figures 1.2.01, (i) -(iv) a series of lOOmm cavity closer elements 9001, 9002, 9003 and 9004 are shown in cross section. Elements 9001-9003 each has a bridge member (1) terminating with flange parts (3) at the opposed sides for bridging a 100 mm cavity as more fully described below. A body member indicated generally by numeral 5, which in use extends into the cavity between the inner leaf (indicated by the line D-D) and the outer leaf (indicated by the line C-C) of a cavity wall, is formed with a central chamber 7 flanked on opposite sides by pairs of chambers 9, 11 and 13, 15 respectively. The chamber side walls extend perpendicularly from the bridge member 1 and closed by 19, 21 extending parallel to the bridge member 1. The contiguous arrangement of multiple chambers in the thermal pathway of the closer element between the inner and outer leaves of the wall provides an intrinsically well-insulated arrangement which increases thermal resistance between the end faces 23 and 25 of the element each of which incorporates a channel member 27 for attaching brick ties which are bonded between courses of brickwork during construction.

Elements 9001 and 9002 are each provided with a upstanding rib member 17 which forms an abutment for locating a window or door jamb fitted from the outside in a co-planar reveal at a pre-determined inset position, I. In Figures 1.2.01 (i) and (ii), the inset measurements are 11.5mm and 36.5 mm respectively. These inset values are selected to allow for the use of standard 150 mm and 180 mm wide sill members with the correct 40 mm projection of the sill nose beyond the external reveal. Skimmed plasterboard (Fig 3.1.02 (ii)) covers the interior side of the closer up to the rib 17 on the upright sides of the reveal and is covered by a window board at the sill (Figure 3.1.02 (iii). In such a case, and given the intrinsic thermal resistance of the vertically compartmentalized body 5, the main thermal pathway from the interior through the closer element passes longitudinally through rib 17, if present, and in a parallel direction through the adjacent jamb (3.1.02. 2 (ii)) whether rib 17 is present or not. The pathway then follows the lines of least resistance through the external section of the bridge 1 and through cavities 15 and 29 towards the exterior side of the assembly.

To compensate for the heat loss arising from a configuration based on the 9001 closer element, (Figure 3.1.02) incremental insulation of all the closer elements in the system, including the sill closer, is required, as set out in more detail in Figure 6.1.01.

Where a window or door system is installed using closer element 9002 (or closer element 9004, as described further below) the corresponding thermal pathways are greater and it has been found that no incremental insulation of the body 1 compartments is necessary in order to comply with any current British Building Regulations.

Referring to Figure 1.2.01 (iii), a flat, cavity closer element 9003 is shown which is the same in all respects to elements 9001 and 9002 described above except that the rib 17 of elements 9001 & 9002 is absent from element 9003.

Element 9003 may be substituted for either of the elements 9001 and 9002 for the closure of the vertical sides of a reveal and is normally used as the cavity closer under the window sill. This item requires the same incremental chamber insulation corresponding to the inset position as determined by 9001 or 9002 element upright side closer elements.

Referring to Figure 1.2.01 (iv) the element 9004 is similar to element 9003 but adapted for use with a check reveal, having the same body member 5 and flange 3 for cooperating with the reveal of the inner leaf as element 9003, but having an upstanding limb 31 extending from bridge member 1 for abutment with the interior surface of the external wall leaf C-C.

Referring to Figures 3.1.02(i) -(iii) Figure (ii) shows a section along the line B-B of Figure (1) illustrating the jamb 37 of a window mounted in a co-planar reveal, the 100 mm cavity being closed by the 9001 closer element which is bonded to the wall during construction by brick ties 33 which inter-engage channels 27 of the closer element and bonded between brickwork courses during construction of the reveal.

Plasterwork 35 covers the bridge member 1 and abuts the up stand 17. The inner edge of jamb 37 abuts the exterior side of up stand 17 to provide a frame inset of 11.5 mm. As may be seen from Figure 3.1.02 (iii) which is a section of the sill system on the line A-A of Figure (i) A standard 150 mm wide sill 39 has a nose portion 41 incorporating a drip edge 43 which projects 38.5 mm clear of the external reveal. The sill cavity is bridged by flat closer element 9003 the sill inset being set to 11.5 mm by being set against the inset jambs.

The maximum thermal resistance (psi) prescribed by Building Regulations is 0.050 Wm In the configuration illustrated in Figure 3.1.02 the thermal resistance (psi) as calculated in accordance with the England /Wales Regulations is 0.057 Wml Kl and 0.067 Wml Kl when calculated in accordance with the Scottish Regulations.

Accordingly, to meet the regulations the Thermal Resistance must be reduced to below 0.050 Wml Kl which is achieved by selectively injecting insulating foam into cavities 7 and 13 in the cavity former side elements 9001 and in cavities 7 and 13 of the sill closer 9003.

Referring to the drawings 3.1.01, the configuration shown is the same in all respects as that shown in Figure 3.1.02 described above except that the inset value I is 36.5 mm set by means of closer element 9002 at the reveal to allow the use of a 180 mm sill as shown in Figure (iii). However the greater length of the thermal pathway in this configuration is such that the 9002 reveal closers and the 9003 sill closer provide psi value of 0.045 Wml Kl (England & Wales and 0.041 Wml K1 (Scotland) and no additional insulation of the closer elements is required.

Referring to the Figures 3.1.03 the 9003 (flat) closer element is used both at the reveals and at the sill to enable the inset I to be adjusted. In the configuration illustrated in Figures 3.1.03, the inset value I = 33mm. It is found that no additional insulation is required to meet current British Building regulation requirements. The thermal results of various configurations described herein are summarised for easy reference in Figure 6.1.01 Referring to Figures 3.1.04 (i) -(iii) a configuration is shown which is similar to those described above, except that the closer/window system is fitted to a check reveal 45. The 9004 Closer element is used to close the reveal cavities and the 9003 element is used to close the sill cavity. The inset is now the full width of the jamb requiring the use of a 225 mm wide sill 47 to accommodate this. In this configuration the thermal pathway through the closer elements extends the full width of the jamb and has an intrinsic psi value which complies with the Regulations.

Referring to Figures 4.1.02 (i) -(iii) the configuration illustrated is generally the same as that described with reference to Figures 3.1.02 the difference being that the 9071 closer element is used to close 75 mm reveal cavities and the 9073 cavity is used to close the 75 mm sill cavity.

The results were a psi value of 0.050 Wm1 Kl ( England Wales) and 0.060 Wm1 Kl (Scotland). Compliance was obtained by foam insulating cavities 47 51 of element 9071 and the corresponding chambers of flat sill closer 9073.

Referring to Figures 4.1.01 (i)-(iii) the configuration is similar to 4.1. 02 except that the inset value is I= 36.5 mm.

The intrinsic thermal resistance is sufficient to achieve compliance without selective insulation of the closer chambers.

Referring to Figures 4.1.03 (i) -(iii) the configuration is similar to 3. 1.03 described above except with I= 33mm except the 9073 closer element is used for the reveal and sill cavities. The configuration complies without modification.

Referring to Figures 4.1.04 the configuration is similar to Figures 3.1. 04 except that the 9074 closer for a check reveal is used at the reveals and element 9073 as the sill closer.

The configuration meets the required standards without modification.

Figure 2.1.03 (i)-(v)illustrate the mechanical joint details for connecting closer elements to provide an assembled closer system. Assembled closer systems (provided with a temporary head frame) may be used as farmers in the construction of sills and reveals in brickwork or Clockwork. 1)

Claims (5)

1. Claims 1. A cavity closer having, in use, opposed upright side closer

   elements adapted for use with either a co-planar reveal or a check reveal and a horizontal sill closer element, the closer elements each having a bridge member which in use bridges the cavity between inner and outer leaves of a cavity wall, and a body member which in use extends into the cavity, the body member being formed with plurality of adjacent, hollow chambers extending perpendicularly from the bridge member to form a series of contiguous insulating compartments.
2. 2. An cavity closer as claimed in claim 1 in which each closer element has a central compartment disposed between at least one inner compartment and one outer compartment.
3. 3. A cavity closer as claimed in claim 2 in which the inner and outer compartments may each be vertically divided into separate subcompartments providing a series five intrinsically insulating contiguous chambers.
4. 4. A cavity closer as claimed in claim 3 in which abutment means are provided along the external side of a bridge member of the vertical closer elements for locating the edges of the window frame at a required inset position with respect to the reveal opening.
5. 5. A cavity closer as claimed in any preceding claim in which the cavity closer is incrementally insulated by the insertion of insulation to one or more selected closer member compartments to offset adverse thermal flow caused by the inset configuration of the window or door surrounded by the cavity closer.