GB2213187A

GB2213187A - Cavity closer

Info

Publication number: GB2213187A
Application number: GB8830307A
Authority: GB
Inventors: David Bottomore; Colin Frederick Gibson
Original assignee: Glidevale Building and Products Ltd
Current assignee: Glidevale Building and Products Ltd
Priority date: 1987-12-24
Filing date: 1988-12-28
Publication date: 1989-08-09
Also published as: GB8830307D0

Abstract

A cavity closer for use at the end of a cavity wall structure which abuts the side top or bottom of a door or window frame, comprising an elongate closure member (200) adapted to be disposed between the cavity wall structure (204, 206) and the frame (212) in order to close said end of the cavity wall structure. The closure member has at least one elongate wall tie securing formation (208, 210) extending substantially parallel to the longitudinal axis of the closure member whereby a wall tie (216) can be secured to the wall tie securing formation at any selected axial position along the closure member. <IMAGE>

Description

CATTY CLOSER this invention relates to a cavitv closer.

It is known to provide cavitv ciosers in building structures having first and second walls defining a cavitv therebetween. The cavitv closers are usuallv aisposed at an ena of the cavity for example adjacent a door frame or a window frame.

The cavity closers mav serve a number of functions.

Principally thev serve to close the end of the cavity. In addition the mav provide a damproof course ana mav help to tie the first and secona walls too ether. The cavity closers mav also provide a fire barrier and insulation.

Examples of cavity closers are described in GB-A- 1302694. GB-Ai'-1302695 and GB-A-1302696.

According to a second aspect of the invention there is provided a cavity closer for use at the ena of a cavity wall structure which abuts the side, top or bottom of a door or window frame. said cavity closer comprising an elongate closure member adapted to be disposed between the end of the cavity wall structure and the frame in oraer to close said end of tne cavitv wall structure and at least one elongate wall tie securing formation extending substantially parallel to the lonsitudinal axis of the closer member. whereby a wall tie can be secured to the wall tie securing formation at any selected axial position along the closer member Advantageously the cavity closer further comprises a second elongate wall tie securina formation extending substantially parallel to and spaced from. the first wall tie securing formation.

Preferably the or reach wall tie securing formation comprises a substantially T-shaped recess adapted to receive a cooPeratina formation on the or each wall tie.

The wall tie securing formation enables tne wall tie to be secured at anv desired position along the closure member. Thus the wall tie can be secured to the cavity closer and to the mortar between adjacent bricks.

regardless of the size of the bricks.

In one construction the cavity closer furtner includes a deformable cavitv entering member adapted to be positioned inside the cavity in engagement simultaneousiv with both walls of the cavity wall structure, The cavitv entering member may be resilientlv deformable.

Preferablv the cavity entering member acts as a retaining means which is adapted to be secured to. or to grip. the cavity wall structure in order to retain the cavity closer in position.

Desirablv the cavity entering member comprises a cavity bridling member and two wall engaging portions disposed at opposite ends of the cavitv bridging member.

The walls can be engaged by the wall engaging member. Preferably only the wall engaging members of the second member are deformable.

The wall engaging members mav be disposed at an angle to the cavity bridging member. Preferably the wall engaging members extend in a direction towards the closure member.

The cavitv entering member mav further include a connectinq member which connects the cavitv bridging member to the closure member. Desirably the cavity entering member has an inner surface to which the connecting member is secured, and an outer surface opposite to the inner surface It is preferred that the cavitv bridging member and the closure member are substantially parallel to one another wnilst the cavity bridging member and the connecting member are substantially transverse to one another.

The closure member may be provided witn an outer surface and an inner surface: tne inner surface preferably engages the first and second walls at the end of the cavity.

The inner surfaces of the closure member the cavitv bridging member and the wall engaging members preferablY define a mortar receiving chamber. The inner surfaces may have- formations. preferably longitudinal ribs or grooves, which assist with keying of the mortar to the cavity closer: this nelps to prevent the mortar from sagging.

The mortar acts as a fire barrier at the end of the cavity wall structure.

The upper surface of the closure member and cavity entering member may have formations. preferably longitudinal ribs or grooves, which act as anti capillary formations.

The closure member and the cavitv entering member mav be integral, and may be a plastics material.

Preferably the cavity closer is formed by extrusion.

The cavitv closer preferably provides a damproof course.

The invention also provides a wall tie for use with the above type of cavity closer. The wall tie comprises a first portion adapted to be secured to the cavity wall structure and a second portion adapted to be secured to one of the wall tie securing formations. In the preferred oonstruotion tne second portion is of substantially shaped configuration. This enables the wall tie to be secured to the cavity closer by aligning the tie sucn that the axis of the head of the T-shaped second portion is parallel to the longitudinal axis of the cavity closer so that the second portion can be inserted in the wall tie securing formation. The tie may then be rotated about 900 to secure the tie to the closer. The first portion of the tie preferably comprises a substantially flat member.

according to a third aspect of the invention there is provided a cavity closer for use at the ena of a cavity wall structure which abuts the side. toP or bottom of a door or window frame, said cavity closer comprising a closure member adapted to be positioned outside the cavity between the end of the cavity and the frame and a cavity entering member adapted to be positioned inside the cavity in enqagement simultaneously with both walls of the cavity wall structure.

The cavity entering member may be resiliently deformable.

The cavity closer according to the third aspect of the invention may be provided with any combination of features of the cavity closer according to the first and second aspects of the invention.

according, to a fourth aspect of the invention there is provided a cavity closer for use at the end of a cavity wall structure which abuts the side. top or bottom of a window or door frame, said cavity closer comprising a closure member adapted to be disposed between the end of the cavity wall structure and the frame, the closer member havina at least one ventilation channel, whereby air can pass through the closure member between the cavity wall structure and the frame.

the cavity closer according to the fourth aspect of the invention mav be provided with any combination of features of the cavity closer according to the first aspect of the invention.

Preferably baffle means is provided in the or each ventilation channel.

Desirably control means is providea. the control means beina adapted to control the airflow through the closure member.

The cavitv closer according to the invention can be used with different sizes of cavity: typically the cavity is between about 50 mm and about 75 mm.

In building structures tne gaps lett for winaow frames and door frames is larger than the size of the frame itself. Thus. when the frame is fitted in tne gap it is necessarv to plug this gap with mortar or mastic.

Typical lv the gap is 5 to 10 mm and usuallv extends around the top. bottom and sides of the frame.

According to a further asPect of the invention there is provided a method of ventilating a building in the region of a window or door frame which comprises arranging a ventilator in a gap between the frame and the wall of the building structure.

The ventilator may be arranged between the top.

bottom andior sides of the frame and the wall.

This metnod can maKe use of tne natural gap between the frame anc the walls wnich is normal lav rePlaced bv mortar.

Accoraina to another aspect of the invention there is provided a building structure comprising a wall havina an aperture. a door or window frame disposed in said aperture, said aperture being dimensioned such that there is a gap between at least part of the frame and the wall, and a ventilator disposed in at least part of said gap to provide ventilation from one side of the wall to the other.

The building structure would usuallv be provided with a lintel disposed between the wall and a tvs edge of the frame. In this case. the ventilator is preferably disposed between the lintel and the frame.

The ventilator mav comprise an integral unit extending entirely across the frame.

However it is preferred to provide the ventilator in two separate ventilation units each disposed on opposite sides of the frame. This arrangement is especially useful where the ventilator is provided at the top edge of the frame underneatn tne lintel. because the lintel and frame can define a clear ventilation Pach between the two ventilation unit.

Preferably the ventilator includes two elongate strips spaced bv at least one spacer thereby defining a ventilation path between the elongate strips.

Each strip mav be provided along one ease thereof with a onannel-shaped formation. one of wnich. in use, preferaklv faces downwardly. and the other of whicn. in use. preferablv faces upwardly.

Preferably the ventilator includes a control means for controlling the cross-sectional area for air flow available tnrouah the ventilator. The control means is preferably in tne form of a 'hit and miss' air flow control device.

Reference is now made to the accompanying drawings.

in whicn: Figure 1 is a persPective view of one embodiment of a cavity closer according to the invention in a buildina structure: Figure 2 is a further perspective view of the cavitv closer according to the invention: Figure 3 is a cross-sectional view. looking from above of a building structure incorporating another embodiment of a cavity closer according to the invention: Figure 4 is a cross-sectional view of a third embodiment of cavitv closer according to the invention: Figure 5 is a cross-sectional view. looking from above.OT a building structure incorporating a fourth embodiment of a cavitv closer according to the invention: Figures t to 11 are cross-sectional views of various types of building structure incorporating a cavity closer according to the invention: Figures 12 and 13 are cross-sectional views of one embodiment of building structure according to the invention: Figure 14 is a cross-sectional view of another embodiment of building structure according to the invention: Figure 15 is a perspective view of part of a ventilator for the building structure shown in Figure 14: Figure ld is a perspective view of part of tne ventilator for the building structure shown in Figure 14:: ana Fiaure 17 is a perspective view of part of the ventilator for the building structure shown in Figure 14.

Referring to figures l and 2 a first embodiment of cavitv closer is generally designated 200. The cavity closer 200 comprises a closure member 202 which abuts an end of a cavity wall structure comprising two spaced walls 204 and 206.

The cavity closer 200 includes two wall tie receiving formations 208 and 210. Each of the wall tie receiving formations is provided with a T-shaped recess.

A window or door frame 212 engages the outer surface of the closure member 202. The frame 212 acts as a fire barrier: in certain embodiments where the frame 212 does not engage the closure member in this fashion.

then an insert. such as a rock wool insert can be provided in tne cavity. Alternativelt. the emocoiment of closer described hereinafter can be utilised. with or without the specific type of wall tie receiving formations snown in figures I and 2.

A plaster covering 214 is provided on the outer surface of the closure member 202 and abuts against the frame 212. In practice tne covering 214 is dlsPosea on the inner wall of the cavity wall structure.

The formation 208 forms a projection on the outer surface of the closure member 202 whicn serves the dual function of providing a kev into the plaster covering 214.

Between the formations 206 and 208 there are provided longitudinal ribs which act as a moisture barrier.

n plurality of wall ties 216 are provided for securing the closer 200 to the walls 202 and 204. Each wall tie 216 comprises a first portion 218 and a second portion 22.

The first portion 218 is substantially T-shaped and can be received in and securea to one of the formations 20e or 208. The second portion is substantially flat and is of relatively large cross-sectional area. so that it can be securelv embedded in mortar 205 between adjacent courses of bricks in the walls 204 or 206.

The method of securing the wall tie to the formation 206 is shown in figure 2 it will be appreciated that a similar method of securing is used with the formation 208. First the tie 216 is oriented with the second portion parallel to the longitudinal axis of the closer 200. and the head of the T of the first portion 218 also parallel with this axis. In this orientation the first portion can be inserted in the formation 206. The tie 216 is then rotated through about 90 degrees in order to secure the tie 216 to the formation 206.

The tie 216 mav be slid up and down the closure member 702 in order to select the correct position.

Referring to Figure 3 a building structure comprises a first or outer leaf 10 and a second or inner leaf 12 defining a cavity 14 therebetween. The inner leaf 12 is provided with internal plaster 16 thereupon.

cavitv closer 18 is Qlsoosed at one end of the cavity 14 in engagement with the outer and inner leaves 10 and 12.

The cavitv closer comprises a closure member 20 whicn is provided with an inner surface 22 and an outer surface 24. The inner surface is provided with ribs 20 whilst the outer surface is provided with anti capillary grooves (not shown in Figure 3).

The cavity closer 18 also includes a cavity entering member whicn comprises a connecting member 30. a cavity bridging member 32 and two wall engaging members 34. The connecting member 30 is connected between the closure member 20 and the cavity bridging member 32. The wall engaging members 34 are provided on opposite ends of the cavity bridging member 32. and are in engagement with a respective one of the inner and outer leaves 10 and 12.

The cavity bridging member 32 is provided with an inner surface 36 and an outer surface 38. Similarly, each wall engaging member 34 is provided with an inner surface 40 and an outer surface 42.

The inner surface 36 of the cavity bridging member 32. and the inner surface 40 of the wall engaging members 34. are provided with ribs 44 . also . the connecting member 30 is provided with ribs 4e.

The closure member and the cavity entering member define a chamber 48 therebetween. The chamber 48 is divided into two bv the connecting member 30. The chamber 48 is filled with mortar 50; the ribs 26. 44 and 46 helP to kev in the mortar. and help to prevent the mortar sagging.

The outer surface 38 of the cavity bridging member 32. and the outer surface 42 of the wall engaging members 34. is provided with anti capillary ribs 52.

A wall tie fixing formation 54 is Proviaee on the outer surface 38 of the cavity bridging memoer 32. The wall tie fixing formation 54 is adapted to be secured to two wall ties 56. One of the wall ties 56 is secured between the wall tie fixing formation 54 and the inner leaf 12. whilst the other wall tie 56 is secured between the wall tie fixing formation 54 and the outer leaf 10.

The cavity closer 18 is disposed aulacent tne side of a window frame 58: the window frame 58 is secured to the outer surface of the first member 20. It will be appreciated that the cavity closer 18 can also be used at a door frame.

Figure 4 shows an alternative embodiment of cavity closer 18 . The cavity closer 18 is very similar to the cavity closer 18. and like parts have been designated with like reference numerals. In Figure 4 the anti capillary grooves on the outer surface 24 of the first member 20 have been shown. and are designated bv reference numeral 28.

The onlv difference between the cavitv closer 18'.

and the cavity closer 18. is that the connecting member 30 is secured to the closure member 20 at a different position.

In Figure S the fourth embodiment of cavity closer 18 @ is shown.

The cavity closer 18'' is similar to the cavity closer 18. and like parts have been designated with like reference numerals.

In Figure 5. the first member 22 comprises spaced members 22' which define an air passageway 60 tnerebetween. The air passageway 60 enables air to flow from one-side of the frame 58 to the other.

Arrows A designate an air flow path througn the cavity closer 18@@ In Figures u to II various configurations of the cavitv closer 18' are illustrated in different types of building structure. although the cavity closer 18' shown in Figures 6 to il are different from one another and are silently different from the cavitv closer l8 shown in Figure 5 for simplicity thev have all been defined bv the same reference numeral.

The building structure shown in Figure 6 is the same as the structure shown in Figures 3 and 5. The oavity closer 18'' shown in Figure 7 is the same as the cavity closer 18'' shown in Figure 5. except that the closure member 20 includes flanges 64 along opposite edges thereof.

Figure 7 snows a building structure in which tne inner leaf 12 is snorter than the outer leaf 10. The cavity closer 18' has the connecting member closer to one edse of the first member 22 than the other. as shown in Figure 4.

In Figure 8 the building structure is the same as in Figure 6. and the cavity closer 18 is provided with a flange 64 at onlv one edge of the closure member 22, l.e.

the end adiacent the inner leaf 12.

In Figure 9 the cavity closer 18'' is shown at the top of the window frame 58. The building structure is provided with a lintel 66: the cavity closer 1E'' is not provided with the second member at all. due to the Presence of the lintel 56. It will be noted that the cavitv closer 18 enables moisture to be drained from the ventilation channel 60. If desired the lower spaced member 22' may be disposed at an angle to the horizontal in order to assist the flow of the moisture. Usually the lower spaced member 22' would be arranged so that the moisture flows towards the outside.

In Figure iO the building structure is the same as in Figure 9. except that the lintel 66 is not provided, and the cavity closer 18 is provided with the cavity entering member.

In Figure 11 the cavity closer is is disposed underneath the window frame 58. in the region of a window sill 68.

One of the flanges 64 is secured to the lower spaced member 22', whilst the other of the flanges 64 is secured to the upper spaced member 22'. The arrangement is such that moisture can drain from the inside to the outside.

The ventilation channel 60 can be provided with baffles tnot shown). and a grille or mesh can be provided at the opening defined at the edges of the closure member 22.

When the closure device 18'' is fitted at the side of the frame 58. any moisture in the channel 60 drains naturally, The grille or mesh mav be an insect grille for preventing the ingress of insects. The baffles mav be adsiustable. so that the rate of air flow can be controlled.

Figure 12 shows a window or door frame ventilator 106. As shown in Figure 12. a portion 1109 of a window frame is disposed between an external sill 116 and an internal sill 118; the external sill llb is disposed on the outside of the building, and the internal sill 118 is disposed on the inside of the building.

The frame Portion llOc is disposed above a cavitv wall structure which comPrises an outer leaf 120 and an inner leaf 122. Mortar 124 is provided between the leaves 120 and 122. and extends partially over the upper surface thereof. Plaster 126 is provided on an internal face 122a of the internal leaf 122.

The ventilator 106 defines a ventilation channel between the inside and outside of the building. This channel extends between the frame portion 110c and the internal sill 118, and between the frame portion 110e and the leaves 120 and 122.

The ventilator 10t comprises a plurality of elongate plastics extrusions. The extrusions can be assembled and supplied as a comPlete unit. or can be assembled on site bv the person installing the ventilator lO. The latter assemblv technique has the advantage that the installer can select the sizes of extrusion appropriate to the particular window.

The ventilator 106 comprises an inlet portion 128 and an outlet portion 130. which are connected by a bodv Dortion 132.

The inlet portion 128 comprises two elongate members 134 and 13o separated bv a racer 138 to define a ventilation channel between the members 134 and 136. The member 134 is provided with formations 134a which are adapted to cooperate with formations 138a on tne spacer 138. to secure the spacer 138 to the member 134. The member 136 is provided with formations 136a which are adapted to cooperate with formations 138b on the spacer 138. to secure the spacer 138 to the member 136.

Fixing means in the form of a nail or screw (not shown) can be passed through the members 134 and 136. and the spacer 138 to secure the inlet portion 128 to the frame portion 110. For this purpose preformed apertures (not shown) can be provided in the members 134 and 136.

and in the spacer 138.

The outlet portion 130 comprises two elongate members 140 and 142 which are separated bv a spacer 144 to define a ventilation channel between the members 140 and 142, The member 14u is provided with formations 140a which are adapted to cooperate with formations 144a on the spacer 144. to secure the spacer 144 to the member 140. The member 142 is provided with formations 142a wnich are adapted to cooperate with formations 144b on the spacer 144. to secure the spacer 144 to the member 142.

Fixing means in the form of a nail or screw (not shown) can be passed through the members 140 and 142, and the spacer 144, to secure the outlet portion 130 to the frame portion 11. For this purpose. preformed apertures not shown) can be provided in the members 140 and 142.

and in the spacer 144.

The outlet portion 130 is provided with a weathering member 14orb. which comprises a downwardly extending extension of the member 140. The weathering member 140b serves to inhibit the flow of rain into the ventilator and to act as a baffle against high wind velocities.

The members 134 and 142 are provided with extensions 134b and 142b respectively which overlap to form the body portion 132. The extensions 134b and 142b abut the mortar 124 to define a ventilation channel 146 between the bodv portion 132 and the frame portion 1100.

If desired similar extensions can be provided on the members 136 and 140. which abut against the frame portion bloc; however the omission of these extensions results in savings in material and does not significantly affect the effectiveness of the ventilator.

The inlet portion 128 is provided with control means generally designated 148. The control means 148 includes an elongate fixed member 150. an elongate movable member 152 and an operating member 154 secured to the movable member 152 for movement therewith.

The fixed member 150 is provided with formations 150a and 150b adapted to cooperate respectively with formations 134c on the member 134 and formations 136b on the member 136: this enables the fixed member 150 to be secured to the members 134 and 136.

The fixed member 150 is provided with a plurality of apertures 156 which are disposed in a row extending substantially parallel to the longitudinal axis of the fixed member 150 (i e. the axis normal to the plane of the drawingj. The apertures 156 are preferably elongate with a longitudinal axis extending substantially normal to the longitudinal axis of the fixed member 150.

The fixed member 150 is provided with opposing formations in the form of grooves 158: the movable member 152 is slideably received in the grooves 158.

The movable member 152 is provided with a plurality of apertures 160 which are disposed in a row which extends substantially parallel to the longitudinal axis of the movable member 152, The apertures 160 are preferably elongate with a longitudinal axis extending substantially normal to the longitudinal axis of the movable member 152.

The distance between the apertures 150 is substantially eaual to the width of the apertures 156 measured along the longitudinal axis of the fixed member ISO, The distance between the apertures 160 is substantially equal to the width of the apertures 160 measured along the longitudinal axis of the movable member 152.

The movable member 152 can be moved relative to the fixed member 150 bv pushing the operating member 154 in a direction along the longitudinal axis of the members 150 and 152.

Thus. when the apertures 156 and 160 are aligned maximum air flow through the ventilation channel 146 is permitted; when the apertures 156 and 160 are completely unaligned then substantiallv no air flow will be permitted. Intermediate positions will allow an inner mediate amount of air flow.

Figure 13 shows a ventilator 101.

In Figure 13 the leaves 120 and 122 are separated by a cavity 162 which is not filled with mortar. A lintel 164 is provided over the leaves 120 and 122 in the region of the cavity 162.

The ventilator 101 defines a ventilation channel 146' between the inside and outside of the building, This channel 146' extends between an upper portion llûa of the window frame and the leaves 120 and 122.

The ventilator 101 comprises a plurality of elongate plastics extrusions The extrusions can be assembled and supplied as a complete unit or can be assembled on site bv the person installing the ventilator. The latter assemblv technique has the advantage that the installer can select the size of extrusion appropriate to the particular window, The ventilator 101 comprises an inlet portion 128 and an outlet portion 130' , which are connected by a bodv portion 1322.

The inlet portion 128' comprises two elongate members 134' and 136' separated bw a spacer 138' to define a ventilation channel between the members 1342 and 136. The member 134' is provided with formations 134a which are adapted to cooperate with formations 138a' on the spacer 138'. to secure the spacer 138' to the member 134' The member 136' is provided with formations 136a which are adapted to cooperate with formations l38b" on the spacer 138'. to secure the spacer 138' to the member 136'.

Fixing means in the form of a nail or screw (not shown) can be passed through the members 134' and 136-.

and the spacer 138'. to secure the inlet portion 128 to the frame portion 110a. For this purpose. preformed apertures (not snown) can be provided in the members 134' and 136' and in the spacer 138'.

The outlet portion 130' comprises two elongate members 140' and 142' which are separated by a spacer 144' to define a ventilation channel between the members 140' and 142'. The member 140' is provided with formations 14Oa' which are adapted to cooperate with formations 144a on the spacer 144', to secure the spacer 144' to the member 140'. The member 142' is provided with formations 142a' which are adapted to cooperate with formations 144b' on the spacer 144', to secure the spacer 144' to the member 142'.

Fixing means in the form of a nail or screw (not shown) can be passed through the members 140' and 142', and the spacer 144', to secure the cutlet portion 130 to the 'frame portion l1Oa. For this purpose, preformed apertures (not shown) can be provided in the members 140' and 142', and in the spacer 1442.

The outlet portion 128 128' is provided witn a weathering member l4OLw'. which comprises an upwardly extending extension of the member 140' . The weathering member 140b' serves to inhibit the flow of rain into the ventilator and to act as a baffle against high wind velocities.

The members 134 and 142' are provided with extensions 134b' and 142b' respectively which overlap to form the body portion 132'. The extensions l34b' and 142D abut the lintel 164 to define a ventilation channel 146 between the bodv portion 132' and the frame portion llOa.

If desired similar extensions can be provided on the members 136' and 140', which abut against the frame portion ll0a: however the omission of these extensions results in saving in material and does not significantly affect the effectiveness of the ventilator.

The inlet Portion 17r is provided with control means generally designated 148'. The control means 148' includes an elongate fixed member 150 . an elongate movable member 152' and an operating member 154' secured to the movable member 152 for movement therewith.

The fixed member 150' is provided with formations 150a and 150b' adapted to cooperate respectively with formations 1340' on the member 134' and formations 130b' on the member 136': this enables the fixed member 150 to be secured to the members 134' and 13u'.

The fixed member 150 is provided with a plurality of apertures 156' which are disposed in a row extending substantially Parallel to the longitudinal axis of the fixed member ISO' ti.e. the axis normal to the plane of the drawin). The apertures 156" are preferably elongate with a longitudinal axis extending substantially normal to the longitudinal axis of the fixed member 150' - The fixed member 150' is provided with opposing formations in the form of grooves 158' ; the movable member 152' is slidably received in the grooves 158'.

The movable member 15S' is provided with a plurality of apertures 160 which are aisposec in a row which extends substantially parallel to the longitudinal axis of the movable member 152' . The apertures 160 are preferably elongate with a longitudinal axis extending substantially normal to the longitudinal axis of the movable member 152'.

The distance between the apertures 156' is substantially equal to the width of the apertures 156 measured along the longitudinal axis of the fixed member 150 . The distance between the apertures 160' is substantially equal to the width of the apertures 160' measured along the longitudinal axis of the movable member 152'.

The movable member 152 can be moved relative to the fixed member 150 by pushing the operating member 154' in a direction along the longitudinal axis of the members 1502 and 152' Thus when the apertures 156' and 160' are aligned maximum air flow through the ventilation channel 146' is permitted: when the apertures 156' and 160' are completely unaligned then substantially no air flow will be permitted. Intermediate positions will allow an intermediate amount of air flow.

Referring to figures 14 to 17 a building structure comprise a door or window frame 300, a wall 302 extending around said frame and defining an aperture in which the frame is received. A lintel 304 is disposed in a gap between an upper section of the frame 300 and the wall 302 and a ventilator 306 is disposed in a gap between the lintel 304 and the frame 300; usually this gap would be filled with mortar or mastic. Typically the wall 302 would be a cavitv wall structure.

The ventilator comprises two units 308 and 310. The unit 308 comprises two elongate extrusions 312 and 314 which are separated bv a spacer 316. The spacer 316 mav be provided with air flow channels to permit air to flow therethrouah. The extrusion 312 is provided with an upwardly protecting channel 316 whilst the extrusion 314 is provide with a downwardly projecting channel 318. The channel 316 is wider than the channel 314. The unit 308 is designed so that it can be turned upside down so that it can be selected whether the wider channel 316 faces up or down. Certain types of roof structure (for example where there is no overhang above are more suited to the structure in which the channel 216 faces down.

The unit 310 basicallv comprises a ventilating unit with a "hit and miss:' arrangement for controlling the cross-sectional area available for airflow.

The unit 310 comprises a first Portion which partly overlies the top of the frame 300. and which defines a channel 320 for receiving plaster 322. The unit 301 is provided with a plurality of apertures 324 arranged in a row. Grooves 326 are provided on each side of the apertures for receiving slidablv an apertured airflow control member 328. The member 328 can be slid between a position in which it completely blocks the airflow and a position in wnich it does not affect the air flow. A cover 330 is disposed at one end of the unit 310 and serves to house an operating member for sliding the member 328. A cord (not shown) mav be secured to the operating member and may hang therefrom so that an operator can use the cord to alter tne amount of ventilation; such a cord-operating system is, in itself, conventional.

Claims

1. # cavitv closer for use at the end of a cavity wall structure which abuts the side. toP or bottom of a door or window frame. said cavity closer comprising an elongate closure member adapted to be disposed between the cavity wall structure and the frame in order to close said end of the cavity wall structure. and at least one elongate wall tie securing formation extending substantially parallel to the longitudinal axis of the closure member. wherebY a wall tie can be secured to the wall tie securing formation at any selected axial position along the closure member

2. A cavity closer according to Claim 1. further comprising a second elongate wall tie securing formation extending substantially parallel to, and spaced from, the first wall tie securing formation.

3. A cavity closer according to Claim 1, wherein the or each wall tie receiving formation comprises a substantially T-shapeo recess adapted to receive a similar shaDed recess on the or each wall tie.

4. M cavity closer according to any preceding claim.

wherein the cavity closer further comprises a deformable cavity entering member provided on the closure member, said. cavity entering member being adapted to engage simultaneously both walls of the cavity wall structure.

5. A cavity closer according to Claim 4. wherein the cavity entering member is resiliently deformacle.

6. A cavitv closer according to any preceding claim, wherein the cavitv entering member comprises a cavity bridging member and two wall engaging portions disposed at opposite enos of the cavity bridging member.

X h cavity closer according to Claim 6. wherein the wall engaging members are disposed at an angle to the cavity bridging member.

8. A cavity closer according to Claim 6 or 7, wherein the wall engaging members extend in a direction towards the cavity closure member.

9. # cavity closer according to any of Claims 6 to 8.

wherein the cavity entering member further includes connecting member which extends between and which connects the cavity bridging member and the cavity closure member

10. A cavity closure according to any of Claims b to 9 wherein the cavity bridging member. the wall engaging members and the cavity closure member mutually define a mortar receiving chamber. wnereby mortar can be disposed in said chamber to provide a fire barrier at the end of the cavity wall structure

li. v cavitv closer according to any preceding claim, wherein the closure member is provided with at least one ventilation channel. wherein air can Pass through the closure member between the ena of the cavity wall structure and the door or window frame.

12. A cavitv closer according to Claim 11. wherein baffle means is disposed in the or each closure member.

13. A cavity closer according to Claim II or 12. wherein control means is provided on the closure member said control means being adapted to control the air flow through the closure.

14. A cavity closer for use at the end of a cavity wall structure which abuts the side. top or bottom of a door or window frame. substantially as herein described with reference to and and shown in tne accompanying drawings.

IS. ss wall tie for use with a cavity closer according to any preceding claim comprising a first portion adapted to be secured to the cavitv wall structure and a second portion adapted to be secured to one of the wall tie receiving formations.

16. A wall tie according to Claim 15. wherein the second portion is of substantially T-shaped configuration

17. A method of ventilating a building in the region of a window or door frame which comprises arranging a ventilator in a gap between the frame and a wall of the building structure.

18. A building structure comPrising a wall having an aperture. a door or window frame disposed in said aperture. said aperture and frame being dimensioned such that there is a gap between at least part of the frame and the wall. and a ventilator disposed in at least part of said gap to provide ventilation from one side of the wall to the other.

19. A building structure according to Claim 18 further comprising a lintel disposed between the wall and an upper edge of the frame, and wherein said ventilator is disposed between said lintel and said upper edge.

20. A building structure according to Claim 18 or 19.

wherein said ventilator comprises two separate units disposed on opposite sides of the frame.

21. A building structure according to Claim 18. 19. or 20. wherein said ventilator includes two elongate strips spaced by at least one spacer. therebY defining a ventilation path between the elongate strips.

22. A building structure according to Claim 21. wherein each strip is provided along an edge thereof with a channel shaped formation one of which. in use. faces downwardly. and the other of which. in use. faces upwardly.

23. A building structure according to Claim 18. 19 20.

21 or 22. wherein the ventilator includes control means for controlling the cross-sectional area for airflow trough the ventilator

24. A building structure according to any of Claims 18 to 23. wherein the wall is a cavity wall. and a cavity closer is provided at the end of the cavitv wall adjacent the frame.

25. A building structure according to Claim 24, wherein the ventilator forms at least part of the cavity closer.

26. A building structure substantially as nerein described with reference to and as shown in the accompanying drawings.