GB2407831A

GB2407831A - Joist support and method for mounting floor joists

Info

Publication number: GB2407831A
Application number: GB0326159A
Authority: GB
Inventors: Simon Grime
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-11-07
Filing date: 2003-11-07
Publication date: 2005-05-11
Anticipated expiration: 2023-11-07
Also published as: GB2407831B; GB0326159D0

Abstract

A joist support comprises a channel-shaped member having one side (3) thereof capable of pivotal movement relative to the base (1) from an open position extending in the same plane as the base of the channel and outwardly thereof to a closed position extending normally to the base. A method of mounting floor joists in a cavity wall construction comprises building an inner skin (9) of the cavity wall to a desired height for the joists, locating on the upper surface of the wall the joist support (12) with the open face of the channel directed towards the inside of the building, hinging the upper side (3) of the channel member to the open position thereof and locating joist ends (11) in the member resting on the lower side thereof, hinging the upper side to the closed position, and constructing a further part of said inner skin on the upper side of the channel member.

Description

240783 1

JOIST SUPPORT AND METHOD OF MOUNTING FLOOR JOISTS

Field of the Invention

This invention relates to a joist support and to a method of mounting floor joists.

Background to the Invention

Traditionally, floor joists have been mounted in one of two principal ways: building the joist ends directly into the walls; or using metal joist hangers which incorporate a flange built in to the wall to introduce the vertical loading on the joists into the wall. Modern walls are built as two skins, typically of bricks or blocks, with a cavity between them, into which is incorporated thermal insulation material, for example in the form of a glass or mineral fibre mat.

There is an increasing emphasis on energy efficiency in houseconstruction, and this is reflected in increasingly stringent official regulations relating to insulation which a builder is required to meet in building new structures. One area where thermal losses can occur is in gaps around built-in joist ends, since these communicate with the ventilated cavity in the wall. It is difficult to achieve a complete seal around the joist ends, and any gap will allow air flow and hence thermal losses. It is thus difficult to guarantee to meet thermal insulation requirements in building regulations when building-in the joist ends.

Although the use of joist hangers will ensure that gaps are avoided, and therefore the thermal insulation is not compromised, the transfer of load with a joist hanger depends on the tongue of metal included in the brick or block work, and so the load bearing capacity of a floor supported on joist hangers is less than that of a floor where the joists are fully supported by the wall. This reduced load-bearing capacity can have an impact where the newly-installed joists are used as a base from which to construct the upper parts of the building, and it is possible for overloading to occur, with adverse health and safety consequences.

Summary of the Invention

According to the invention, there is provided a joist support comprising a channel-shaped member having one side thereof capable of pivotal movement relative to the base from an open position extending in the same plane as the base of the channel and outwardly thereof to a closed position extending normally to the base.

The channel member is preferably formed of a plastics material, and more preferably is formed with a flexible web connecting the base and the pivoting side. The member is suitably formed as a plastics extrusion. The external faces of the sides of the channel may be provided with roughening to increase the adhesion of mortar thereto.

The roughening may be achieved by moulding a textured surface in the plastics surface or, particularly where the member is formed from a material other than plastics, by applying a coating of a roughening material, for example incorporating sand or the like.

The channel members may be provided with connecting formations at the ends thereof, whereby adjacent lengths may be connected together where the length of wall on which the joists are to be mounted is greater than that of a standard length of the channel members (which may be provided in standard lengths for convenience of manufacture and transport). In order to ensure a complete seal, stop ends may be provided to be fixed to the ends of the channel members before incorporation into a wall.

The invention also provides a method of mounting floor joists in a cavity wall construction, comprising building an inner skin of the cavity wall to a desired height for the joists, locating on the upper surface of the wall joist support comprising a channel member with the open face of the channel directed towards the inside of the building, the channel member having a lower side and an upper side spaced apart by a continuous vertical base whose height corresponds to the vertical thickness of the joists, the upper side being hingedly connected to the base so as to be hingeable between an open position extending upwardly from the base and a closed position extending normally to the base, hinging the upper side of the channel member to the open position thereof and locating joist ends in the member resting on the lower side thereof, hinging the upper side to the closed position, and constructing a further part of said inner skin on the upper side of the channel member.

The spaces between the joists within the channel members are suitably filled in with brick or block work in the usual manner, so as to provide a full support for the upper part of the wall.

It will be understood that the width of the base, and thus the height of the channel when in its installed position, will ideally correspond to the depth of the joists being used. However, the joist support is suitably manufactured in a range of standard sizes, and any difference between the height of the joists and the width of the base will readily be made up by mortar with additional block or brick where necessary.

The joist support and method of the invention provide a simple and reliable way of ensuring air-tight incorporation of the joists into a cavity wall without the use of joist hangers.

Brief Description of the Drawings

In the drawings, which illustrate an exemplary embodiment of the invention: Figure 1 is a perspective view of a joist support; Figure 2 is a perspective view of a corner connector; Figure 3 is a perspective view of a stop end; and Figure 4 is a perspective view of a section of wall having joists installed therein using the joist support of the invention.

Detailed Description of the Illustrated Embodiment

Referring first to Figure 1, the joist support comprises an extruded plastics channel section having a channel base 1, a lower side 2 extending normally thereto, and an upper side 3 connected thereto through a flexible web 4 so as to be able to hinge between the closed position as illustrated in the Figure, in which it extends normally to the base, and an open position in which it extends upwardly in the plane of the base 1.

The outer or external faces of the sides are provided with an anti-slip coating in order to key with the mortar in which the support is bedded on the upper surface of a wall, as hereinafter described, and with the mortar bed for the masonry laid on it. In order to enable separate lengths of the support to be connected together, the opposed ends are provided with respective male and female formations 5 which can be pushed together to form a substantially air-tight connection, so that a continuous run can be made up of a number of shorter channel members.

Where it is desired to extend the joist support round a corner in the wall, for example where a stairway or chimney is to be installed, a corner unit 6 may be provided, as shown in Figure 2. This is a fixed- sided connector formed from plastics material and made slightly smaller than the channel member illustrated in Figure 1 so that it fits within the member, being attached to it by means of double-sided self-adhesive tape, for example, serving to form the air-tight connection between them. It will be understood that other means of ensuring a satisfactory connection may be used, for example formations corresponding to the formations 5 provided on the ends of the channel members.

Figure 3 shows a stop end 7 used to seal the end of the channel member of Figure 1. The stop end fits within the end of the channel member and is sealed to it in the same manner as the corner unit 6, and serves to ensure that there is no communication between the cavity in the wall and the interior of the building.

Figure 4 shows a typical cavity wall, having an outer skin 8, for example of brick, an inner skin 9, for example of thermally insulating blocks, with a cavity between them filled with thermally-insulating panels or batts 10 of bonded glass fibre or mineral fibre.

To incorporate the floor joists 11 into the structure, the inner skin 9 is first built up to the desired height, and a bed of mortar is laid on the upper surface. The joist support 12 is then positioned on the mortar bed and levelled. When the mortar has set, the upper side of the channel member is hinged upwardly to permit the joists 11 to be lowered into position with the ends thereof within the support 12. The upper side is then returned to the closed position resting on the joists, permitting the remainder of the inner skin 9 to be laid on top of the joist support. The cavity is thus sealed from the interior of the building preventing heat loss.

It will be appreciated that other means of providing an air-tight seal may be employed instead of mortar, for example a layer of mastic may be provided between the top of the inner skin and the joist support. - 5

Claims

1. A joist support comprising a channel-shaped member having one side thereof capable of pivotal movement relative to the base from an open position extending in the same plane as the base of the channel and outwardly thereof to a closed position extending normally to the base.

2. A joist support according to Claim 1, wherein the channel member is formed of a plastics material.

3. A joist support according to Claim 2, wherein the base and the pivoting side are connected through a flexible web.

4. A joist support according to Claim 2 or 3, wherein the channel member is formed as a plastics extrusion.

5. A joist support according to any preceding claim, wherein the external faces of the sides of the channel are roughened to increase the adhesion thereto of mortar.

6. A joist support according to any preceding claim, comprising a plurality of separate lengths of channel member joined together by means of connecting formations at the ends of each member.

7. A joist support according to any preceding claim, wherein the ends thereof are closed by stop ends sealingly engaged therewith.

8. A joist support, substantially as described with reference to, or as shown in, the drawings.

9. A method of mounting floor joists in a cavity wall construction, comprising building an inner skin of the cavity wall to a desired height for the joists, locating on the upper surface of the wall joist support comprising a channel member with the open face of the channel directed towards the inside of the building, the channel member having a lower side and an upper side spaced apart by a continuous vertical base whose height corresponds to the vertical thickness of the joists, the upper side being hingedly connected to the base so as to be hingeable between an open position extending upwardly from the base and a closed position extending normally to the base, hinging the upper side of the channel member to the open position thereof and locating joist ends in the member resting on the lower side thereof, hinging the upper side to the closed - 6 position, and constructing a further part of said inner skin on the upper side of the channel member.

10. A method according to Claim 9, wherein the joist support is a joist support according to any of Claims 1 to 8.

11. A method according to Claim 9 or 10, comprising filling the spaces between the joists in the channel with a thermally-insulating material.

12. A method according to Claim 9 or 10, comprising filling the spaces between the joists within the channel with masonry.

13. A method of mounting floor joists in a cavity wall construction, substantially as described with reference to the drawings.