GB2381287A

GB2381287A - Water drainage for the threshold of a door

Info

Publication number: GB2381287A
Application number: GB0129950A
Authority: GB
Inventors: William Farrell
Original assignee: WINTEM Ltd
Current assignee: WINTEM Ltd
Priority date: 2001-10-25
Filing date: 2001-12-14
Publication date: 2003-04-30
Anticipated expiration: 2021-12-14
Also published as: GB0129950D0; GB2381287B; IE20010957A1

Abstract

Threshold unit 10 stops ingress of water through a door opening. Water flowing in direction A will first meet liquid permeable portion 28, which may take the form of a grate and flow through to a channel beneath the liquid permeable portion and exit the unit via drainage holes 20. The lowest part of the channel may extend below the height at which the drainage holes allow water to exit the threshold unit, in order settle out silt which may otherwise block the drainage holes. Water passing the grate may be repelled by trapper bar 36, which may also form a stop which abuts against the door when it is closed forming a weather seal. The grate may abut the trapper bar and may be removable to permit access to the channel. Preferably the threshold unit is shaped to permit location of a damp proof course between the threshold unit and the surrounding structure. Lip 26 may also be included to allow brickwork to be squarely aligned with the threshold unit.

Description

A THRESHOLD UNIT FOR AN EXTERIOR DOOR OF A BUILDING The present invention relates to a threshold unit for use with an exterior door of a building, and in particular relates to a threshold unit allowing unconstrained wheelchair access to a building.

It is desirable that all buildings should be designed and constructed such that persons with disabilities, and in particular persons that are wheelchair bound, may safely and conveniently approach and gain access to the building. In order to allow such unhindered access to the building, it is preferable that a level landing of 900mm by 900mm be provided outside the door of the building. Furthermore, the threshold provided under the door should also permit unhindered access, and consequently should therefore be of an overall height of no greater than 15mm above the aforementioned level landing.

It has however been found, in use, that the above mentioned level landing provides a substantial catchment area for rainwater to accumulate on. It will therefore be appreciated that, if the level landing has even the slightest of gradients, whether in whole or in part, towards the door of the building, any rainwater collecting on the landing will tend to flow towards the door. Additionally, wind will regularly tend to blow the collecting rain water towards the door, there being no gradient to prevent the flowing of the water in said direction.

In addition, the aforementioned shallow threshold to be specified provides little in the way of resistance to the advancing rainwater, which may be considerable in volume and be present over prolonged periods. Such a flow of water can often migrate past conventional threshold configurations, thereby leaking into the interior of the building. This problem is obviously further exaggerated when the door into the building is open, during which time relatively large volumes of water may run into the building. As will be appreciated, sustained passage of water into the interior of the building will have serious detrimental effects, for example staining/rotting/warping of the flooring surface present adjacent the door, or alternatively resulting in a health hazard by creating a slippery surface on any smooth floor surfaces.

It is therefore an object of the present invention to provide a threshold unit which is adapted to divert water away from the entrance to a building.

The present invention therefore provides a threshold unit for use with an exterior door of a building, the threshold unit comprising an upper face at least a portion of which is liquid permeable; and a channel in liquid communication with the liquid permeable portion of the upper face such as to convey, in use, liquid away from the upper face of the threshold unit.

Preferably the liquid permeable portion is removable from the threshold unit, such as to permit access to the channel.

Preferably the liquid permeable portion is substantially flush with the upper face of the threshold unit.

Preferably the liquid permeable portion is located at or adjacent the door.

Preferably at least one drainage hole extends from the channel to an exterior face of the threshold unit, such as to permit liquid to be drained from the channel.

Preferably the at least one drainage hole extends from above a base of the channel.

Preferably the threshold unit includes a trapper bar having a stop which projects above the upper face of the threshold unit such that, in use, the door abuts against the stop when the door is in the closed postion.

Preferably the trapper bar is seated in a recess provided in the upper face of the threshold unit.

Preferably the recess is in liquid communication with the channel.

Preferably the liquid permeable portion abuts against the stop of the trapper bar.

Preferably the trapper bar includes a leading edge extending from the stop, the leading edge projecting, in use, over the channel such that any water which

migrates between the liquid permeable portion and the trapper bar will be diverted into the channel.

Preferably the threshold unit is shaped to permit the location of a damp proof course between the threshold unit and any surrounding structure.

The present invention will now be described with reference to the accompanying drawings, in which; Figure 1 illustrates a perspective view of a threshold unit according to the present invention, including cut-away portions of a door frame in register with the threshold unit; Figure 2 illustrates an exploded perspective view of the threshold unit of Figure 1 ; and Figure 3 illustrates a sectioned side elevation of the threshold unit of Figures 1 and 2.

Referring now to the accompanying drawings, there is illustrated a threshold unit, generally indicated as 10, providing unhindered access, in particular for persons with disabilities, to the interior of a building (not shown). The threshold unit consists primarily of a body 12 which, in use, is sunk into the bottom of an exterior doorway (not shown) of the building, such that an upper face 14 of the body 12 is disposed substantially flush with an interior floor (not shown) of the building, and an exterior landing (not shown) which serves as an approach to the building. In this manner the threshold unit 10 is

similarly disposed to a conventional saddle board (not shown), and provides a level transition from the exterior to the interior of the building, in order to permit disabled access thereto.

In order to prevent the ingress of rainwater as hereinbefore described, the body 12 is provided with a channel 16 formed integrally therein. The channel 16 extends downwardly from the upper face 14, and is of a dimension capable of conveying large volumes of water therethrough. In use, water will flow towards the threshold unit 10 in the direction of arrow A illustrated in Figures 1 and 2. As the upper face 14 is located substantially flush with the exterior landing, the water will flow over the upper face 14, thereby encountering the channel 16 extending therefrom. The water is thus conveyed downwardly into the channel 16, preventing any passage of the water over the threshold unit 10 to the interior of the building.

It will of course be appreciated that, if the channel 16 were not provided with some form of runoff, the channel 16 would quickly fill with water, thereby negating the above described benefit thereof.

Therefore, in the preferred embodiment illustrated, the body 12 is provided with a pair of drainage holes 20 extending from a front wall 18, through the body 12, to the channel 16. Water flowing into the channel 16 may therefore exit therefrom via the drainage holes 20. In practice, each of the drainage holes 20 will be connected to any form of conventional piping (not shown) such that the water exiting from the channel 16

may be discharged to either the drainage works (not shown) of the building, or to a purpose built soak pit (not shown). It will be understood that any number of drainage holes 20 may be provided in fluid communication with the channel 16, and in addition the drainage holes 20 do not necessarily have to exit from the body 12 via the front wall 18, but may be routed to any suitable part of the body 12. Referring in particular to Figure 3, it can be seen that the drainage holes 20 extend from the channel 16, above the bottom thereof, such that any silt or similar debris mixed with the rainwater entering the channel 16 will precipitate to the bottom of the channel 16, and not be discharged through the drainage holes 20, resulting in a blockage thereof. Any such silt build up within the bottom of the channel 16 can of course be quickly and easily cleared therefrom.

Due to the relatively large volume of the channel 16, such as to enable the diversion of substantial volumes of water, it is necessary to cover the channel 16 with a liquid permeable portion such as a grating 28. This is due to the fact that the channel 16 may otherwise result in a person's foot, the wheel of a wheelchair, or the leg of a walking frame or the like catching or becoming stuck in the channel 16, possibly resulting in injury. The grating 28 includes an array of punch holes 30 therein, in order to allow, in use, the water flowing onto the upper face 14 of the threshold unit 10 to pass through the grating 28 into the channel 16. In order to ensure that the grating 28 itself does not form an obstacle to the passage of persons over the threshold unit 10, the body 12 is provided with a

recess 22 sunk downwardly into the body 12 from the upper face 14. The grating 28 includes a front edge 32 and a rear edge 34 of a depth equal to that of the recess 22, such that grating 28, when sitting within the recess 22, is substantially flush with the upper face 14. The recess 22 extends around the channel 16, and is shaped such that the grating 28 is a snug fit therein.

The grating 28 is therefore disposed above the channel 16, while still permitting the flow of water into the channel 16 via the plurality of punch holes 30. The punch holes 30 are also small enough in diameter to prevent, for example, a narrow heel of a shoe or the like from becoming lodged therein. The grating 28 may be removably secured to the body 12 by passing one or more bolts (not shown) or the like through the grating 28 and into the body 12 or any suitable fixture (not shown) mounted to the body 12. Thus the grating 28, while being securely mounted in place, can be readily removed to allow access to the channel 16 for the purposes of silt removal or the like. As used herein, the term"grating"is intended to mean any covering or surface which permits the passage of liquid, primarily water, therethrough, while providing sufficient surface area and having sufficient strength to permit and support the passage of pedestrian traffic thereover.

As can be seen form fiures 1 and 2, in use, a door frame 46 abuts against and extends upwardly from the threshold unit 10. The door frame 46 is shown as cutaway in both figures 1 and 2 for clarity. In use therefore, a door (not shown) is hingedly mounted to

one side of the door frame 46, the door extending between each side of the door frame 46, above the threshold unit 10, when the door is in the closed position. Thus, in order to form a draught and weather excluding seal between the underside of the door and the threshold unit 10, a trapper bar 36 is provided.

The trapper bar 36 consists of a base 42, extending upwardly from which are both a rear face 44 and a stop 38. Projecting forwardly of the base 42 is a leading edge 40. The trapper bar 36 is preferably formed from metal by a process of extrusion, although it will of course be understood that any other suitable material and/or process may be used to form the trapper bar 36.

The trapper bar 36 is seated within the recess 22, and in the preferred embodiment illustrated is secured beneath the door frame 46 on either side of the threshold unit 10. It will therefore be appreciated that the trapper bar 36 may be fixed to the door frame 46 prior to fitting the door frame 46 in place above the threshold unit 10, or alternatively the trapper bar 36 may initially be installed on the threshold unit 10, and the door frame 46 then secured thereto. The stop 38 projects directly upwards from the upper face 14 of the threshold unit 10, such that the stop 38 serves as an abutment against which engages a conventional weatherseal (not shown) which is secured to the underside of the door. The stop 38 should not project upwardly beyond the upper face 14 any further than is necessary, in order to allow free and unhindered passage past the stop 38.

In use, the stop 38 abuts against the rear edge 34 of the grating 28, as can clearly be seen in figures 1 and 3. Thus, in the event that any water manages to cross the grating 28, the progress of the water will be arrested by the stop 38, and the water will thus drain downwardly between the rear edge 34 and the stop 38.

This water will therefore come into contact with the leading edge 40, which extends, in use, outwardly from the stop 38 to project over the channel 16. It will therefore be appreciated that the water which drains between the rear edge 34 and the stop 38 will be directed, by means of the leading edge 40, into the channel 16. It is for this reason that the trapper bar is provided with the leading edge 40 projecting outwardly therefrom.

In the unlikely event that any water were to find it's way between the base 42 of the trapper bar 36 and the body 12, such water would still not be able to leak to the interior of the building, due to the fact that the trapper bar 36"is located within the recess 22. As at this point the water is not being driven by the force of wind or gradient, it will not be able to flow upwardly out of the recess 22 in order to pass beyond the threshold unit 10. The recess 22 therefore acts as a final barrier to the possible path of water seeping across the threshold unit 10.

The body 12 is also recessed beneath a shoulder 24 on the, in use, interior side of the threshold unit 10, such as to permit a conventional damp proof course 52 and/or a radon barrier 54 to be located between the

threshold unit 10 and any internal brickwork 50 and/or external brickwork 48, as is illustrated in Figure 3.

As a preferred optional feature, the threshold unit 10 includes a pair of oppositely disposed lips 26 formed intergrally with the body 12. Each lip 26 is shaped and dimensioned to permit the external brickwork 48, or alternative feature (not shown) abutting the threshold unit 10 to be seated within the respective lip 26, in order to allow the brickwork 48 to be correctly and squarely aligned with the threshold unit 10.

Claims

Claims 1. A threshold unit for use with an exterior door of a building, the threshold unit comprising an upper face at least a portion of which is liquid permeable; and a channel in liquid communication with the liquid permeable portion of the upper face such as to convey, in use, liquid away from the upper face of the threshold unit.
2. A threshold unit according to Claim 1 wherein the liquid permeable portion is removable from the threshold unit, such as to permit access to the channel.
3. A threshold unit according to Claim 1 or 2 wherein the liquid permeable portion is substantially flush with the upper face of the threshold unit.
4. A threshold unit according to any preceding claim wherein the liquid permeable portion is located at or adjacent the door.
5. A threshold unit according to any preceding claim wherein at least one drainage hole extends from the channel to an exterior face of the threshold unit, such as to permit liquid to be drained from the channel.
6. A threshold unit according to Claim 5 wherein the at least one drainage hole extends from above a base of the channel.

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7. A threshold unit according to any preceding claim which includes a trapper bar having a stop which projects above the upper face of the threshold unit such that, in use, the door abuts against the stop when the door is in the closed postion.
8. A threshold unit according to claim 7 wherein the trapper bar is seated in a recess provided in the upper face of the threshold unit.
9. A threshold unit according to Claim 8 wherein the recess is in liquid communication with the channel.
10. A threshold unit according to Claims 7 to 9 wherein the liquid permeable portion abuts against the stop of the trapper bar.
11. A threshold unit according to Claims 7 to 10 wherein the trapper bar includes a leading edge extending from the stop, the leading edge projecting, in use, over the channel such that any water which migrates between the liquid permeable portion and the trapper bar will be diverted into the channel.
12. A threshold unit according to any preceding claim which is shaped to permit the location of a damp proof course between the threshold unit and any surrounding structure.

13 A threshold unit substantially as herein described with reference to the accompanying drawings.