GB2362670A

GB2362670A - Doorway threshold with blocks defining sill and having a gap between leading to drainage channel

Info

Publication number: GB2362670A
Application number: GB0012242A
Authority: GB
Inventors: Christopher Douglas Hodson
Original assignee: RMC CONCRETE PRODUCTS
Current assignee: RMC CONCRETE PRODUCTS
Priority date: 2000-05-19
Filing date: 2000-05-19
Publication date: 2001-11-28
Also published as: GB0012242D0

Abstract

A threshold of a doorway comprises a first block (1) of concrete material, where the top of the block defines the sill of the doorway and a second block (2) of concrete material placed adjacent but spaced from the first block leaving a gap (10) between the blocks which leads to a drainage space (14). The top surface of one or both of the first and second blocks may slope at an angle downwards towards the gap and the blocks may be identical. The threshold may further include a water bar (17) secured to the top of the sill and a third block (3), over which portions of the first and second blocks are located.

Description

2362670 1 Improvements in or relating to doorways This invention relates

to thresholds of doorways.

It has been common practice for doorsteps to be at a height above the surrounding ground so that a person entering a building steps up upon entry. That has facilitated designs of doorstep in which the risk of water or damp entering the building is reduced.

Recently, Regulations have been introduced that require new buildings to have entrances allowing reasonable access for wheelchair users and that has led to increased interest in providing thresholds of doorways at substantially the same level as an exterior landing area from which a person approaches the doorway.

It is an object of the invention to provide a practical and economical threshold of a doorway that is suitable for use where a person entering a building via the doorway is not to be required to step up to any significant extent.

According to a first aspect of the invention there is provided a threshold of a doorway including a first block of concrete material placed in the doorway in an exterior wall of a building, the top of the block defining the sill of the doorway, and a second block of concrete material placed with a front face confronting, but generally spaced from, a rear face of the first block, the gap leading downwardly into a drainage space, which drainage space is - 2 spaced outwardly from the external face of the exterior wall of the building with the bottom of the drainage space at least 140mm below the top of the sill.

By making the threshold from blocks of concrete material arranged as defined above, it is possible to provide a threshold that is economical to produce but is also able to reduce the risk of water or damp entering the building. of particular significance in that respect to those involved in building construction is the positioning of the drainage space both outside the external wall of the building and at a depth of more than 140mm below the top of the sill. Indeed, preferably the bottom of the drainage space is 15Omm or more below the top of the sill, since a separation of 150mm between the top of the sill and surrounding land on which water may lie is a separation often provided in the case of a doorstep where a person steps up upon entering the building.

Preferably the first block is of substantially the same width as, or wider than, the doorway. In that case a single first block can provide the whole of the sill of the doorway. Similarly, it is preferred that the second block is of substantially the same width as the first block.

Preferably, the first block generally increases in height from its rear face to its front face. With such a 3 - block, water on the top of the block will tend to drain towards the rear edge where the drainage gap is situated. The first block preferably has a top face consisting of a first rear portion which slopes upwardly to a substantially level front portion, the front portion defining the sill of the doorway. Where such a slope is provided, it is preferably at an angle of less than 150 and more preferably less than 100 to the horizontal. In an embodiment of the invention described below the slope is about 50.

The second block may have a top face of a variety of shapes according to the particular requirements of a given situation. For example, the second block may generally increase in height from its rear edge to its front edge, or it may generally reduce in height from its rear edge to its front edge, or the top face of the second block may be substantially level. Where there is a slope on the second block, it is preferably at an angle of less than 150 and more preferably less than 100 to the horizontal. In an embodiment of the invention described below the slope is about 50. In the case where there is a slope on the top face of both blocks, the gradient of the slope may be substantially the same on both blocks.

The front edge of the second block is preferably at substantially the same level as the rear edge of the first - 4 substantiallv identica block; that reduces the risk of a person tripping at the junction between the blocks.

In certain cases, the first and second blocks can be 1. In that case only one type of block need be manufactured to produce both the first and second blocks and an installer need not distinguish between the first and second blocks.

It is advantageous not only that the top of the first and second blocks are at substantially the same level where they confront one another, but also that there is no significant difference in level at the junction between the top of the threshold and the final floor level, including any carpet or other floor covering, immediately inside the doorway. Preferably any difference in level between the top of the threshold and the final floor level at their junction, including any floor covering, is less than 15mm and more preferably less than lomm. Consequently in a case where a carpet covering is to be allowed for, the top of the threshold is preferably above the top of the finished floor level (the finished floor level being the level of the finished structural floor, not including any floor covering); preferably the top of the threshold is more than lomm, and preferably in the range of 15mm to 30mm, above the finished floor level in such a case. Similarly, it is advantageous that there is no in level at the junction between the and the landing adjacent to the rear block. Preferably any difference in of the threshold and the landing at significant difference top of the threshold top edge of the second level between the top their junction is less than 15mm and more preferably less than 1Omm.

Preferably a water bar member i the sill. Such a member serves as entry of water over the threshold.

s secured to the top of a further barrier to the In order that it does not provide an obstacle to wheelchair access and or a hazard to other users, it should be of limited height. Preferably it is not more than 15mm, in height.

The drainage gap is preferably formed by opposing faces of the first and second blocks and the opposing faces are preferably substantially parallel, and are also preferably substantially vertical. At least one of the first and second blocks preferably has projections on its confronting face, which projections abut the other of the first and second blocks and define the general spacing between the blocks; both the first and second blocks may have projections on their confronting faces and the projections may abut one another.

The drainage gap preferably has a width at its top in the range of about 8mm to about 20mm. The gap should be of - 6 sufficient width to allow adequate drainage of water, but should not be so great as to cause a possible hazard. In an embodiment of the invention described below the gap is about 10mm.

The drainage space at the bottom of the drainage gap is preferably substantially wider than the drainage gap.

The drainage space is preferably of substantially circular cross-section. The drainage space may be defined merely by a cavity which may be bounded at least partly by the first and second blocks, but it may also be defined by a drain pipe that is positioned below the drainage gap and that i slotted to provide drainage from the bottom of the drainage gap into the interior of the drain pipe. A single slot may be provided, preferably extending along the whole length of the pipe, or a plurality of slots may be provided.

The blocks are preferably pre-cast in large numbers and thereafter transported to appropriate sites. The blocks may be of uniform composition throughout or they may be of more complicated construction; for example, they may have cores of lightweight material and/or hollow parts. An especially advantageous arrangement may be for a top portion of the first and/or second block to be of a different composition from the remainder of the block or blocks. Such an arrangement may be employed for functional 7 reasons, for example to provide a top surface with especially good grip, or for aesthetic reasons, for example, to provide a top surface that incorporates a decorative pattern.

The top face of the first and/or second blocks may be provided with indicia thereon. The indicia may be raised or depressed from the level of the remainder of the top face. The indicia may, for example, indicate the name of the builder and/or the name of the owner of the dwelling and/or may include a trade mark.

The threshold preferably includes a third block of concrete material over which a rear portion of the first block and a front portion of the second block are positioned. The first and second blocks may be simply placed on top of the third block or the blocks may be fixed together, for example by cement. Preferably the bottom of the rear portion of the first block and the bottom of the front portion of the second block are shaped to accommodate respective upper portions of the third block. The portion of the third block underlying the first block is preferably the same size as the portion of the third block underlying the second block. Preferably the third block is substantially symmetrical about a central vertical plane extending across the width of the block. Preferably the 8 - first, second and third blocks are all of substantially the same width.

The provision of a third block is especially advantageous when the drainage space is provided in a space formed between the first, second and third blocks. For example, in the case where the drainage space is of substantially circular cross-section, the third block may have an elongate recess of semi-circular cross-section across the middle of its top face and the first and second blocks may each be formed with elongate portions of substantially quadrantal cross-section extending across the blocks at their confronting faces, whereby the blocks together define an elongate cavity of substantially circular cross-section.

The third block is also preferably pre-cast and may or may not be of uniform composition throughout.

The use of spaced concrete blocks, in particular but not exclusively where there is a third block generally below the first and second blocks with a drainage space defined between all three blocks, to form the threshold of a doorway is of considerable advantage. In a broad aspect, the present invention provides a threshold of a doorway including a first block of concrete material placed in the doorway in an exterior wall of a building, the top of the - 9 block defining the sill of the doorway, and a second block of concrete material placed with a front face confronting, but generally spaced from, a rear face of the first block, the gap leading downwardly into a drainage space. The threshold just referred to may include any of the features defined above in respect of the first aspect of the invention; in that respect, even if the drainage space is not at least 140mm below the top of the sill it is preferably at least 125mm below.

By way of example certain embodiments of the invention will now be described with reference to the accompanying drawings, of which:

Fig. 1 is a sectional side view of a threshold installed in a doorway of a building; Fig. 2 is a side view of the units forming the threshold of Fig. 1, and Fig. 3 is a side view of units for forming a modified version of the threshold of Fig. 1.

Referring first to Fig. 1, there is shown a threshold of a doorway of a building. The threshold comprises a first block 1, a second block 2 and a third block 3, each of which is moulded in the cross-sectional shape shown in the drawing and is made of concrete.

is The first block 1 is of a generally rectangular crosssection having a top face consisting of a sloping rear portion 4 that slopes upwardly from a rear edge of the block to a level front portion 5 that defines the sill of 5 the doorway.

The second block 2 is also of a generally rectangular cross-section having a top face consisting of a sloping front portion 6 that slopes upwardly from a front edge of the block to a level rear portion 7. In this example, the first and second blocks are of identical construction.

The first and second blocks have confronting faces 8 and 9 respectively, between which a gap 10 is defined. The confronting faces are parallel and vertical throughout the upper portions o-f- the blocks so that the gap 10 is of uniform width. The faces 8, 9 are each formed with circular projections (not shown) at widely spaced intervals; those projections abut one another and thereby define the width of the gap 10.

The blocks 1 and 2 are moulded with corner portions omitted at the rear of the block 1 and the front of the block 2, thereby defining a recess at the interface of the bottoms of the blocks, in which the third block 3 is received as a snug fit. As shown in Fig. 1, the third block 3 has an elongate recess 11 of substantially semi- 11 - circular cross-section extending across the centre of its top face, and the first and second blocks 1, 2 have respective elongate recesses 12, 13 of substantially quadrantal cross-section formed in their confronting faces. Thus a substantially circular drainage space 14 is defined at the interface of the three blocks immediately below the gap 10.

A front portion of the block 1 is mounted in the wall of the building and rests on a supporting portion 15 of the wall. The block 1 has a width that is selected according to the width of the doorway and, for convenience, a height chosen, for ease of construction, to match the height of two or three courses of standard bricks. In the example shown, the width of the block matches the width of the doorway; an alternative possibility is for the ends of the block 1 to be fixed in the portions 16 of the external wall on either side of the doorway. Fig. 1 also shows a water bar in the form of a sealing member 17 extending across the interior of the doorway between the opposing side portions 16 of the wall and fixed to the top of the block 1. The top of the sealing member defines the top of the threshold at its junction with the floor in the building. The sealing member cooperates with a door (not shown) mounted 12 - in the doorway to provide a seal along the bottom of the door.

The height of the front of the block 1 is chosen such that the front portion 5 is at a desired height relative to the floor level inside the doorway. In the example shown in Fig. 1, a concrete floor 18 is provided and it will be seen that the level of the floor is slightly below (in this particular example about 1Omm below) that of the front portion 5 of the block 1, so that once a floor covering is placed on the floor 18, the levels become substantially the same.

1.

A damp-proof course is provided in the external wall of the building at the level of the front portion 5 of the block 1. In the region of the threshold the damp-proof course is diverted so that the part 20A passes under the block 1 and another part 20B passes around the front of the block 1. In that way the integrity of the damp-proof course is maintained.

To the rear of the block 2 a landing 19 is provided. The landing 19 may, for example, be defined by an area of paving blocks. The top of the landing 19 is, in the The blocks 2 and 3 are of the same width as the block embodiment of Fig. 1, level with the rear portion 7 of the block 2. The threshold thus provides a substantially unimpeded access from the landing 19 to the floor 18 of the building. The access is level, apart from the sloping faces 4, 6 on the blocks 1, 2. At the same time rain water landing on the threshold is drained down the sloping faces 4, 6 into the drainage space 14 which is well below the tops of the blocks and entirely outside and spaced from the external wall of the building. Fig. 2 shows the blocks 1, 2 and 3 that together provide the threshold of Fig. 1 and includes letters indicating dimensions of particular parts of the blocks. In one particular example of the invention those dimensions are as follows:

A 50mm B C D E F G H 0( 165mm 3 7. Smm 2 Smm 12 5mm 122. 5mm 18OMM lomm 5 degrees 14 Fig. 3 shows blocks 1, 2 and 3 that together provide a threshold very similar to that of Fig. 1, with corresponding parts referenced by the same reference numerals. The first and third blocks 1, 3 of Fig. 3 are identical to those of Figs. 1 and 2; the second block 2 is identical in the region of its front face, but has a top face that consists of a front portion 6A that slopes downwardly from its front edge to a level rear portion 7A. The blocks of Fig. 3 can be employed when it is desired for 10 the landing 19 to be provided at a lower level than the floor 18 of the building. In Fig. 3 the same letters are used to indicate corresponding dimensions and further letters are used to indicate dimensions that differ from those of Figs. 1 and 2. In one particular example of the is invention where the other dimensions are as set out above with reference to Fig. 2, the further dimensions are as follows: j K 23mm 142mm It will be understood that the dimensions given above relate to particular examples of the invention only and that dimensions may be varied to suit a particular application.

is

Claims

Claims

1. A threshold of a doorway including a first block of concrete material placed in the doorway in an exterior wall of a building, the top of the block defining the sill of the doorway, and a second block of concrete material placed with a front face confronting, rear face of the first block into a drainage space, which 10 outwardly from the external but generally spaced from, a the gap leading downwardly drainage space is spaced face of the exterior wall of the building with the bottom of the drainage space at least 140mm. below the top of the sill. 2. A threshold according to claim 1, in which the bottom of the drainage space is 150mm or more below the top of the sill. 3. A threshold according to claim 1 or 2, in which the first block is of substantially the same width as, or wider than, the doorway. 4. A threshold according to any preceding claim, in which the second block is of substantially the same width as the first block. 5. A threshold according to any preceding claim, in which the first block generally increases in height from its rear face to its front face.

16 - 6. A threshold according to claim 5, in which the first block has a top face consisting of a first rear portion which slopes upwardly to a substantially level front portion, the front portion defining the sill of the doorway. 7. A threshold according to claim 5 or 6, in which the top face of the first block has a slope that is at an angle of less than 150 to the horizontal. 8. A threshold according to claim 7, in which the slope is at an angle of less than 100 to the horizontal. 9. A threshold according to any preceding claim, in which the second block has a top face which generally reduces in height from its rear edge to its front edge. 10. A threshold according to any of claims 1 to 6, in which the second block generally increases in height from its rear edge to its front edge. 11. A threshold according to claim 10, in which the top face of the second block has a slope that is at an angle of less than 150 to the horizontal.

12. A threshold according to claim 11, in which the slope is at an angle of less than 100 to the horizontal. 13. A threshold according to any of claims 1 to 8, in which the top face of the second block is substantially level.

17 14. A threshold according to any preceding claim, in which the front edge of the second block is at substantially the same level as the rear edge of the first block. 15. A threshold according to any preceding claim, in which the first and second blocks are substantially identical. 16. A threshold according to any preceding claim, in which any difference in level between the top of the threshold and the final floor level at their junction is less than 15mm.

17. A threshold according to claim 16, in which any difference in level between the top of the threshold and the final floor level at their junction is less than lomm. 18. A threshold according to any preceding claim, in which any difference in level between the rear top edge of the second block and a landing adjacent thereto is less than 15mm at their junction. 19. A threshold according to any preceding claim, in which any difference in level between the rear top edge of the second block and a landing adjacent thereto is less than 1Omm at their junction. 20. A threshold according to any preceding claim, further including a water bar member secured to the top of the sill.

21. A threshold according to any preceding claim, in which the drainage gap is formed by opposing parallel faces of the first and second blocks. 22. A threshold according to any preceding claim, in which at least one of the first and second blocks has projections on its confronting face, which projections abut the other of the first and second blocks and define the general spacing between the blocks. 23. A threshold according to claim 22, in which both the first and second blocks have projections on their confronting faces and the projections abut one another. 24. A threshold according to any preceding claim, in which the drainage gap has a width at its top in the range of 8mm to 20mm.

25. A threshold according to any preceding claim, in which the drainage space at the bottom of the drainage gap is substantially wider than the drainage gap.

26. A threshold according to claim 25, in which the drainage space is of substantially circular cross-section.

27. A threshold according to claim 25 or 26, in which the drainage space is defined by a drain pipe that is positioned below the drainage gap and that is slotted to provide drainage from the bottom of the drainage gap into the interior of the drain pipe.

19 28. A threshold according to any preceding claim, in which the blocks are pre-cast. 29. A threshold according to any preceding claim, in which a top portion of the first and/or second block is of a different composition from the remainder of the block or blocks. 30. A threshold according to claim 29, in which the top surface incorporates a decorative pattern. 31. A threshold according to any preceding claim, in which the top face of the first and/or second block is provided with indicia thereon. 32. A threshold according to claim 31, in which the indicia are raised or depressed from the level of the remainder of the top face.

33. A threshold according to any preceding claim, including a third block of concrete material over which a rear portion of the first block and a front portion of the second block are positioned. 34. A threshold according to claim 33, in which the bottom of the rear portion of the first block and the bottom of the front portion of the second block are shaped to accommodate respective upper portions of the third block. 35. A threshold according to claim 33 or 34, in which the portion of the third block underlying the first block is - 20 the same size as the portion of the third block underlying the second block. 36. A threshold according to any of claims 33 to 35, in which the third block is substantially symmetrical about a central vertical plane extending across the width of the block. 37. A threshold according to any of claims 33 to 36, in which the first, second and third blocks are all of substantially the same width. 38. A threshold according to any of claims 33 to 37, in which the drainage space is provided in a space formed between the first, second and third blocks. 39. A threshold according to claim 38, in which the drainage space is of substantially circular cross-section, the third block has an elongate recess of semi-circular cross-section across the middle of its top face and the first and second blocks are each formed with elongate portions of substantially quadrantal cross-section extending across the blocks at their confronting faces, whereby the blocks together define an elongate cavity of substantially circular cross-section. 40. A threshold according to any of claims 33 to 39, in which the third block is pre-cast.

- 21 41. A threshold of a doorway including a first block of concrete material placed in the doorway in an exterior wall of a building, the top of the block defining the sill of the doorway, and a second block of concrete material placed with a front face confronting, but generally spaced from, a rear face of the first block, the gap leading downwardly into a drainage space. 42. A threshold according to claim 41 and further including any of the features of claims 2 to 40.

43. A threshold according to claim 41 or 42, in which the bottom of the drainage space is at least 125mm below the top of the sill. 44. A threshold according to any of claims 41 to 43, in which the drainage space is spaced outwardly from the external face of the exterior wall of the building. 45. A threshold substantially as herein described with reference to and as illustrated in the accompanying drawings.