GB2339437A - Wooden decking element - Google Patents

Description

2339437 Decking Method-and ApRaratus_ The invention relates to a decking

method and apparatus and particularly to the application of such a method and apparatus to wooden decking for walkways.

Wood or wooden decking is specified in many applications as a flooring for pedestrian use. For example it is commonly specified by architects or designers in civil engineering projects, such as footbridges. In many such applications the low weight and structural strength of wooden decking are advantageous. In addition, the decorative appearance of wooden decking is liked by architects and designers. However, in outdoor applications where wooden decking can become wet, it can become very slippery and dangerous for pedestrians, leading to injuries due to falls.

Two approaches to alleviate this problem have been tried.

First, grooved decking, in which a series of parallel surface grooves have been cut, can be used to aid the drainage of rainwater from a wooden decking surface. The grooves are typically about 4mm wide, 3mm deep and spaced by about 13mm. The grooves retain or even add to the decorative appearance of wooden decking but are of limited effectiveness in making the surface less slippery and, as a wooden surface wears away through use, the grooves are worn away rather rapidly due to their small depth.

Second, it is known to glue a layer of fine stone chips over the surface of wooden decking. This is very effective in reducing the slipperiness of the surface, both wet and dry, but covers the wooden surface completely and so eliminates any decorative appearance of the wood.

C:\SPECS\39886GB.SG - 7th July 1998 2 The invention provides a method and construction as defined in the appended independent claims, to which reference should now be made. Advantageous or preferred features of the invention are defined in dependent subclaims.

In essence, the invention provides a wooden decking surface in which a plurality of grooves, recesses or holes are cut and then filled with a slip-reducing, or anti-slip material, such as an abrasive/adhesive mixture. This produces a surface which incorporates areas of exposed anti-slip material but may advantageously leave visible a significant area of the wooden decking between the areas of anti-slip material.

The invention may thus advantageously provide an anti-slip surface for wooden decking which retains the decorative wooden appearance of the decking but reduces the risk of injury to pedestrians.

In a first aspect of the invention, wooden decking may be manufactured according to the invention before installation. Alternatively, in a second aspect, wooden decking which has already been installed may be treated in situ to implement the invention.

Advantageously, decking prepared according to the invention may additionally be grooved as in the prior art for improved drainage and/or for aesthetic reasons.

Preferably, the spacing between anti-slip areas in the decking of the invention is less than about 10cm, or less than about the width of a pedestrian's shoe.

C:\SPECS\39886GB.SG - 7th July 1998 Advantageously, the anti-slip areas are arranged in parallel strips, for ease of manufacture, for aesthetic reasons, and to give good area coverage of the anti-slip surface.

If the anti-slip areas are arranged in extended lines, such as in parallel strips, the anti-slip surface may advantageously be formed by cutting extended parallel grooves in the wooden surface and filling the grooves with an anti-slip material such as an abrasive/adhesive mix.

Alternatively, grooves or holes may be cut in any other pattern and then filled with anti-slip to produce any other pattern. For example a crosshatched pattern may improve the anti-slip surface. Alternatively, a customised design or logo may be formed for decorative or advertising purposes.

Advantageously, the surface of the anti-slip material should be proud of the surrounding wooden surface to reduce slipperiness.

Preferably, the anti-slip material should have, during use, a similar wear rate to the surrounding wood. This ensures that an adequately even surface is maintained even after significant surface wear.

A wooden decking surface wears away through use faster than most other surfaces used for flooring. The grooves or holes filled with anti-slip material must therefore be sufficiently deep to accommodate the wear. In practice, the anti-slip material should initially extend to about 5mm to 8mm or more below the wooden surface to allow for wear. It should be noted that the overall wear rate might be reduced by using a very wear-resistant anti-slip material in grooves in wooden decking, but this would only occur if the area of anti-slip material were large, and if C:\SPECS\39886GB.SG 7th July 1998 4 only a correspondingly small area of wood were left exposed. The load of pedestriansf feet would then be supported mainly on the anti-slip material. However, the decorative effect of the wooden decking would then be lost. In the preferred embodiment of the invention described above, a large depth of anti-slip material is provided so that the wood and anti- slip material may wear away at similar rates. A rather small area of anti- slip material may then be provided, leaving a correspondingly large area of wood, retaining as far as possible the decorative effect of the wood. Nevertheless, the antislip material may advantageously wear slightly slower than the surrounding wood, so that it remains slightly proud of the surrounding wood and thus remains effective in reducing slipping.

Advantageously, each groove or hole for receiving the anti-slip material is flared, or tapered, so that it is narrowest at the decking surface and flares outwardly to a greater width below the surface, towards the base of the groove or hole. Preferably each groove is 5mm to 8mm or more deep, as stated above, and advantageously the width of each groove should be not more than about two or three times the depth of the groove, and particularly advantageously should be approximately equal to the depth of the groove, before wear during use.

The reasons for this are as follows. The wooden decking surface is of limited strength, and may be more flexible, and softer, than the antislip material, particularly if the latter is an abrasive/adhesive mix. It is therefore important that the anti-slip material is keyed securely into the grooves in the decking surface and mechanically supported as effectively as possible by the surrounding wood. It has been found that if an abrasive/adhesive mix is placed in a groove which is too wide compared to its C:\SPECS\39886GB.SG - 7th July 1998 depth (e.g. with width greater than about three times the depth), the mismatch in the elastic and other properties of the abrasive/adhesive mix and the surrounding wood may be sufficient to lead to cracking or mechanical failure of the abrasive/adhesive mix or the surrounding wood during use. This leads to loss of the abrasive/adhesive mix from within the grooves or holes in the wood.

According to a preferred embodiment, the anti-slip material comprises an adhesive or resin and is inserted into the grooves or holes in a malleable or liquid state before setting when in place. In that case, it has been found that, since the grooves or holes formed in wooden decking to receive the anti-slip material need to be fairly deep in comparison to their width as described above, care has to be taken to ensure that the unset antislip material is of sufficiently low viscosity to ensure that it penetrates to the base of each groove or hole. However, a preferred anti-slip material is a mixture of dried silica and calcine flint with a two-part epoxy adhesive, and if too large a proportion of epoxy is used it has been found that undesirable staining of the wood surface may be caused. It is important to achieve a compromise between these factors.

One way to make it easier to insert a higher viscosity mix into a hole or groove may be not to use a tapered hole or groove. However it has been found that this disadvantageously increases the likelihood of the mix not being held securely in the hole or groove during use, and breaking up or falling our either immediately or after a period of wear.

Advantageously, tapered grooves or holes may be cut into a wooden decking surface using a router. Preferably, masking tape is used temporarily to raise the sides of the C:\SPECS39886GB.SG - 7th July 1998 6 grooves or holes before the anti-slip material is, for example, poured or trowelled into the grooves or holes and levelled with the upper surface of the masking tape. The masking tape is then removed after the mix has set, leaving the anti-slip material slightly proud of the wooden surface, which may advantageously improve its antislip performance.

The foregoing description has referred to an abrasive/adhesive mix as an example of an anti-slip material. However, other anti-slip materials are envisaged by the invention. For example, materials incorporating rubber, or rubber chips, or stone chips, or any mixture of these may be used with advantage.

Specific embodiments of the invention will now be described by way of example, with reference to the drawings in which:

Figure 1 is a perspective view of a portion of prior art grooved wooden decking;

Figure 2 is a perspective view of a portion of prior art wooden decking covered with a layer of stone chips; Figure 3 is a perspective view of a first embodiment of the invention; Figure 4 is a cross-section of the decking of figure 3 before insertion of an abrasive/adhesive mix; Figure 5 is a perspective view of three sections of the decking of figure 3 interlocked for use; Figure 6 is a perspective view of a portion of wooden decking according to a second embodiment of the invention.

C:\SPECS\39886GB.SG - 7th July 1998 7 Prior Art

Figure 1 shows a typical example of an area of grooved wooden decking 2. The drawing (like all the drawings referred to below) shows only a short section of a much longer decking plank, along which the grooves extend. The wood is a hardwood and the grooves 4 are cut at 14mm spacing to a depth of 2.5mm. The grooves are of trapezoidal section and are approximately 5mm wide at the surface and 2mm at the groove base. This type of decking is desirable for aesthetic reasons but is slippery when wet, although the grooves assist drainage, and does not wear well because the grooves are shallow.

Figure 2 shows a perspective view of an area of a second prior art decking construction. It comprises a plain timber decking 6. A layer of glue 8 has been applied, by spraying or painting, over the whole top surface of the decking and layer of stone chips 10 stuck to and embedded in the glue. As will be appreciated, the stone chips cover the entire wooden surface, which is therefore hidden. Architects and designers seeking the decorative appearance of wood prefer to avoid this type of coating.

Embodiments of the Invention Figure 3 shows a perspective view of a short section of a length of timber decking 12 embodying the invention. The decking is approximately 25mm thick and is manufactured in extended lengths, or planks, with shaped edges 14. The shaped edges allow similar planks to be laid adjacent each other as shown in figure 5. The upper surface of the decking includes, extending along the length of the plank, a central anti-slip insert 16 and, on each side of the C:\SPECS\39886GB.SG - 7tb July 1998 insert, a shallow groove 18. The shallow grooves are for decorative effect and to improve drainage. However, as discussed above, the effectiveness of the grooves in preventing slipping is limited, particularly after the grooves have been worn during use. Further drainage is advantageously provided through the joints between adjacent planks.

Figure 4 is a cross section of the plank of figure 3 at an intermediate stage of construction before the insertion of the anti-slip insert. The cross sections of the grooves 18 can clearly be seen, separated by the larger groove 20 for receiving the anti-slip insert.

Before cutting the groove 20, a strip of thick masking tape is applied to the upper surface of the plank 12 where the groove 20 is to be cut. The groove 20 is then cut using a suitably- shaped router. Advantageously, the router may be provided with a mechanical guide which follows the drainage grooves 18. This is a useful feature, particularly if the anti-slip insert is to be fitted to an already-grooved piece of timber decking, for example if the anti-slip insert is to be retrofitted to timber decking in situ. However, if the timber decking is being manufactured with the anti-slip insert already in place before the decking is installed, the grooves 18, 20 may be cut in any convenient order.

The router cutting the groove 20 also cuts through the masking tape leaving two strips of tape 22, 24 on each side of the central groove 20. The groove 20 is 12mm wide at the decking surface, 14mm wide at the groove base and is llmm deep, measured from the decking surface. After the groove is cut, a mixture of abrasive particles in an adhesive binder is poured or inserted in any convenient way into the groove 20. the mixture is levelled with the C:\SPECS\398S6GB.SG - 7th July 1998 upper surface of the masking tape 22, 24. After the adhesive has hardened, or preferably just before the adhesive has set hard, the masking tape can be removed, leaving the abrasive/adhesive non-slip insert approximately lmm proud of the wooden surface.

Instead of applying the masking tape and cutting it with a router as described above, separate strips of masking tape 22, 24 may be applied to the decking surface on either side of the groove after the groove has been cut.

Because the insert extends above the timber surface, it is important that the binder does not seep beneath the masking tape during installation, and thus stain the wooden surface. In the embodiment, this can be achieved by reducing the binder, or adhesive, content of the mixture.

The adhesive of resin in the abrasive/adhesive mix is preferably two-part epoxy.

optionally, to improve the decorative appearance of the anti-slip insert, it may be coloured by the use of coloured particles, or a coloured binder.

The abrasive/adhesive mixture in the preferred embodiment comprises, by volume, 1 part resin PY 303-1, 1 part hardener HY 2965 (both from Ciba Speciality Chemicals p1c) 8 parts grade 50 dried silica and 1 part calcined flint 1.0mm. It is possible to deviate from this mixture to an extent, however, as long as the mixture meets the functional requirements described in this application.

Figure 5 illustrates three short sections of planks 26, 28, 30 of the timber decking shown in figures 3 and 4 laid side by side as in use. In the drawing, the anti-slip C:\SPECS\39886GB.SG - 7th July 1998 areas 16 are shaded. It can clearly be seen that the decorative appearance of the wood is retained. In the embodiment, the upper surface of each plank is approximately 75mm wide, compared with the approximately 12mm width of the anti-slip insert. More than 80% of the wooden surface is therefore still visible although the anti-slip properties of the decking have been significantly improved by the embodiment of the invention.

Figure 6 shows a perspective view of a section of timber decking 32 according to a second embodiment of the invention. In this case the timber planking is approximately 95mm wide and contains no surface drainage grooves. The insert 34 is of similar shape to the insert in the embodiment of figures 3 to 5 but is 19mm wide at the timber surface, 21mm at the base of the groove and 10mm deep below the wooden surface. The anti-slip insert is between O.5mm and Imm proud of the wooden surface.

C:\SPECS\39886GB.SG - 7tb July 1998

Claims (23)

1. A decking apparatus comprising a timber decking element having a surface for forming a walkway or the like, and a slip-reducing insert located in a groove in the decking surface, the groove section tapering outwardly towards its base and the groove width at the decking surface being less than three times the groove depth.

2. A decking apparatus according to claim 1, in which the groove width at the decking surface is less than twice the groove depth.

3. A decking apparatus according to claim 1, in which the groove width at the decking surface is approximately equal to the groove depth.

4. A decking apparatus according to any preceding claim, in which the groove depth is greater than about 8mm.

5. A decking apparatus according to any preceding claim, in which the insert is, before use of the decking, about lmm proud of the decking surface.

6. A decking apparatus according to any preceding claim, in which the groove sides taper outwardly at an angle of between about 51 to 20', and preferably between 101 and 151.

7. A decking apparatus according to any preceding claim, in which the insert is a mixture of abrasive and resin or adhesive.

8. A decking apparatus according to any preceding claim, in which the wear rate of the insert during use is similar to the wear rate of the decking surface during use.

C:\SPECS\39886GB.SG - Ah July 1998 12 -

9. A decking apparatus according to any preceding claim, in which the insert upper surface occupies less than 35%, and preferably less than 20% of the decking surface.

10. A method for making or modifying a decking apparatus having a surface for forming a walkway or the like, comprising the following steps; cutting a groove in the decking surface, the groove tapering outwardly towards its base and the groove width at the decking surface being less than three times the groove depth; and inserting a slip-reducing insert in the groove.

11. A method according to claim 10, in which the groove width at the decking surface is less than twice the groove depth.

12. A method according to claim 10, in which the groove width at the decking surface is approximately equal to the groove depth.

13. A method according to any of claims 10 to 12, in which the groove depth is greater than about 8mm.

14. A method according to any of claims 10 to 13, in which the slipreducing insert is inserted in the groove in a liquid or mouldable condition and then sets.

15. A method according to claim 14, in which the groove sides taper outwardly at an angle small enough to enable 25 the slip-reducing insert to be inserted snugly adjacent the groove sides and base.

C:\SPECS\39886GB.SG - 7th July 1998 13 -

16. A method according to any of claims 10 to 15, in which the groove sides taper outwardly at an angle of between about 51 to 200, and preferably between 101 and 151.

17. A method according to claim 14 or 15, in which masking tape is applied to the decking surface before introduction of the slip-reducing insert into the groove and the insert is levelled with the upper surface of the masking tape so that the insert, when set, stands proud of the decking surface.

18. A method according to any of claims 10 to 17, in which the insert is a mixture of abrasive and resin or adhesive.

19. A method according to any of claim 10 to 18, in which the insert upper surface occupies less than 35%, and preferably less than 20%, of the decking surface.

20. A method for modifying existing timber decking in situ as defined in any of claims 10 to 19.

21. A decking apparatus substantially as described herein with reference to figures 3, 4 and 5.

22. A decking apparatus substantially as described herein with reference to figure 6.

23. A method for manufacturing or modifying a decking apparatus substantially as described herein with reference to the drawings.

C:%SPECS\39886GB.SG - 7th July 1998