The present invention relates to a method and apparatus for use with underfloor pipes.

Conventionally, underfloor pipes, such as water pipes are accommodated and loosely held in notches in the joists supporting the floorboards. These are cut into the joists, the pipes are laid in position and the floorboards are subsequently nailed down to the joists. Problems of support can arise as the edge or the whole of a floorboard running transverse to the joist may be positioned over a line of notches in the joist, leading to uneven support over the length of the floorboard. Any uneveness in the joists or support can result in raised or at least uneven floorboards, which, because they are rigid and do not distort easily to accommodate any underlying distortions, results in a non-level floor. Furthermore, depending on the abilities of the plumber the notch may be too large or too small for a particular pipe such that the pipe either rattles around in the notch or may be put under pressure by the sides of the notch if the pipe expands. These problems particularly arise with water or central heating pipes where trapped air can cause vibration of the pipes and passage of hot fluid can cause expansion of the pipes.

According to the present invention there is provided a method of fitting underfloor pipes comprising cutting a notch in a joist, placing the pipe in the notch and retaining the pipe in the notch by means of a pipe retaining element, the pipe retaining element comprising a channel configured to retain loosely the pipe in place in the notch, means to fix or retain the element in the notch and a flat supporting surface, the depth of notch being chosen to match the height of the element such that the flat supporting surface is substantially level with

SUBSTITUTE SHEET

the top surface of the joist when fixed or retained in place.

Use of a pipe retaining element as claimed above overcomes the problems of the prior art method of fitting pipes and enables full support to be given to the subsequently laid floorboards, as those that overlap the edges of the notch will be held up by the flat supporting surface of the pipe retaining element. This supporting surface is substantially level with the top surface of the joist in use and therefore level floorboards may be laid without any additional work being required to compensate for the notches in the joists or the presence of the pipe retaining elements therein. Furthermore, the element is dimensioned or shaped so as to fit snugly in the notch so as not to interfere with the top surface of the joist adjacent to the notch. It may be necessary to hammer nails, or fix screws into the joist to retain floorboards in this region and the present invention allows this to be done. Similarly, use of a retaining element with a channel configured to match a known pipe enables the pipe to be loosely held to avoid unwanted vibration whilst allowing the pipe to expand if necessary.

Advantageously, the method includes providing a pipe retaining element of a width chosen to match the width of the joist. This enables the best support to be provided, particularly if the floorboards are laid transverse to the direction of the joists.

In the preferred embodiment, there is provided a pipe retaining element with an impenetrable flat supporting surface. The term 'impenetrable' in this context refers to a material at least resistant to penetration by nails hammered in by hand, e.g. a metal sheet. Previously, nails could be accidentally driven through the floorboards into the pipes causing the pipes to leak. Depending on the extent to which the nail seals the hole in the pipe such leakage can be relatively slow

and may only come to light after some time when damage has been done to the underfloor area. Use of a pipe retaining element having an impenetrable upper supporting surface provides a shield for the pipe below such that any nails driven into the floorboard will be stopped or deflected by the pipe retaining element. The person driving in the nail will be immediately aware that he has hit the element and will be warned of the presence of the pipe. A metal supporting surface provides a particularly impenetrable shield for a pipe and has the added advantage of making the element easily detectable by hand-held metal detecting devices used in the trade to locate nails or the like. This can be useful to enable location of the pipe after the floorboards have been put in place, particularly if the pipe is a plastic one. Alternatively, a suitable plastics material may be used to provide an impenetrable shield.

The method may further comprise providing a pipe retaining element of a two piece construction comprising an upper plate of impenetrable material and a lower body part. This has the advantage of reducing cost, as the lower body may be formed of any suitable material such as a moulded plastic, whilst the potentially more expensive impenetrable material can be restricted to a single plate. Provision of an element comprising a lower body of moulded plastics and an upper plate of metal is particularly preferred, as a moulded plastic body is inexpensive to produce and has the advantage that it may be used to retain metal pipes whilst avoiding the problems of metal to metal contact that would occur if an all metal element would occur. Such problems can include wear of the metal pipe due to friction and problems with earthing where the pipe is used to provide an earthing line.

The upper plate and lower body may if desired be secured together by any suitable means, such as adhesive or by pegs or guide elements formed in the body to engage

with holes in the plate or to retain the edges of the plate.

The pipe retaining element may be provided with one or more removable inserts adapted to engage with the channel of the element to define a smaller inner channel, such that the element may be used with pipes of larger or smaller dimensions, depending on the presence or absence of an insert. This provides a particularly adaptable element which may be used with varying dimensions of pipes, as required, and avoids the need for providing different elements for different pipes.

The pipe retaining element may be further formed with a plurality of channels so as to enable the element to be fitted over a plurality of pipes running together. This embodiment may also comprise one or more removable inserts adapted to engage one or more of the channels. This enables a single element to be used with, for example, two pipes of the same large diameter; two pipes of the same small diameter and two pipes of different diameters.

Viewed from a further aspect, the present invention provides a pipe retaining element suitable for use with a method as defined above. This includes a channel configured to retain loosely a pipe of known dimensions, means for fixing or retaining the element in a notch in a joist and an impenetrable flat supporting surface, the element being dimensioned such that the impenetrable flat supporting surface can be arranged to be substantially level with the top surface of the joist and the element fits snugly in the notch in the joist when fixed or retained in place, the element being thereby adapted to provide support and to shield a pipe in use.

Preferably, the upper supporting surface is formed of metal. As discussed above, this give rise to a number of advantages in use. The element may comprise a two piece construction comprising an upper plate and a lower body part, formed of, for example, metal and moulded plastics respectively.

The pipe retaining element may be provided with one or more removable inserts. The pipe element may be formed with a plurality of channels. This is particularly advantageous where one or more inserts are also provided. The invention further extends to a kit comprising any combination of one or more pipe retaining elements adapted to fit a single pipe, one or more pipe retaining elements adapted to fit a plurality of pipes and one or more inserts for the elements. Choice of suitable combination of elements and inserts, e.g. a number of single pipe elements and a number of double pipe element and inserts for each channel, can enable a single kit to be used in almost any circumstances.

There will now be described preferred embodiments of the invention, by way of example only, and with reference to the accompanying figures, in which:

Fig. 1 is a lateral view of a pipe retaining element according to an embodiment of the invention in place in a joist; Fig. 2 is a plan view of the pipe retaining element of Fig. 1;

Fig. 3 is a side view of a pipe retaining element according to a further embodiment of the present invention; Fig. 4 is a plan view of the embodiment of Fig. 3 ; and

Fig. 5 is a side view of a further embodiment of the present invention.

Referring to Fig. 1, there is shown a pipe retaining element 1 in place in a notch 2 formed in a joist 3 and surrounding a pipe 4. The pipe retaining element 1 is of a two-part construction comprising a moulded plastics body 5 together with a metal plate 6 fixed to the body 5 by an adhesive. In an alternative embodiment the moulded plastics body may comprise a number of projections on the top surface of the body at each corner which surround the metal plate and between which it may be inserted to be held in place, or which may be melted down to hold the

plate in place. The pipe retaining element 1 is shown in position placed around a pipe 4 which rests inside a channel 7 extending through the body of the element. The pipe retaining element 1 also includes means for fixing or retaining the element in the notch in the joist. In this embodiment this means is in the form of a securing hole 8 which extends through the metal plate 6 and plastics body 5. Alternative fixing methods include using adhesives or the action of the resilient deformation of the element upon insertion into the notch. Furthermore, flanges may be employed to simply act on the sides of the joist to retain the element in the notch.

Referring to Fig. 2, the element has a width W chosen to match the standard width of a joist and is of a length L.

In fitting a pipe according to the present invention, firstly, a notch 2 is cut into joist 3 corresponding to the height H and length L of the pipe retaining element. The notch may be cut through use of a template to define the shape of the notch and which may be aligned with the edge of an adjacent floorboard running transverse to the joist 3 at a distance from the joist. This enables notches to be cut at the same position relative to the adjacent floorboard along the whole length of the pipe run. Once the notch 2 has been formed, the pipe 4 and retaining element 5 are arranged in the notch 2 as shown in Fig. 1. Thereafter, the element 1 is secured to the joist 3 by means of a screw extending through the hole 8 into the joist 3. This procedure is done at all points along the length of pipe where it crosses a joist.

Once secured to the joist the floorboards overlapping the notch 2 may then be placed in position. The plate 6 of the element 1 provides a flat upper surface which can support the floorboards overlapping into the notch. This flat surface is substantially level with the upper surface of the joist and thus a continuous, level support is provided for the overlying

floorboards without the need to cut further rebates in the joist or insert extra devices into the notch to achieve this. The present invention thus allows for perfectly flat floorboards, which are greatly desired, to be laid easily over pipes.

The channel 7 retains the pipe 4 loosely in place to suppress the vibration whilst allowing expansion of the pipe 4 if this occurs. The metal plate 6 is additionally of sufficient thickness to enable it to act as a shield for the pipe 4 so as to stop or deflect any nails accidentally driven through the floorboard. In the figures shown, the notch 2 is cut to have a length corresponding to the length L of the element 1. This ensures a particularly good fit between the element 1 and the joist 3 and ensures the maximum support for any overlapping floorboard. Furthermore, since the metal plate only extends to the edges of element and thus the notch, no part of the element will interfere with any attempts to drive nails, etc, into the joist adjacent to the notch.

Figs. 3 and 4 show another embodiment of the invention in the form of a pipe element 10 comprising a moulded plastics body 11 and upper plate 12 and formed with two channels 13. This pipe element is particularly designed to be fitted in place over two pipes running side by side. These are accommodated in the channel 13. Further elements may be designed to cope with three or more pipes running side by side.

Fig. 5 shows a further embodiment of the invention in which a pipe retaining element 20 of otherwise identical construction to the element of Fig. 1 is provided with a U-shaped insert 21 which fits inside the element 20 and which is held in place by means of legs 22 which engage with slots 23 running along the width of the element. The insert 21 may be clipped in place or removed according to the diameter of the pipe which the element is intended to retain. Further inserts may be

provided to retain pipes of progressively smaller diameter.

Similar inserts may also be provided with the embodiment of Figs. 3 and 4. Alternatively, different configurations of the single and double pipe retaining elements may be provided having different shapes of internal channel. In the case of the double pipe retaining element, a number of configurations may be required to deal with the situations of identical pipes running side by side or pipes of different diameters running side by side. Of course, if inserts are used, a single double pipe retaining element can be used to retain any combination of pipes of different diameters. The convenience of these inserts will be readily understood. A plumber having to fit pipes of varying diameters around a site need only take with him one or two basic elements and a range of inserts to suit his purposes, in contrast possibly to as many as four or five different elements to suit the possibilities of one or two pipes and a plurality of thicknesses.