GB2141757A - Roof space fire-break - Google Patents

Abstract

A roof space fire-break, adapted to fit over one or more upstanding walls (1) separating two adjacent roof zones, comprises a succession of plates (4, 5, 6) of non-combustible material each having two skirts (7) to extend downwardly alongside the walls. The skirts are jogged so that successive plate skirts may overlap. Spaced non-combustible battens are provided externally of the plates, from which tiles may be hung, and non-combustible blocks extend between the battens to prevent communication along the length of the space there between. <IMAGE>

Description

SPECIFICATION Roof space fire-break The present invention relates to a fire-break for roof spaces, and more particularly for roofs which are continuous over a boundary wall, eg. in semidetached houses and terraces.

It was at one time common to extend boundary walls between adjacent houses of a terrace above the roof line. The main roof beams could then be supported by the boundary wall on each side.

Clearly, this arrangement prevented fire spreading from one attic or roof space to the next.

However, with the advent of pre-assembled trusses, and the decline in the building of chimney stacks, the situation has changed for the worse. The usual method of constructing buildings now means that the boundary wall, which is either a single wall or a double wall separated by a cavity, is built up either level with or below the roof line. The readyassembled trusses to form the roof are then positioned with the end ones close to, but not in contact with, the party wall. Roofing felt or bitumastic covering is spread over the skeletal roof and held down by wooden battens which serve also to hang tiles from. The spacing of the battens is accordingly dependant upon the size of tile used.

The word tile is used herein and throughout the specification to indicate not only tiles but also slates or any other roof covering of that type.

The above method leads to certain disadvantages in the fire-proofing between adjacent roof spaces. If the battens are laid across the gap they may, being wooden, burn and carry a fire across that way.

Smoke and flames may pass along the spaces between the battens. There have been attempts to cure this disadvantage by filling the spaces with concrete or cement. However this is not entirely satisfactory since the cement is heavy and it cannot be guaranteed to fill the space. Another problem is that the party wall cannot be finished to exactly the same pitch as the roof, nor can it be given a smooth finish level with the line of the roof. Again, smoke and flames may pass through the gaps left. Furthermore, it is well known that once a building has been completed, it settles. If the party wall settles more than the rest of the house, any gaps intercommunicating the two roof spaces are increased in size.

If the building settles more than the party wall, a ridge forms in the roof along the line of the party wall. In bad cases, this may cause tiles to crack and possibly allow water in.

It is an object of the present invention to overcome the above difficulties and provide a simple effective device for discouraging fire from spreading from one roof space to another.

According to the present invention there is provided a roof space fire-break adapted to fit over one or more upstanding walls separating two adjacent roof zones, the fire-break comprising a plate of non-combustible material having one or more skirts adapted, in use, to extend downwardly alongside the wall or walls.

Preferably, there are provided externally of the plate a plurality of spaced non-combustible batten means from which tiles may be hung, and noncombustible block means adapted to extend between the batten means to prevent communication along the length of the space therebetween.

The non-combustible material may be galvanised or other protected iron or steel.

The batten means may be L-angle strips so dimensioned as to extend from the plate to a distance similar to that which wooden hanging battens extend from the remainder of the roof. The L-angle strips may be apertured for ease of fixing to trusses of the roof.

The non-combustible block means may be elongate metal strips bent at substantially their middle portion. They may be sprung into place with the apex formed at the bend contacting one batten means and the two ends of the block contacting an adjacent one.

The plate may have two skirts. The skirts may be fixed at a predetermined spacing. Alternatively, the plate may have one or more, preferably two, adjustably fixed skirts. These may be adjustable on bolts in slots or in some other manner, so that they may be moved closer one to another.

The plate may comprise a plurality of sections each overlapping the adjacent one or ones. At points of overlap, the skirt or skirts of one of the sections may be joggled to co-operate with the skirt of the overlapping section in a substantially fire-proof manner.

The skirts may be fixed to the plate by welding or rivetting along substantially its entire length. At points of overlap, the skirt or skirts may not be joined to the plate and a gap may be left which is dimensioned to accommodate the overlapping section.

An embodiment of the invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a portion of a roof space fire-break embodying the invention; Figure 2 shows a roof space fire-break embodying the invention in separated condition and viewed from the interior of the house; and Figure 3 shows a typical roof structure to which the roof space fire-break embodying the invention may be applied.

Referring now to the drawings, and more particularly to Figure 3 thereof, there is shown a division between two roof zones. These zones may be the two attics of a pair of semi-detached houses, two attics of a row of terraced houses, or merely a break in the roof of a single long building. In the latter case, the dividing wall may be provided with fire proof doors. The drawing shows a cavity wall 1 as the separating wall. On each side of this wall the skeleton of the roof is made up of pre-assembled trusses 2.

As shown in Figure 2, a metallic plate is divided into three sections, atop one 4, a middle one 5, and a lower one 6. There could, of course be provided either more or less sections depending on the size of the individual sections and the size of the roof in question. To each plate section is attached, in this case by welding along an angled flange, two skirts 7.

The skirts of the bottom section 6 are angled at their lower end to co-operate with a flat base of the roof zone. The middle section is adapted to overlap the bottom section and accordingly the flange 8 extends only part way along the skirts. Beyond this point the skirt is separated from the section to provide a gap to accommodate the lower section. Also at this point the skirts of the middle section are joggled to extend adjacent to a portion of the skirts of the lower plate section. Similarly, the upper plate section 4 is adapted to overlap the middle plate section 5.

Therefore, again, the flange 8 does not extend the full length of the skirts which are similarly joggled.

Again, in this case, the skirts of the top plate section are angled at their upper ends to co-operate with the skirts of the top plate section on the other side of the roof.

To use the device, the plate sections are placed, starting with the lower and moving upwardly, over the party wall 1. The skirts extend into the gap between the party wall 1 and the end truss 2. In another embodiment, not illustrated, the skirts may be adjustable by such means as bolts in slots. In such a case, the skirts could be adjusted so that they are in close contact with the party walls. The outer edge of each plate section is adapted to rest on or be attached to the end truss of each roof space.

On the outer side of the plate sections are laid L-shaped metal battens 10. These may be nailed through apertures 11 to a truss. As can be seen, they project from the metal plate section 4 to a similar distance as do wooden battens 12 project from the roofing felt 13. They are placed to line up with the wooden battens 12 so as to continue the row of tiles in a straight line. It is for this reason that it is difficult to attach these metals battens permanently to the plate sections. The building trade is, in general, not an exact science. The sizes of tiles may vary, and it may be necessary to vary the gauge, ie. the distance between battens, so as to gain or lose space and enable the roof to be completed without a half row of tiles.

To prevent fire spreading between the metal battens 10 the spaces could be filled with glassfibre filler. Alternatively, and as shown in the preferred embodiment, a metal block 14 is placed between each two adjacent battens. The block is an elongate strip of metal bent in its centre. It has cut outs 15 of the thickness of the metal batten so that it fits exactly between the plate section 4 and the tiles which cover the roof. To use the metal blocks, a suitable position is chosen where the blocks will not interfere with the attachment means of the tiles to be affixed in that row. It is then flexed slightly and inserted so that the cut outs 15 co-operate with a lower metal batten 10.

It is released and its springiness causes the apex to contact the metal batten above. This resilience allows the metal blocks to compensate for any changes in gauge for each standard range of tiles.

For example, the standard tile requires a gauge of between 101/4"and 101/2".

A preferred size of the plate sections is six feet or two metres. In order to accommodate variations in height of roofs, the overlap between various of the plate sections can be varied.

Claims (8)

1. A roof space fire-break adapted to fit over one or more upstanding walls separating two adjacent roof zones and comprising a plate of noncombustible material having one or more skirts adapted, in use, to extend downwardly alongside the wall or walls.

2. Afire-break according to Claim 1 and in which there are provided externally of the plate a plurality of spaced non-combustible battens from which tiles may be hung, and non-combustible blocks adapted to extend between the battens to prevent communication along the length of the space there between.

3. A fire-break according to Claim 1 or Claim 2 and in which the non-combustible material comprises galvanised iron or steel.

4. A fire-break according to Claim 2 or Claim 3 and in which the battens comprise angle strips so dimensioned as to extend from the plate to a distance similar to that which wooden hanging battens extend from the remainder of the roof.

5. A fire-break according to any of Claims 2 to 4 in which the non-combustibie blocks comprise elongate metal strips bent at substantially their middle portion.

6. A fire-break according to Claim 5 and in which the blocks are sprung into place with the apex formed at the bend contacting one batten and the two ends of the block contacting an adjacent one.

7. A fire-break according to any of the preceding Claims and in which the skirts of the plate are joggled to co-operate with the adjacent skirts of the next plate and a succession of such plates comprise a plurality of sections of an overall substantially fire-proof plate zone fitting over and extending along an upstanding wall separating two adjacent roof zones.

8. A roof space fire-break substantially as described herein with reference to and as illustrated in the accompanying drawings.