This invention relates to a system for fixing tiles to a roof structure, using metal tiling battens instead of timber tiling battens, as have been used hitherto.
The availability of timber roof tiling battens is affected by climatic conditions and diminishing resources of natural timber stocks to the extent that a substitute in the form of metal is the obvious solution to the ultimate scarcity problem of this very important component of roof tile cladding of domestic and other buildings.
Timber tiling battens are not normally regarded by the timber industry as regular constructional items and as such they are usually cut from the wastage section of trees after normal structural sections have been milled.
This fact alone affects the quality, available lengths and regularity of supply of timber battens and creates major problems for the roof tiling industry particularly in ensuring sufficient holding stocks to suit the building rate, the necessity of speedy turnover of stock before undue weathering has affected the quality and the obvious yard and on site wastage which must of course be recovered in the selling price to the consumer.
Distribution of job lots to building sites is costly due to bulkiness of pack sizes and weight.
Further, the variations in available lengths and quality of the timber causes on site wastage to be as high as 15% on the majority of projects. This also is a cost factor to be incurred by the consumer.
With the recent introduction of metal roof trusses in the domestic building industry, roofing companies and contractors are experiencing difficulties in the application of timber tiling battens to steel rafters, and, as a result the labor cost for this item has been increased.
Further, there have been recent changes in the building regulations concerning the security of timber batten connections to roof rafters, particularly in the designated high wind areas and as such traditional methods of securing timber tiling battens with standard nails is now suspect and specifications are being and will continue to provide for more proven systems of connection such as screwing, bolting strapping or other fasteners which, of course, will, if enforced, add considerably to the labor cost of application of timber battens in these areas.
As the spacing of roof rafters and trusses varies from 600mm to 900mm, different sizes of timber tiling battens need to be stocked and delivered according to the particular rafter spacings of the project.
The labor involved in application of timber tiling battens to a roof structure which is to be sarked with a waterproof membrane increases considerably and is thus a more costly item to the consumer. Furthermore, the traditional method of setting out tiling batten spacings on roof rafters by means of nails being partially driven into the top face of the rafter is not only a safety hazard to the contractor but causes damage to the sarking membrane during application by undue tearing which needs to be sealed to prevent water penetration.