Introduction
Fast Flex Fixings offer the ease of use of a nail but the fixing capabilities of a screw and plug. They are available in two diameters - 6mm and 8mm - and a range of lengths from 50mm. When fixing timber to aircrete (AAC) blocks, using the 8mm diameter Fast Flex, there is generally no need to pre drill.
Fast Flex may also be used for fixing into hard materials. A small pilot hole may be drilled through the timber and into the brickwork or concrete behind, the Fast Flex 6mm is then simply driven home (Fig. 1).
Because of their design there is minimal finishing required once they are driven home. The Grade 304 Stainless Steel ensures that there is no unsightly staining or streaking of surface finishes, and they are not affected by any aggressive timber treatments.
Performance Requirements
Loading requirements to resist the wind suction based on CP3, Chapter V, Part 2, 1972, are given in the tables on Information Sheets TBF1 & TBF2, along with the minimum penetration depths, timber thickness and spacing guidance.
Testing of Fast Flexs is possible using a lightweight test unit to ensure that the correct tensile loading is achieved.
Fixing Details
Fast Flex fixings can be used to fix battens, skirting, dado rails or door frames on to aircrete blocks (Fig. 2). They may be painted directly without fear of staining.
Fast Flex are also to be recommended when fixing through insulation materials. They offer a ‘stand-off’ fixing (Fig. 3) that will not crush the insulant even if they are over hit; and being stainless steel they may be used externally at will offering a good method of increasing thermal insulation on solid walls.
Battens for vertical tiling may be fixed either directly to the bricks/blocks or through the insulation material.
Generally the batten thickness will need to be a minimum of 25mm, although 19mm can be used in special circumstances. This not only ensures a good ‘pull-through’ value at the batten/fixing connection, but also allows an ‘improved’ nail to be used to additionally fix into the batten.
The fixing embedment into the brick, block or concrete will depend on the strength of the material, the wind loading and the weight to be supported. As a rule of thumb, concrete requires 30mm, brick 50-70mm and aircrete 70mm+. Reference should be made to Information Sheets TBF1 & 2, and the use of a load test unit should be considered.
The potential uses for this product have only just begun. The diagrams throughout this publication may start to widen the horizon (Fig. 4).
There are a number of standard details that have been produced to allow Fast Flex fixings to be used in many structural situations. Full copies of these details are freely available, and an example is shown here.
Fast Flexs can be used in many unique and fascinating ways. They may be driven into the bottom of posts to fix them securely into a poured concrete base. Their design allows them to be placed very close to edges without danger of splitting the timber (Fig. 5).
When fixing timber posts for gates or fences to brickwork the Fast Flex offers an easy solution. A 5-6mm pilot hole is drilled through the post and into the masonry whilst holding the post securely up against the wall, and then hammering the Fast Flex straight into the hole. Because they are stainless steel there is no finishing requirement to resist any future possible corrosion (Fig. 6).
Fast Flex may also be used to fix softwood noggins or rails into timber frames without splitting the timber or requiring any drilling (Fig. 7).
Door frames can be similarly fitted to aircrete blocks by staggering the fixings up its length without danger of splitting the blocks as can occur with expansion type fixings (Fig. 8).
Part of a standard detail drawing showing how to fix a ceiling joist back to a bowing wall. The full details consist of: a title heading, an indicative drawing, and a full method statement. Any standard specification requirements are also included.
