INTRODUCTION
Some roofs are attached to the roof frame using concealed fixings. Examples include Klip-Lok, KingKlip or Speed Deck. These roofing systems do not have any penetrations (piercings or holes) in the roof sheet and when standing on the roof there are no screw heads to be seen. The roof sheet is clipped onto concealed fixings which in turn are fixed to the battens with standard screws. Thus, the total fixing capacity is defined by the total number (and type) of screws used to hold the concealed fixings to the battens.
CLAMPS
Clamps are available that are designed to attach to the roof sheet without piercing it. SunLock have our own, as they can supply load capacity ratings based on test data.
Kliplok 406 and 700
Trapezoidal Bracket
Longline
Use the correct clamp
Every roof sheet has a different geometry. The make and model of roof sheet must be identified prior to sourcing the correct clamps. If the wrong clamp is used it either won’t fit or will crush or tear the roof sheet as it is tightened up. SunLock however has a configurable clamp that fit most of the sizes, so you don’t have to worry about getting the wrong clamp.
Contact SunLock for advice on selecting the correct clamp for your roof sheet.
Use clamps as a 1:1 replacement for screws
When installing a SunLock flush-mount or tilt frame, use the SunLock installation manual to work out how many roof screws are required. Then, use the same number of clamps – i.e. one clamp replaces one roof screw.
Although some manufacturers can provide test results showing that clamps are stronger than a roof screw, these laboratory tests are conducted using ideal conditions such a new screw perfectly installed in a new timber purlin. In real life the condition of the battens and screws are not as good and therefore the clamps must be de-rated to the value shown in the SunLock manual for one roof screw fixing.
Locate the clamps directly over the concealed fixings
Concealed fixings can be located by either looking for a slight bump in the roof sheet or by gently pressing a boot down on the roof sheet whilst sliding the boot back and forth. The roof sheet has some give while the concealed fixing is stiff.
Never install a clamp in between two battens / purlins. The roof sheet is not a structural component and is not strong enough to transfer the extra load of the solar PV array sideways to the next batten. The roof sheet is only strong enough to withstand its own wind loads.
Join several clamps with a rail / channel
One clamp by itself can rock or move slightly under fluctuating wind loads. By bolting clamps to a rail or channel this rocking motion is eliminated.
These clamps attach to the crest of the roof (directly over the concealed fixing) and therefore transfer the wind loads directly into the concealed fixing, the screw and on to the batten.
TIPS
SunLock channel feet (SLCF2) are quick and easy to bolt to the clamps and attach to channel v2 (SLSCC3).
For Further information
For further information contact SunLock on 1300 655 554 or order@sunlock.com.au.