SECT
| V1 | INSTALLATION MANUAL | 202102
11
SCHLETTER SOLAR GMBH | SUBJECT TO CHANGES
4. INSTALLATION USING ROOF SCREWS
SECT can be installed using roof screws that fix into purlins. Use the product code SPCF01
(SECT Channel Foot 01), to suit standard 14g roof screws.
The channel foot is supplied with an EPDM mat fixed to the base. The EPDM mat prevents
water ingress. The leak path is the annular gap between the roof sheet and the roof screw. This
is sealed by the thick EPDM washer located between the L-foot and the roof sheet. As the roof
screw is tightened the base of the channel foot presses down on the EPDM, causing the EPDM
to bulge inwards and press tightly around the roof screw, thus creating the waterproof seal.
The EPDM mat also provides a level of separation from the roof sheet, and corrosion protection for
the roof sheet. According to the BlueScope technical bulletin CTB-12 (Rev 3, November 2003) on
dissimilar metals, aluminium accessories are compatible with all common roofing materials,
including galvanized iron, Zincalume and Colorbond. Therefore, the aluminium channel foot is
permitted to directly contact the roof sheet. However, SECT recommends the use of the EPDM mat.
Other considerations:
Roof screws are not supplied. SECT recommends 14g fasteners (to replace the typical 12g roof
screw) with a Class 4 anti-corrosion coating, as described in ISO 9223-2012 and AS 4312-2008.
Channel should be extended past the last module frame to overlap the next available purlin.
Always install channel feet on the roof crest, not in the pan. This eliminates the majority of
the risk of water ingress.
Timber purlins should be pre-drilled, especially old hardwood that is prone to splitting.
The roof screw should be tightened in accordance with the installation manual for the roof
sheet. The roof screw should not be over tightened – the roof sheet should not be
deformed or crushed.
The fixing capacity of the channel foot is limited by either the roof screw or purlin it is
screwed into. The channel foot itself is not the limiting factor. Typically, the fixing capacity
is in the range of 1-2 kN.
SPCF01 with EPDM on the base
