The ULAMEX J-Gont Hook Handle is a fixed-height stainless steel roof hook designed specifically for mounting photovoltaic panels on slate and shingle (Gont/Schiefer) roofs. The distinctive J-shaped profile slides beneath the slate or wooden shingle course without disturbing the waterproof overlap pattern, providing a clean and structurally sound anchor point for PV mounting rails. Manufactured from H17 stainless steel (1.4016 / AISI 430), this ferritic stainless hook has a fixed 70 mm height, 30 mm width, 225 mm length and 4 mm thickness. Fastened with a Torx wood screw directly into the rafter beneath.
Technical Specifications
| Parameter | Value |
|---|---|
| Material | H17 stainless steel (1.4016 / AISI 430), ferritic |
| Height | 70 mm (fixed) |
| Width | 30 mm |
| Length | 225 mm |
| Thickness | 4 mm |
| Fastening | Torx wood screw (into rafter) |
| Finish | Natural stainless (mill finish) |
| Roof type | Slate, shingle, fibre-cement slate |
| Service life | 25+ years |
Installation Guide
Carefully lift or remove the slate/shingle at the planned hook position using a slate ripper tool to avoid cracking the material. Expose the rafter beneath and position the J-gont hook with the J-shaped head oriented to emerge between the slate courses. The 225 mm length ensures the hook base engages securely with the rafter while the head protrudes through the gap between overlapping slates. Pre-drill a pilot hole if the timber species requires it, then drive the Torx wood screw through the hook base plate into the rafter. The Torx drive delivers high torque transfer and resists cam-out, ensuring a tight, permanent connection. Slide the slate or shingle back into position over the hook body — the slim 30 mm width and J-profile allow the slate to sit flat without lifting. Attach the PV mounting rail to the fixed 70 mm hook head. Repeat at each hook position, typically spacing hooks every 800–1,200 mm along each rail line as specified by the structural load calculation.
Roof Compatibility
The J-gont hook is engineered for natural slate, fibre-cement slate and wooden shingle (Gont) roofs. These roofing types are characterised by thin, flat overlapping elements that require a hook profile thin enough to slip beneath the covering without lifting or breaking adjacent tiles. The fixed 70 mm height is designed for new-build roofs with consistent rafter depths. Common on heritage buildings, mountain architecture and traditional Northern European construction, slate and shingle roofs represent a significant segment of the roofing market in Germany, Switzerland, Austria, Belgium and the Nordic countries. The J-gont hook also works on fibre-cement roof slates (such as Eternit or Cembrit products), which share the same flat, overlapping laying pattern as natural slate. Maximum recommended rafter spacing: 80 cm. For roofs with varying rafter depths, consider the adjustable J-gont hook instead.
Material Properties — H17 Stainless Steel
H17 (1.4016 / AISI 430) is a ferritic chromium stainless steel with 16–18% chromium content, providing good atmospheric corrosion resistance and a tensile strength of approximately 450 MPa. For roof hook applications, H17 offers the ideal balance between corrosion protection and cost. Because the hook is concealed beneath the slate during normal service, it is not permanently exposed to standing water or direct UV radiation. The ferritic crystal structure provides superior resistance to stress corrosion cracking compared to austenitic grades — an important property in the temperature-cycling environment beneath roof coverings where condensation can form. H17 is magnetic, simplifying handling and positioning during installation on the roof.
Why Choose ULAMEX
ULAMEX has supplied structural steel and stainless steel components for over 35 years, holding EN 1090 certification for the execution of steel and aluminum structures. As a B2B wholesaler, we deliver roof hooks, PV profiles, clamps, fasteners and ballast systems from a single source — reducing procurement complexity and ensuring component compatibility. European delivery with competitive wholesale conditions for solar installers, distributors and EPC contractors.
Frequently Asked Questions
When should I use the fixed J-gont hook versus the adjustable version?
The fixed 70 mm J-gont hook is the right choice for new-build roofs and well-maintained structures where all rafters have a consistent depth. If your roof is older, renovated or has rafter depth variations exceeding 5–10 mm, the adjustable J-gont hook provides stepless height tuning to create a level mounting rail plane.
Will the hook damage natural slate tiles during installation?
Natural slate is a brittle material that can crack if handled roughly. Use a professional slate ripper tool to lift or remove slates at hook positions. The J-gont hook’s slim 30 mm width and 4 mm thickness are designed to minimise interference with the slate — the slate should sit flat over the hook body without modification. Handle slates carefully and avoid forcing them back into position.
How does the J-gont hook maintain waterproofing on a slate roof?
The J-shaped hook head emerges between two overlapping slate courses. The upper slate acts as a natural water deflector, channelling rainwater over the hook and down the roof surface. The hook body runs along the rafter beneath the slate, protected from direct water exposure. This overlap-based waterproofing principle is the same mechanism that keeps the entire slate roof watertight.