Processing information
Please note maximum breaking torque for each thread-Ø in respective DoP / ETA
Screws with drill-tip are not intended for use with dowels
For wood with high tannin content, A4 stainless steel screws should be used (e.g. oak, acacia, larch, cedar, cassava, merbau, robinia, cumarú, etc.)
For Douglas fir wood: min. distance of screws to be increased by 50 % in fibre direction
Woods with density ≥ 500 kg/m³ (e.g. Bangkirai) should be pre-drilled with 0.6 - 0.8 x screw thread-Ø
For screw connections in load-bearing timber structures, installation specifications of ETA-12/0280 to be considered
Load-bearing, approval-relevant timber constructions to be calculated by structural engineer with ETA of applied screws
Fixing of thermal insulation must also comply with local applicable national regulations
Only countersunk head screws (Ø 6.0) allowed for connecting wood-based materials to roof-mounted insulation systems
To further increase load-bearing capacity, washers acc. to ETA-12/0280 may be used
For on-roof fastening, screws have to be driven into the rafter in one sequence through battens and thermal insulation material without pre-drilling (ETA-12/0280: A.1.4. installation provisions)
Rafter width: min. 60 mm
Screw/ center distance: max. 1750 mm
Insulation thickness: min. 300 mm / compressive insulation strength: min. 0.05 N/mm²
