Wood joints in structural (prefabricated) timber constructions: on-roof insulations, timber (frame) constructions, formworks, rafter and shifter attachments

Installation indoors or in dry areas of wet rooms

Outdoors without direct weathering

Advantages:

Surface-flush fixings and reduced wood cracking
- Countersunk head with milling ribs and notch (“CUT”) at screw tip, for close to the edge screwings
High load-bearing capacity
- Extended thread length and strong thread flanks ensure optimum wedging in wooden substrates
Power and energy saving
- Reduced screwing torque due to milling ribs at shaft and special sliding coating on the thread
Reduced wood-cracking
- Notch (“CUT”) at screw tip for close-to-the-edge-screwings
Maximum safety and high product quality
- Ensured by ETA-12/0280 and external independent testing institute

Processing information

Load-bearing, approval-relevant timber constructions always have to be calculated by structural engineer with ETA of applied screws
Design of fastening points/ overall construction must be based on the characteristic load values of screw type and installation specifications within ETA-12/0280
Fixing of thermal insulation must also comply with local applicable national regulations
Only countersunk head screws allowed for connecting wood-based materials to roof-mounted insulation systems
To further increase load-bearing capacity, countersunk washers acc. to ETA-12/0280 or flat washers according to DIN 440 may be used
For on-roof fastenings, 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/ centre distance: max. 1750 mm
Insulation thickness: min. 300 mm
Compressive insulation strength: min. 0.05 N/mm²

Advice

Applicable with or without pre-drilling (pre-drilling-Ø ≤ screw core-Ø)
Pre-drilling usually not necessary for screwing into softwoods (e.g. spruce, pine, fir)
When using hardwood, pre-drilling is recommended to prevent screw breaks
When using metal attachments (screw-head-side), pre-drilled hole in the metal part must be larger than thread-outer-Ø

Datasheets & Downloads

Language

Type

Art.No.

Approval/Assessment

ETA-12-0280 Timber Screws 11-2022 EN

18.11.2022

Verschillende toepassingsgebieden vereisen verschillende schroef- en draageigenschappen van een schroef. Opmerking: Voorboren wordt met name aanbevolen voor schroeven die zeer dicht bij de rand komen of om het risico op splijten te verminderen.

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