Design ESSVE Screws to Eurocode 5

ESSVE has supplied the Nordic fastening market for over 50 years, and its ESSVE TIMBR TECH range brings a premium line of timber fasteners, all covered by European Technical Assessments, to mass timber design. The EU screw range is assessed under two ETAs: ETA-23/0747, reissued 30 September 2025, covering the ET-T, HF(HEX), W(WAF) and ESSDRIVE screws, and ETA-22/0789, issued 13 March 2023, covering the CY-FT, C-PT, H-PT and H-FT screws. Both are issued under EAD 130118-01-0603 for design to Eurocode 5.

The EU integration covers 11 screw families across the two assessments, presented together and grouped by certificate.
ETA-23/0747 (7 families)

• ESSDRIVE, countersunk head, partial thread: CorrSeal (6 and 8 mm, 60 to 300 mm) and electroplated zinc (6 mm, 40 to 150 mm).
• ET-T, cylindrical head, double thread, CorrSeal (6.5 and 8.2 mm, 65 to 330 mm).
• HF (HEX), hexagon head with flange, partial thread, CorrSeal (6, 8 and 10 mm, 50 to 240 mm).
• W (WAF), washer/wafer head, partial thread: stainless steel A4 (6 to 10 mm, 70 to 150 mm), CorrSeal (6 to 10 mm, 40 to 320 mm) and electroplated zinc (6 to 10 mm, 50 to 320 mm).

ETA-22/0789 (4 families)

• CY-FT, cylindrical head, full thread, yellow zinc plated (8 and 10 mm, 160 to 1000 mm).
• C-PT, countersunk head, partial thread, yellow zinc plated (8, 10 and 12 mm, 120 to 480 mm).
• H-PT, hexagon head, partial thread, bright zinc plated (8 and 10 mm, 80 to 200 mm).
• H-FT, hexagon head, full thread, bright zinc plated (12 mm, 60 to 220 mm).

Across both assessments the range runs in hardened carbon steel (CorrSeal, electroplated, yellow and bright zinc) and austenitic stainless A4 (SAE 316), in diameters from 6 to 12 mm, lengths from 40 to 1000 mm, and service classes SC1 to SC3.

At a glance, the ESSVE families support:

• Solid timber, glulam, CLT (face and edge fixing), and LVL.
• Timber-to-steel connections, including the H-PT hex screw specified for steel plates and connectors.
• Angled insertion.
• Reinforcement, using the fully threaded families.
• Service Class 3 and exposed conditions, via the CorrSeal coating and the stainless A4 wafer head.

• Reinforcement in all three modes. ETA-22/0789 sets out compression perpendicular to grain at supports, tension perpendicular to grain at notches, openings and transverse connections, and shear reinforcement with fully threaded screws (d ≥ 8 mm) inclined at 45 degrees; ETA-23/0747 adds tension and compression reinforcement perpendicular to grain.
• Compression screws checked against buckling, not just withdrawal. For fully threaded screws in compression, the assessment gives an ideal elastic buckling load on the surrounding timber (a buckling-on-elastic-foundation verification with a reduction factor), so a compression reinforcement screw is limited by buckling as well as by pull-out.
• Full-thread reach to 1000 mm. The CY-FT cylindrical full-thread screw extends to 10 × 1000 mm, giving long single-screw embedment for thick build-ups and perpendicular-to-grain reinforcement.
• Double-thread ET-T. Two thread pitches generate a draw-together clamping action beneath a discreet cylindrical head, in 6.5 and 8.2 mm up to 330 mm.
• Two routes to Service Class 3. The CorrSeal zinc-based coating (minimum 23 µm) and the austenitic stainless A4 (SAE 316) wafer head are both assessed for Service Classes 1 to 3, for coastal and industrial exposure.

All ESSVE screws are available in:

• the Screw module;
• the connection detail calculators: panel-to-panel (half-lap, spline and butt joint), slab-to-wall, wall-to-wall, floor-to-wall;
• the rib-deck calculator, for flexible connection design to Eurocode 5.

The fully threaded and reinforcement-marked families (the ESSDRIVE, ET-T, HF and W(WAF) screws under ETA-23/0747, and the CY-FT and H-FT screws under ETA-22/0789) additionally appear in the reinforcement connection details: beam notch, beam penetration, and beam compression perpendicular to grain.

Design follows EN 1995-1-1, with axially loaded screws verified to §8.7.2. The withdrawal capacity of clause 8.7.2(4) applies to screws with an inner-to-outer thread ratio between 0.6 and 0.75, which the ESSVE screws meet, and §8.7.2(1)P lists buckling under compression among the failure modes to consider, which the assessment quantifies. Both the 2004 and 2025 editions of Eurocode 5 are supported. Both assessments are CE-marked under Regulation. The same product data is used for design in the AUS and NZ markets in accordance with the applicable design standards there.