Design CLT to Eurocode 5

A full set of CLT calculators for floor, fire, connections and shear wall design in Europe to Eurocode 5 (EN 1995-1-1), with real product data from CLT and fastener suppliers including Rothoblaas, Eurotec, SPAX and Würth built into every calculation. Specify actual panel and connector performance rather than working from assumptions, across national annexes. Try the calculators to start specifying certified CLT solutions with confidence.

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Standard: EN 1995-1-1:2004 (Eurocode 5), fire per ÖNORM B EN 1995-1-2:2011 and draft prEN 1995-1-2:2023
National annexes: Austrian National Annex explicitly named for fire design

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CLT Design in Europe is transforming the skyline, yet for many structural engineers, the path to a compliant mass timber design is filled with technical roadblocks. Despite its prevalence, specialized CLT design software for Eurocode 5 is rarely taught at the university level, leaving a significant knowledge gap in the local industry.

Designing with the primary European timber code, EN 1995-1-1, presents a unique challenge: while the code provides the foundation, managing the complex layer-by-layer verification for CLT requires navigating national annexes and diverse manufacturer-specific data. This complexity forces engineers to use a verified CLT calculator to manually synthesize first principles with code-specific factors like kmod, ksys, and Ym.

The engineer's guide

CLT Design · Eurocode 5

The European Engineering Platform for CLT Design
Design of CLT Floors
Design of CLT Fire
Design of CLT Connections
Design of CLT Shear Walls

The European Engineering Platform for CLT Design

Checks both Ultimate Limit State (ULS) and Serviceability Limit State (SLS) criteria:

Bending Capacity (fm,Rd): Checks the moment capacity of the longitudinal layers.
Shear Capacity (fv,Rd): Checks longitudinal shear strength.
Rolling Shear (fr,k): The “Achilles Heel” of CLT — rigorously checks shear stress in the cross-layers (weak rolling shear plane) which often governs the design of short spans.
Deflection (winst, wfin): Calculates instantaneous and long-term creep deflection (kdef).
Vibration Analysis: Checks natural frequency (f1 > 8Hz) and stiffness criteria for residential and office comfort.

Design of CLT Floors

Same Gamma Method / Extended Gamma Method / Shear Analogy Method structure and vibration design content as ANZ CLT page (see earlier entry) — content is essentially identical across regions for this section.

Design of CLT Fire

Advanced CLT Fire Engineering — structural fire design is a critical component of any Eurocode-based structural verification and performance-based fire engineering solution. Supports ÖNORM B EN 1995-1-2:2011 (Austrian National Annex) through prEN 1995-1-2:2023 (2nd Generation Eurocode). Supports standard fire curve based on EN 1363-1 testing or project-specific fire test data.

Precision Charring & Bond-Line Integrity — defines basic charring rate β₀ based on timber density and moisture content; platform applies Eurocode modification factors to determine notional charring rates βₙ. 2nd Generation Eurocode module models bond-line integrity and delamination effects.

Automated Factor Analysis — automates calculation of Eurocode charring and protection factors including gaps, protection layers, layer fall-off behaviour. “No Black Box” approach: code-specific defaults or manual inputs from manufacturer fire tests.

Design of CLT Connections

Moving Beyond Simplified Connection Design— Advanced Yield Modeling (Eurocode Johansen Yield Models); ETA Integration (supplier-specific European Technical Assessments).
Simplified Screw & Joint Design— Preconfigured Joint Types (Half Laps, Splines, Butt Joints); Steel-to-CLT modules.
“Global-Local” Connection Library— Universal Fastener Selection: ESSVE,Eurotec, Klimas, Rocket/Vynex, Rothoblaas, Schmid Schrauben, Sihga, SPAX, Würth, or Pitzl. Verified Compatibility with European CLT panels: KLH, Kalvasta Timber, Binderholz, Södra, MTT, Theurl, or Xlam Dolomiti.

Design of CLT Shear Walls

Identical content to ANZ CLT page (ProHolz vol 1 Clause 5.8, FP Innovation Clause 3.8, five wall connection methods — Casagrande, Wallner-Novak, Tomasi, Pei, Reynolds) — see earlier entry for full text.

Frequently asked questions

CLT Design · Eurocode 5

Does this calculator handle Fire Design?

For this specific module, we focus on "Cold" (Ambient) design. However, CLT generally performs well in fire due to the "Charring Rate" (β0 approx 0.65 mm/min). We recommend checking our standalone CLT Floor Fire Calculator for fire limit states.

Can I define custom layups?

Yes. You can select standard layups (e.g., 100mm 3-ply, 140mm 5-ply) or define a custom buildup layer-by-layer to match a specific manufacturer (e.g., Sodra, KLH, Binderholz).

What about Point Loads?

The current version analyzes Uniformly Distributed Loads (UDL) typical for floor joist design. For concentrated point loads, local punching shear checks may be required separately.