How does glulam perform in fire when exposed?

Exposed glulam performs predictably in fire, charring at 0.65 mm/min with a protective char layer insulating the residual section. For architectural applications where the glulam is exposed (no encapsulation), the beam must be oversized to maintain structural capacity after charring.

Exposed glulam performs predictably in fire, charring at 0.65 mm/min with a protective char layer insulating the residual section. For architectural applications where the glulam is exposed (no encapsulation), the beam must be oversized to maintain structural capacity after charring. For 60-minute fire resistance: add 46 mm to each exposed face (39 mm char + 7 mm zero-strength layer). A GL24h beam requiring 140 × 500 mm structurally would need 232 × 546 mm minimum for REI 60 with three-sided exposure. This oversizing is often architecturally acceptable as it enhances the visual presence of the beam.

Why this matters

This question relates to Glulam Beam Design: Aesthetic & Structural Possibilities, which covers the broader topic in detail. Understanding this specific aspect helps architects, builders, and timber dealers make informed specification decisions.

For full context and additional technical detail, see our comprehensive guide:

→ Glulam Beam Design: Aesthetic & Structural Possibilities

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About this answer

This answer is part of the PuurModulair Knowledge Base — comprehensive timber specification guidance for architects, builders, and dealers across the UK, EU, and Scandinavia.