CLT (Cross-Laminated Timber) in South Africa: Adoption Guide

Cross-laminated timber transforms timber from a stick-frame material into a primary structural system. Mid-rise CLT buildings have moved from architectural curiosity to mainstream specification — though South African fire regulations still impose meaningful constraints.

What CLT is

Solid timber panels of glued, perpendicularly laminated boards. Typically 3, 5, 7, or 9 layers. Standard panel sizes up to 16m × 3m, thicknesses 80–400mm.

Advantages

• Embodied carbon roughly 50% of equivalent concrete
• Off-site fabrication (factory-cut to CNC tolerance)
• Fast erection (1 storey per week typical)
• Excellent acoustic performance vs lightweight timber framing
• Visible timber finish if desired

UK constraints

Fire regulations (post-Grenfell)

SANS 10400-T (Fire protection) restricts combustible materials in external walls of buildings over 18m. CLT structural elements within external walls must be fire-protected. Encapsulation typically required.

Insurance

Insurer appetite for tall CLT remains limited. Some lenders restrict CLT residential loans above 4 storeys.

Acoustic detailing

CLT alone doesn't meet Part E requirements between flats. Resilient flooring, suspended ceilings, and specialist detailing required.

Typical applications

• Schools and education buildings (often left exposed)
• Low-rise residential (up to 3–4 storeys typical)
• Mid-rise office (encapsulated)
• Hybrid systems (CLT floors with concrete cores)

Spans and depths

• 3.5m residential span: 100–120mm CLT
• 5m office span: 160–200mm CLT
• 7m+ spans: typically beam-supported or glulam ribs

Cost

• CLT supply: R11,000–R18,000 per m³
• Installed structural cost per m² GIFA: R5,600–R8,400 (versus concrete frame at R5,200–R7,200)
• Premium recovered through programme savings and Agrément South Africa / CSIREAM credits

MCFAR designs CLT schemes alongside conventional structural systems.

Frequently Asked Questions