How do I detail timber cladding at windows and doors?

Window and door junctions are the most critical details for facade longevity. Key principles: install metal head flashings with minimum 10 mm stand-off from cladding face to prevent capillary action; slope sills at minimum 15° with drip groove on underside; maintain 10 mm minimum gap between cladding and frame for drainage and movement; seal end grain of cladding boards at all terminations; ensure the breather membrane is dressed into the window frame with appropriate tapes; and provide weep slots at sill level to drain any trapped moisture.

Window and door junctions are the most critical details for facade longevity. Key principles: install metal head flashings with minimum 10 mm stand-off from cladding face to prevent capillary action; slope sills at minimum 15° with drip groove on underside; maintain 10 mm minimum gap between cladding and frame for drainage and movement; seal end grain of cladding boards at all terminations; ensure the breather membrane is dressed into the window frame with appropriate tapes; and provide weep slots at sill level to drain any trapped moisture.

Why this matters

This question relates to Timber Facade Design: Weathering, Maintenance & Detailing, 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:

→ Timber Facade Design: Weathering, Maintenance & Detailing

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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.