TR-18 – Verge Detail: Pitched Warm Roof

This pitched warm roof verge detail shows a typical junction between a pitched warm roof and the gable end of a rendered masonry cavity wall.

The drawing illustrates rigid roof insulation at rafter level, insulation between the final rafter and gable wall, roofing underlay, tile battens, cavity insulation and the external masonry construction. It demonstrates how a continuous insulated envelope should be maintained around the verge while preserving any required ventilation route above the insulation.

For a corresponding facing-brick construction, see our TB/18 warm-roof verge detail. Approved Document C provides the official guidance on resistance to moisture in roofs and walls.

Supporting notes cover:

• Structural design of roof rafters or trusses.
• Gable-wall restraint straps and solid noggings.
• Rigid insulation between and beneath the rafters.
• Insulation between the final rafter and masonry wall.
• Continuity between roof and cavity-wall insulation.
• Roof-level insulated cavity closers and cavity barriers.
• Vapour-control and airtightness membranes.
• Roofing underlay and supported battens.
• Proprietary mechanically fixed dry-verge systems.
• Traditional mortar-bedded verge alternatives.
• Mechanical fixing against wind uplift.
• Render stop beads and weatherproof sealing.
• Junction SAP reference E13 and the calculated PSI value shown on the drawing.

The customer receives one downloadable PDF construction detail, drawn at 1:10 and arranged to fit an A3 sheet.

Insulation thicknesses, ventilation, vapour control, roof restraint and verge construction must be coordinated with the structural design, U-value calculation, condensation-risk assessment and manufacturers’ installation requirements.