TR-13 – Intermediate Floor Junction

This metal web floor wall junction detail shows a proprietary timber intermediate floor supported from a rendered masonry cavity wall.

The drawing illustrates metal-web Ecojoists supported from the inner masonry leaf, together with the floor deck, acoustic insulation, ceiling lining, masonry joist hangers and external-wall construction. It demonstrates how cavity insulation, wall restraint, fire protection and airtightness should be maintained through the intermediate-floor zone.

A brick-faced version of this metal-web floor junction is also available. For broader structural requirements affecting floors and walls, consult Approved Document A.

Supporting notes cover:

• Specialist design of metal-web timber joists.
• Joist sizes, spacing, bearings and structural loading.
• Masonry joist hangers and built-in joist ends.
• Prohibition on cutting timber chords or metal webs.
• Wall restraint straps and associated noggings.
• Moisture-resistant tongue-and-groove flooring.
• Strongbacks, rim boards, blocking and trimming members.
• Acoustic mineral-wool insulation between joists.
• Fire-resistant plasterboard ceiling construction.
• Service routes through the open metal webs.
• Fire-stopping and cavity barriers.
• Airtightness at the wall and floor junction.
• Continuity of the external cavity insulation.
• Junction SAP reference E6 and the calculated PSI value shown on the drawing.

The customer receives one downloadable PDF construction drawing, prepared at a scale of 1:10 and formatted for an A3 sheet.

Joist depth, spacing, bearings, hangers, strongbacks, trimming members and connections must be confirmed by the floor manufacturer’s structural calculations and layout. Fire, acoustic and restraint requirements must also be coordinated with the project design and Building Regulations.