TR-04 – Trench Fill Foundation, Cavity Wall and Suspended Timber Floor

This detailed drawing shows a typical junction between a rendered masonry cavity wall, trench-fill foundation and insulated suspended timber ground floor.

The drawing illustrates the timber floor joists, moisture-resistant tongue-and-groove flooring, insulation between the joists, perimeter insulation, ventilated subfloor void, concrete oversite, hardcore and damp-proof/basic radon barrier. It also shows how insulation should be fitted between the wall and joist ends to limit heat loss through the perimeter junction.

Supporting notes cover:

• Typical trench-fill foundation requirements.
• Suspended timber floor construction.
• Timber-joist support and structural design.
• Insulation between and around the floor joists.
• Subfloor ventilation and airbrick provision.
• Concrete oversite and ground preparation.
• Damp-proof and radon-barrier installation.
• Typical rendered cavity-wall construction.
• Wall ties, mortar and cavity control.
• Typical thermal-performance requirements.

The customer receives one downloadable PDF construction drawing, drawn at 1:10 and laid out for an A3 sheet.

This is a generic construction detail that must be adapted to the individual building. Joist sizes, spans, bearings and restraint should be confirmed by structural design.

Foundation depth, subfloor ventilation, radon protection and material specifications must be verified against the site conditions and Building Control requirements.