RTF-01 – Trench Foundation with Beam and Block Floor

This timber frame trench foundation detail shows a typical trench-fill foundation supporting a rendered external wall above an insulated suspended beam and block floor. It also illustrates an insulated suspended beam and block ground floor. The detail covers the foundation, ventilated subfloor void, damp-proofing, insulation and external ground-level junction. It also shows the relationship between the wall, floor membrane and airtightness layers. The drawing provides useful construction information for Building Regulations applications, working drawings and site reference.

For a closely related junction, see our RTF-02 ground-bearing slab detail. Approved Document A provides official guidance on structural elements, including foundations, walls, floors and roofs.