How to tell if a wall is load-bearing
Treat every wall as load-bearing until a structural engineer confirms otherwise. The reliable signs: walls that run perpendicular to the floor joists above (visible if you lift floorboards on the floor above), walls that sit directly above another wall on the floor below (load path continuity), walls that carry a beam or RSJ on top, and walls in the centre of the property running front-to-back on Victorian/Edwardian terraces (the classic 'spine wall'). Walls that often turn out to be load-bearing despite appearances: cupboard divider walls in chimney-breast alcoves; the wall between the front reception and middle reception in a London terrace; any wall directly under a bathroom or kitchen on the floor above. We engage a chartered structural engineer (MIStructE or MICE) at survey stage. The engineer carries out a load take-down, sizes the new beam and signs off the calculations — typically £450–£900 included in our fixed-scope quote.
Beam selection: RSJ vs UC vs Flitch
The structural engineer specifies one of three beam types based on span, load and ceiling depth available. Rolled Steel Joist (RSJ) — the classic I-section, used for most domestic openings up to about 4m span; available in standard sizes (152x89, 203x102, 254x102 etc.) at £35–£75/m supplied. Universal Column (UC) — squarer cross-section, used where stiffness matters or ceiling depth is restricted; common sizes 152x152, 203x203. Flitch beam — timber + steel plate sandwich, used where a deeper beam is needed but a full steel section would be visually intrusive; more labour-intensive but flush with timber ceilings. For wide openings (>5m), a twin-RSJ or single deep UC is required, with a structural post mid-span if the calcs demand. We supply, hoist and install all beam types — including overnight craning where access is restricted.
Building regulations and fire protection
Wall removal triggers Part A (Structure) of the Building Regulations. The structural engineer's calcs are submitted as part of a Full Plans application; the local authority or Approved Inspector reviews and issues approval. Building control inspects at three stages: padstone preparation, beam install and pre-plaster (with fire protection in place). Fire protection is required under Part B: any new steel beam in a domestic property must achieve 30 minutes of fire resistance. This is achieved by encasing the beam in two layers of pink fire-rated plasterboard with all joints staggered and taped (the cheapest option) or with intumescent paint (more expensive but maintains slimmer profile). Steel beams left exposed without protection will fail building control. Builderr always fire-protects to spec and provides the completion certificate at handover.
Party wall implications for terraced houses
Many London load-bearing walls bear onto a party wall. Removing such a wall means the new beam's padstone sits in the party wall — triggering a Party Structure Notice under section 2 of the Party Wall Act 1996. We serve the notice at design completion, giving the neighbour 14 days to consent or dissent. Consent in writing: work proceeds with a schedule of condition. Dissent or no response: party wall surveyors appointed, Award prepared (typically £700–£1,500 agreed surveyor, £1,200–£2,500 separate surveyors). The Award sets out working method, hours and protection measures, and creates a permanent record protecting both parties. Builderr serves notices as part of standard project management; surveyor fees are separate and transparent.
The install sequence
Day 1: Site protection — dust sheets, floor protection, temporary stair barrier. Mark out the opening; check services route (water, gas, electrics, central heating pipework). Day 2: Install temporary needling support (Acrow props with cross-needles through the wall above the planned opening, taking the load while the new beam is installed). Engineer inspects propping before work proceeds. Day 3–4: Cut out the wall below the props in controlled sections; prepare padstones at each end (typically engineered concrete or precast). Day 4–5: Hoist beam into position, bed onto padstones with non-shrink grout; engineer signs off install. Day 5–7: Remove propping, infill above beam, prep for fire protection. Day 8–10: Fire-protect (plasterboard or intumescent), plaster, repair any disturbed areas, decoration. Day 10: Building control sign-off. Day 11: Final clean, completion certificate.
