Identifying a load-bearing wall
Walls running perpendicular to floor joists are usually load-bearing. Walls under a structural element above (chimney, parallel wall on upper floor) are load-bearing. Solid masonry walls in older properties are more often load-bearing than studwork. Final confirmation needs an engineer's site visit — never assume from drawings alone. Cost of misidentifying: collapse or settlement, structural insurance claim, possibly six-figure remediation.
Steel beam design and installation
Structural engineer calculates load (dead + imposed + safety factor), specifies beam (typical 152x152 UC for short spans, 203x203 UC for longer, 254x254 UB or larger for double-storey openings). Padstones at each end transfer load to existing masonry — typically engineering brick or precast concrete pad. Installation: build temporary support (Acrow props or strongboys), break out wall above beam line, install steel on padstones, complete temporary load transfer, demolish remainder below beam, fire-protect steel with intumescent paint or 30/60min boarding to Approved Document B, plaster and decorate.
Building control and party wall
Building Regulations Approved Document A requires structural design (engineer's calcs and detail drawings) and inspection at key stages — typically pad install, beam install, fire protection. Submit building notice (£250–£500 in London) or full plans (£350–£700). If the wall is on a party line, Party Wall etc. Act 1996 Section 2(2)(a) applies — minimum 2 months notice, surveyor fees £1,200–£2,800 if neighbour appoints. Allow 4–8 weeks for party wall award before any cutting starts.
