What is an RSJ? Steel beams explained for homeowners
RSJ, UB, UC, PFC, flitch beam — what the terms mean, which steel beam is used where, and what an RSJ costs supplied and fitted in 2026.
Service
Lintel installation & replacement
Cracking above a window or door, a dropped brick arch or a rotten timber lintel are common signs that a lintel has failed. We prop the wall above, remove the old lintel and install a correctly sized steel or concrete lintel, then rebuild and repoint the brickwork.
We also fit new lintels when windows and doors are widened or new openings are formed.
What’s included
- Diagnosis of cracking above openings
- Replacement of failed timber, concrete and steel lintels
- New lintels for widened windows and doors
- Cavity trays and weep vents where needed
- Brickwork rebuilt and repointed to match
- Internal making good
Worth knowing before you book anyone
Hidden timber lintels
Many older homes have timber lintels behind the inner leaf of the wall or over bay windows. They can rot unseen, so it is worth checking them when windows are replaced.
Building control
Lintel replacement is structural work. We confirm at survey whether building control need to be notified for your job.
Lintel installation & replacement: your questions answered
What causes cracks above windows and doors?
Most often a failed or undersized lintel, a rusting steel lintel in an older house, or movement in the brickwork. Stepped cracks running up from the corners of an opening are a classic sign.
Can a lintel be replaced without removing the window?
Often, yes. The wall above is propped and the lintel replaced from outside, although sometimes the frame has to come out.
Related guides
Building regulations for removing a wall: approval, inspections and certificates
Removing a load-bearing wall needs Building Regulations approval. The routes, the inspections and why the certificate matters when you sell.
Where we do this
Lintel installation & replacement across Knutsford, Wilmslow, Macclesfield, Altrincham, Sale, Stockport, Didsbury & South Manchester, Stretford & Urmston, Warrington, Northwich, Chester, Crewe & Nantwich, Congleton.
Need lintel installation & replacement?
Send photos or your engineer's drawings for a same-day budget price, or book a free survey.