An RSJ is the steel beam that carries the load once a wall is taken out. Our part is the survey, the propping, the beam, the padstones, the making good and the inspections that sign it all off. We appoint a structural engineer for the calculations and build to what they issue. We never produce those calculations ourselves. This page sets out what an RSJ job on a Windsor property involves, and who checks it.
Windsor building control books your steel in for its own inspection before it is encased
The Royal Borough of Windsor and Maidenhead lists a specific inspection stage for steel beams and columns before they are encased, with one day's notice required to book it. That is the point at which the beam, its bearings and its padstones can still be seen. Once the steel is boxed in and plastered, that opportunity has gone. We hold the programme so the inspection happens while the work is still open.
The council's other notice periods sit around it. It asks for two days' notice before work commences, one day's notice for foundation excavations and for steel beams before encasing, and seven days' notice before occupation. We make the building control application and book each of those dates against our own programme, so the trades that follow are not waiting on a visit nobody arranged.
What the Royal Borough charges to sign off a single beam
The council's building control charge category C3 covers structural alterations of a single beam or chimney breast removal. From 1 April 2026 that is £300.00 on a full plans application or £345.00 on a building notice, both inclusive of VAT. Those are the council's figures, not ours, and they sit alongside the build cost rather than inside it. We tell you which route we intend to use before you accept a quotation.
Three storey houses with cellars change where the beam has to land
A steel beam concentrates the load above it onto two small bearing points, and those points have to carry all the way down. The council's Inner Windsor appraisal describes dwellings along the area's major streets, such as Clarence Road, Frances Road and Kings Road, as three storeys high with cellars. Where a cellar sits beneath a bearing, the load path continues below the ground floor. We open up at the bearing position, record what is there and pass it to the engineer before the steel is ordered.
Getting a steel into a narrow fronted terrace needs a route, not just a lorry
A beam arrives on a lorry and is carried in by hand, so access is priced rather than assumed. The council's Inner Windsor appraisal describes the minor side streets as two storey terraces with narrow frontages. It records that access to the rear is either through the dwelling, by rear alleyway, or through passageways between individual properties.
At Gardner Cottages the pattern is set out in the building itself. Each terrace of twelve cottages has a larger cottage at each end and a pair of larger cottages in the middle, flanking a passage that leads to the rear. Whether the beam comes through the front door or round the back changes the length that can be handled and the propping sequence. We measure both routes at survey and agree the delivery point with you.
- Goalpost frames where two walls meet at a corner
- Beam boxing, fire protection and plasterboard encasement
- Structural openings for open-plan living
- Steel delivered cut, drilled and primed to the engineer's schedule
- Making good, plastering and finishing around the new steel
The GS Renovation Difference in Windsor
We are a contractor, not an engineering practice. For a Windsor beam we appoint the structural engineer, build to the calculations issued, and hold the propping until the steel is in and bearing correctly. The building control application goes to the Royal Borough of Windsor and Maidenhead, and we make it and book the pre-encasement inspection around our own programme rather than after the fact. That gives you one point of contact for the engineer, the steel, the brickwork and the sign off. GS Renovation Ltd is fully insured, registered in England, company number 14611254, and quotations are free and carry no obligation.
- Straight advice on what is and is not worth spending money on
- High-density concrete padstones bedded at every bearing
- Clean, tidy and reliable tradespeople
- Fully insured, with cover in place on every site
- Party Wall Act notices served where a beam bears into a shared wall
- Steel ordered cut, drilled and primed to the schedule