How is the lintel selected?
Selection depends on the wall construction, opening span, available bearings and loads above. Catnic's guidance distinguishes the lintels used for different wall types and loading conditions, rather than selecting a product by length alone. A cavity-wall opening also needs an arrangement appropriate to its separate wall leaves. [2]
Ask the designer to specify the product or engineered member, not simply “lintel over”. Where a supplier assists with selection, request the assumptions supplied to them and confirmation that the proposed construction matches those assumptions.
A lintel is not interchangeable with every beam
Some openings can use a suitably selected proprietary lintel; others need a separately designed beam or a more extensive structural arrangement. Planning Portal explains that enlarging an opening can change both the required support over it and the adequacy of the masonry receiving the load. [3]
Ask for a specific review when the opening is widened, a pier is reduced, or the load above is changing as part of another alteration. Do not reuse an old detail simply because it worked before the extension or additional floor was proposed.
What must be checked on site?
NHBC's superstructure guidance addresses lintel bearings, correct positioning and support workmanship. These details need to match the specification: the overall product length is not the same as the clear opening it can safely span. [4]
For your inspection checklist, ask who will confirm the actual opening and support dimensions, who will review unexpected masonry, and when the work must remain exposed for checking. Request a photograph showing the whole installation rather than only the manufacturer's label.
Building regulations and window certification
LABC explains that structural work involving lintels is not simply covered by an installer's window-replacement certification. A competent person scheme for windows should not be treated as approval of a separate structural alteration. Check the building-control route for the complete job. [5]
England's approval guidance includes structural alterations among work that may require building-regulations approval. Planning permission and building regulations address different matters, so the absence of a planning application does not resolve the structural requirements. [6]
Plan the temporary condition
Creating an opening in supporting masonry requires a safe sequence and suitable temporary support. HSE requires stability to be considered during alteration, not just after the new member is in place. This is not work to start from a lintel supplier's dimensions alone. [7]
Before ordering doors or windows, request a coordinated issued opening detail. Ask the team to resolve structure, finished dimensions and the surrounding construction together. Record any change before it reaches the fabricator or installer, and retain the final lintel specification with the building-control and completion records.