James Desborough
You will almost certainly need a new lintel, as the new patio doors are larger. I would recomend a catnic lintel for a standard cavity wall. The job would consist of:- Cutting existing internal and external walls to a new opening 7ft Acro props should be placed correctly to support the wall above whilst these works are undertaken. A new catnic lintel installed, the lintel should have 6inch bearing each side, so in this intance the an 8ft lintel is required. Intallation of new door jambs and frame aswell as installation of larger sill, this also maybe at DPC level, so may require new DPC. Door fitted by window/door crontactor (FENSA approved) Making good plasterboard and plaster internal reveals, make good external wall (brickwork/render) A competent builder 3 days max, 2 man team.