A typical design of a structure could have twin reception rooms, (rear and front), with the rear room joists usually running from the spine wall (the wall you may be opening) to the external walls.You will need to inform the local building inspector that you are intending to carry out work to the property who will be happy to advise on ensuring the alteration is to current standards.Any wall that is bearing the weight of joists is therefore load bearing and will have to be supported prior to any major alterations undertaken.

All you need to do now is make good the plaster work afterwards.Before taking any masonry away, mark out the opening in the wall that is required. Pack up the lintel with slate afterwards to ensure it is tight to the masonry above. After the structure is propped and secure you can start the opening by using an angle grinder at the openings boundary or by using hammer and bolster. Typically corrugated steel sheet this would be done with the use of acrow props and timbers needles or steel supports called strong boys to take the load whilst alterations are underway. A structural engineer will be able to help you choose the right support for the job.

Bed the lintel onto a stiff 3:1 mix of sand and cement sitting on concrete pad stones. Building regulations is required for most structural alterations so you must make enquiries before commencing works. Never guess and think you know if you are not entirely sure! Structural engineers are paid to calculate loads and will save you a hell of a lot of money if you get it wrong and calculate incorrectly. This way you will know exactly what you are taking away and also ensuring there are no hidden pipe or cables that may cause an obstruction.

Only after this can the props be taken away and in doing so, fill in any holes you made for the props with bricks and point up and slate if required. This structure will need to be supported by using a lintel which may be of either concrete or steel construction depending on the engineers specifications for the job.Leave your support props in until the next day to let the mortar set.This may be a brick load or even the floor timbers so it will be necessary to do a few checks first. Some scaffold boards spanning trestles offer a safe way to do this. Use a hammer and bolster to remove any plaster on the wall. In the same fashion the load must be supported both before and after any alteration is taken out