Progress photographs showing the early construction stages of a rear extension. The images document a freshly poured concrete floor slab within the perimeter brickwork, followed by brick walls and a lintel spanning the opening.
About this type of work
The notes below explain this kind of work in general terms. Every home is different, so the details of a particular job depend on the property, the ground and what the owner wants.
The early stages of a rear extension
The photographs show the first stages above ground. They follow the foundations, which are dug and filled with concrete before any walls are built.
- Foundations. Trenches are dug to a depth set by the ground, then filled with concrete. Building control normally inspects them before they are covered.
- Walls up to ground level. Brick or block walls are built up to the damp-proof course, which stops moisture rising into the structure.
- The floor slab. Compacted hardcore, insulation and a damp-proof membrane are laid, then concrete is poured over them. One photograph shows a fresh slab inside the brickwork.
- The walls. Cavity walls rise to the right height, with insulation in the cavity and wall ties holding the two leaves together.
- Lintels. Where there is an opening, such as for a door or window, a lintel is built in above it to carry the wall above. Another photograph shows one spanning the opening.
The roof, windows and doors, services and finishes come after this. Our guide to the build stages explains the full order of work.
What to check
- Planning. Many single-storey rear extensions on houses are permitted development, within limits on depth and height, but flats and homes in conservation areas have different rules.
- Building Regulations. They apply to almost every extension, and inspections happen at set stages as the work goes on.
- Party walls. Building close to a boundary or cutting into a shared wall may need a notice under the Party Wall etc. Act 1996.
Read our guides to the stages of an extension build and rear extensions, or ask us about yours.