Glazed Rear Extension in Highfields Caldecote

Project Scope and Construction

This single-storey rear extension in Highfields Caldecote has been handed over and is in use. Facing brickwork, anthracite aluminium corner glazing and a roof lantern give the family a bright new living room that opens straight onto the garden.

The photographs follow the build from foundations and brickwork through the steel, the warm roof, the glazing, plastering, electrics and decoration to the finished garden elevation.

Foundations and insulated ground floor

We prepared the site, dug and poured the concrete foundations, built the foundation masonry and laid a reinforced concrete floor slab with rigid insulation, perimeter upstand insulation and a screed finish.

You never see this stage again, but it is what makes a rear extension last. The foundations and floor have to suit the drawings and the ground, and the insulation and damp-proofing have to run unbroken into the existing house.

Cavity brickwork and structural support

The walls are facing brickwork with an insulated aircrete block inner leaf: 90 mm rigid cavity insulation, wall starters, cavity trays and lintels, with feature squint brickwork where the wall meets the glazed corner.

Structural steel, a channel and a square hollow-section column, carries the wide opening around the aluminium glazing. That is what lets the rear and side glass meet at the corner with nothing in the way while holding up the roof above.

This stage is a good example of how brickwork and blockwork must be coordinated with structural details and exact window and door dimensions rather than treated as an isolated trade.

Warm flat roof and roof lantern

The roof is a warm flat roof: joists and trimmers, plywood decking, rigid insulation above the deck and an EPDM single-ply covering, with a purpose-made upstand so the roof lantern sits within the insulated build-up rather than on top of it.

Inside, the lantern drops daylight into the middle of the room. In the finished photographs the lantern, the recessed lighting and the full-height glazing work together to make a compact extension feel open.

Aluminium glazing and internal finish

Anthracite aluminium windows and a large three-track sliding door make up the glazing. The finished exterior photographs show the slim dark frames against the new brickwork, with wide views and direct access to the garden.

Our internal work covered plasterboard, skim plaster, electrical points, recessed lighting and decoration; the finished photographs show the plastered and decorated room and the lantern. They were taken before the final floor covering went down, so we do not claim that later finish as ours.

Planning a similar extension

A glazed extension of this type depends on coordinated architectural and structural information. The steel support, corner glazing, roof lantern, warm-roof junctions and drainage details all need to be resolved before the relevant stages begin on site. Our permitted development guide and Cambridge extension cost guide cover the approval routes and realistic budgets for single-storey rear extensions.

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