Steel Frame & Brick First-Floor Extension

The ground floor of this Kent family home needed to open right out into the garden, which meant taking away structural walls that were holding up everything above them. At the same time the clients wanted to gain a full extra storey, so whatever replaced those walls had to carry not just the existing loads but a new floor and roof on top.

That combination is what makes a job like this a structural exercise before it is a decorative one. Get the steel and the masonry right and the rest of the build is straightforward. Get it wrong and it shows up in cracked plaster two years later.

We installed a steel goalpost frame supported on new brick piers, so the rear elevation could be opened into wide glazed bays with no masonry crossing the openings. Padstones and bearings were set out to the engineer's details, and the frame was levelled and packed before anything was loaded onto it.

New timber floor joists were then laid off the steels and decked out, which gave us both the structural deck for the storey above and a safe working platform to build off. From there the new first floor went up as a traditional cavity wall: a blockwork inner leaf and a reclaimed-look red multi facing brick outer leaf, tied together with stainless wall ties at the correct centres.

The details that matter here are the ones you stop being able to see once the job is finished. Cavity trays and DPC were built in over every opening and at the base of the new work, weep vents were left open to let the cavity drain, and service ducts and vent terminals were built into the brickwork as the courses went up rather than cut in afterwards. The whole elevation was built under a full scaffold with a temporary roof, so the house was never left open to the weather.