How a build actually unfolds once work starts on site

Setup and groundwork

The first stage on site is usually setting up welfare facilities, protecting access routes, and marking out the building line before excavation begins. Groundwork includes digging and pouring foundations, laying drainage, and building up to damp proof course level, all of which typically needs a building control inspection before it is covered over.

This stage can look slow from the outside, since much of the early work is below ground and less visually dramatic than the walls that follow, but getting foundations right is the stage least forgiving of shortcuts.

Structure and roof

Once foundations are signed off, walls go up, whether blockwork, timber frame, or a mix depending on the design, along with any structural steel needed to form openings. The roof structure follows, and getting the building weathertight, meaning the roof covering and any external doors and windows are in place, is a key milestone because it protects the internal work that follows from the weather.

This is often the stage where the project visibly changes shape fastest, as the new space takes on its final form and scaffolding comes down from areas no longer needed.

First fix and services

First fix covers the trades that go in before walls are plastered: electrical cabling, plumbing pipework, and stud partitions where relevant. This stage often involves the most disruption inside an occupied house, since it can mean access through existing rooms to route new services.

Insulation goes in around this stage too, followed by plasterboard and plastering, after which the site quietens down considerably while everything dries out properly before decoration can begin.

Second fix and finishing

Second fix covers fitting kitchens, bathrooms, skirting, doors, sockets and switches, along with final connections for plumbing and electrics. Flooring, decoration and final snagging follow, and this stage is where the space starts to feel like a finished room rather than a building site.

Towards the end, a final clean and a walk-through with the client to check details closes out the build before handover, which is covered in more depth in our snagging and handover guide.

Common questions