“How long will it take?” is the question every homeowner asks before starting an extension — and it deserves an honest, specific answer rather than a vague estimate.
A Typical Single-Storey Rear Extension
Weeks 1–2: Groundworks & Foundations
Excavation, foundation pours, and drainage work. This stage is weather-dependent and can shift by a few days either way.
Weeks 3–5: Structural Build
Blockwork, steel beams, and the new roof structure go up. This is when the extension starts to take visible shape.
Weeks 6–8: First Fix
Plumbing, electrics, and plastering are carried out before anything is closed up, so every pipe and cable is exactly where it needs to be.
Weeks 9–11: Second Fix & Finishing
Flooring, kitchen or bathroom fitting, painting, and final electrical fittings are completed.
Week 12: Snagging & Handover
A full walkthrough with you to identify and resolve any final snags before handover.
What Can Change the Timeline
Planning permission delays, structural surprises in older properties, and material lead times are the most common causes of delay. A good builder builds realistic contingency into the schedule rather than promising an unrealistic date and missing it.
