Extending your home is one of the most impactful ways to gain space, improve flow, and add value — but success starts with a clear plan. Here’s a straightforward, step‑by‑step guide that keeps the process organised, compliant, and stress‑light from first idea to final handover.
Step 1: Define aims and budget. Begin by setting tangible goals: more family space, a larger kitchen, a home office, or better indoor–outdoor connection. Establish a realistic budget with a contingency (typically 10–15%) to cover unknowns uncovered during construction. Prioritise must‑haves versus nice‑to‑haves so design decisions stay focused.
Step 2: Assess feasibility. Commission a measured survey of the existing property, note services and drainage, and review orientation, overshadowing, and access. An architect can quickly flag constraints, from roof heights to overlooking and heritage considerations, and outline what’s achievable within your budget.
Step 3: Concept design. Explore options through sketches and 3D studies that test layout, light, and flow. Consider how the extension interacts with the garden, where storage will live, and how circulation improves. Early choices on glazing, insulation, and materials set the tone for aesthetics and energy performance.
Step 4: Planning strategy. Confirm whether the scheme fits Permitted Development or needs full planning permission. If risks exist (mass, appearance, or neighbour impact), a pre‑application discussion with the council can de‑risk the submission. Good neighbour engagement also helps reduce objections.
Step 5: Developed design and approvals. Progress to detailed drawings, specifications, and structural calculations. Prepare information for Building Regulations approval and, if applicable, Party Wall Act notices. At this stage, refine details such as roof build‑ups, window systems, and thermal performance to balance comfort and cost.
Step 6: Tender and contractor selection. Issue a clear tender pack to two or three vetted builders. Compare like‑for‑like pricing, programme, and preliminaries rather than headline cost alone. Put a simple written contract in place, define payment stages, insurances, and change‑control procedures before any work starts.
Step 7: Site preparation and mobilisation. Agree a start date, site access, welfare, and protection for existing finishes. Your architect or contract administrator should chair kick‑off meetings, confirm responsibilities, and set communication rhythms so decisions are made quickly on site.
Step 8: Construction and quality control. Expect phased inspections for structure, insulation, and services. Track variations transparently, record decisions, and keep the design intent front and centre. Small tweaks are normal; unmanaged scope creep is not. Aim for airtightness and careful detailing to avoid thermal bridges.
Step 9: Snagging and handover. As works conclude, compile a snag list, secure certificates (Building Control, electrical, gas), warranties, and manuals. Only release final payments once defects are addressed and documentation received.Step 10: Aftercare. Monitor seasonal performance, adjust ventilation and heating schedules, and plan maintenance for joinery and sealants. A well‑designed extension should feel effortless — brighter, warmer, and better connected to everyday life.