Quick answer
The construction period is only one part of an extension programme. Design, surveys, approvals, engineering, quotation, product lead times and final fit-out all happen around the build. A realistic plan starts before anyone arrives on site.
For property-specific advice, speak to the appropriate planning, design or building-control professional and request a clear written scope from your builder.
Stage 1: brief, survey and design
The first stage defines what the extension must achieve and tests the idea against the property, budget and constraints. Drawings may develop through several versions before the layout and external appearance are ready for approval and pricing.
Stage 2: planning and technical information
The planning route depends on the design and property. Building-regulations drawings and structural calculations may also be required. Read our guide to planning permission for house extensions.
These processes can overlap in some projects, but assumptions should not be treated as approvals.
Stage 3: quotations and pre-construction choices
Builders need consistent information to price the same work. Windows, doors, roofing and other long-lead items should be selected and ordered at the appropriate time. Access, start dates, payment stages and responsibilities need agreement.
Stage 4: construction and fit-out
- Site setup, excavation and foundations
- Drainage, floor, walls and structure
- Roofing, windows and weatherproofing
- Structural openings into the existing house
- First-fix services, insulation and plaster
- Kitchen, second-fix services, flooring and finishes
- Testing, inspections, snagging and handover
Weather, unforeseen ground conditions, design changes, inspection timing and product delays can affect the programme. A larger or highly specified extension naturally takes longer than a simple build.
Related services and guides
Frequently asked questions
Can an exact completion date be guaranteed?
A programme can be planned, but weather, hidden conditions, approvals, supply issues and client changes can affect completion.
Can design and planning be rushed?
Rushing early decisions can produce later changes. A resolved design generally supports better pricing and construction.
When should the kitchen be ordered?
It should be coordinated with verified dimensions, the build programme and supplier lead times.
What commonly causes delays?
Late choices, variations, long-lead products, inspection timing, weather and unforeseen site conditions are common causes.
Planning work on your Colchester home?
Essex Builders can discuss the practical building work, arrange a site visit and provide a clear written quote for suitable projects across Colchester and nearby Essex areas.
Request a free quoteCall 07958 355936