Construction of a two storey extension adding ground and first floor accommodation. Covers full structural build including foundations, walls, floors, roof, and weathertight shell.
Typical cost
£40,000 — £68,000
Typical duration
8-12 weeks
Certificate
Building Regulations approval required
Scope type
flexible
Typical tasks
Excavate and form foundations
Build external walls ground and first floor
Install intermediate floor structure
Construct roof and make weathertight
Install windows, doors, and internal stud partitions
Extras & additional works
Based on a standard double storey extension of approximately 40m². Costs may increase if access is restricted or high-end materials are chosen.
Common questions Stainesai
Factors include the size of the extension, choice of materials, site access, and location within the UK.
Planning permission is typically required for double storey extensions, but you may be able to use the prior approval route for larger extensions. Always confirm with your general builder before work begins.
Yes, Building Regulations apply to ensure structural integrity, energy efficiency, and safety standards are met.
A double storey extension usually takes 8-12 weeks to complete, depending on complexity and weather conditions. However, it's important to note that such extensions require Building Regulations approval and may also need planning permission. Always confirm with your general builder before work begins.
A double storey extension project includes excavation, building external walls, installing floors and roof, and fitting windows and doors. Building Regulations approval is required for all extensions and any structural work involved. Always confirm with your general builder before work begins.
Ready to post a double storey extension job?
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