Building Costs Guide for South East London
Understanding building costs helps you plan your project effectively. This guide provides typical price ranges for common building projects in Dulwich, Greenwich, Blackheath and surrounding areas.
Note: Every project is unique. These figures are indicative ranges — we provide detailed, itemised quotes for your specific requirements.
Loft Conversion Costs
Velux / Roof Light Conversion: £30,000 – £45,000
Ideal for lofts with good existing head height. Includes structural work, insulation, stairs, electrics, plastering, and decoration. No external changes to roofline.
Rear Dormer Conversion: £45,000 – £75,000
The most popular choice. Includes dormer construction, structural steel, stairs, full fit-out. Creates maximum usable floor area.
Hip-to-Gable Conversion: £60,000 – £85,000
For semi-detached/detached homes with hipped roofs. Includes structural alterations, dormer if required, full fit-out.
L-Shaped Dormer Conversion: £65,000 – £90,000
For properties with rear additions. Maximises space with L-shaped dormer following existing roof lines.
Mansard Conversion: £70,000 – £120,000+
Most extensive option, essentially creating a new floor. Usually requires planning permission.
House Extension Costs
Single-Storey Rear Extension: £1,800 – £2,500 per sqm (building work)
Example: 4m x 5m (20sqm) = £36,000 – £50,000
Includes foundations, walls, roof, bi-fold/sliding doors, electrics, plastering. Excludes kitchen fit-out.
Side Return Extension: £2,000 – £2,800 per sqm
Converting narrow side passage into additional width. Often combined with rear extension.
Two-Storey Extension: £2,200 – £3,000 per sqm
Double the space for approximately 50% more cost than single storey. Excellent value per sqm.
Wraparound Extension: £2,000 – £2,800 per sqm
Combines rear and side extension. Requires good site access.
Kitchen Costs
- Budget kitchen installation: £8,000 – £15,000
- Mid-range kitchen: £15,000 – £25,000
- Premium kitchen: £25,000 – £40,000+
(Kitchen unit costs additional to building work for extensions)
Bathroom Costs
- Basic bathroom refurbishment: £5,000 – £8,000
- Mid-range bathroom: £8,000 – £15,000
- High-end bathroom: £15,000 – £25,000+
- En-suite installation: £6,000 – £12,000
- Wet room: £8,000 – £15,000
What Affects Price?
- Project size and complexity
- Structural requirements
- Specification and materials
- Site access and conditions
- Planning and conservation requirements
- Your location within South East London
What's Typically Included
- All structural and building work
- Electrical installation
- Plumbing (where applicable)
- Plastering and decoration
- Building regulations compliance
- Project management
What's Usually Extra
- Planning application fees
- Kitchen/bathroom units and appliances
- Flooring
- Specialist finishes
Get Your Free Quote Today
Ready to start your project? Contact JT Allen for a free, no-obligation consultation.
- 07734 975051
- sales@jtallen.co.uk
- 12 Waterford, Battlesbridge, Essex, SS2 7GT