When you’re planning a house extension in Bexley, getting several quotes is a sensible step. But the final figure only tells you part of the story.
One builder may have included decorating, flooring and external drainage. Another may have priced the shell and left the rest as allowances or exclusions. Until you understand those differences, you aren’t comparing the same job.
The useful question isn’t simply “Which quote is cheapest?” It’s “What does each price actually cover?”
Start with the same information
Give every builder the same drawings, specification and supporting information. If the design changes during the tender process, make sure everyone receives the revised details.
Planning drawings can explain the overall shape of an extension without resolving every construction detail. Structural information, drainage proposals, window specifications and finish schedules may still need developing.
Where something hasn’t been decided, ask each builder to identify their assumption. That gives you a clearer basis for comparison than several prices built around different interpretations.
Check where the work starts and finishes
An extension rarely stops neatly at the new walls.
Connecting the new space to the existing house can involve alterations to floors, ceilings, heating, electrics and decoration. Outside, the work may affect patios, paths and landscaping.
Ask whether the quote includes making good these areas. “Kitchen extension” is not a detailed scope on its own.
The same applies to demolition, waste removal, access arrangements and protection of the existing home. These should be addressed rather than left for discussion once work starts.
Understand allowances and exclusions
An allowance is not the same as a fully specified item with a firm price.
A kitchen allowance, for example, needs context. Does it cover units, worktops and appliances? Is installation included? What about plumbing connections, electrical work and decoration?
Where a quote uses provisional sums, ask what each sum covers, how it was estimated and how the final cost will be agreed.
Read exclusions just as carefully as inclusions. An excluded item does not disappear from the project. It may simply become something you need to arrange and pay for separately.
Coordinate glazing, structure and finishes
Large glazed openings, rooflights and open-plan layouts can make an extension work beautifully, but their details need to fit together.
Ask who is responsible for coordinating the structural openings, glazing dimensions, thresholds and finished floor levels. Establish who supplies and installs specialist items and who checks the information before orders are placed.
Our Melbourne Grove project in Dulwich combined a kitchen extension with the removal of a wall between the kitchen and living area, large windows, skylights and bespoke cabinetry. That combination illustrates why an extension needs to be considered as a complete space, not simply additional floor area.
Look beyond the proposed start date
A start date matters, but so does the sequence of work.
Ask what needs to be resolved before the programme can be agreed. Outstanding design decisions, approvals and specialist orders may affect when particular stages can happen.
If you plan to remain at home, discuss access, temporary kitchen arrangements, service interruptions and separation from the work area. Do not assume that staying in the property will be practical throughout every stage.
A useful programme should explain the key stages and dependencies, not just give a completion date.
Clarify approvals and responsibilities
Planning permission and building regulations approval are separate matters. Depending on the work, party wall requirements may also need consideration.
Agree who is arranging the relevant applications, design information and inspections, and whether associated fees are included in the quotation.
Your designer, building control professional and, where relevant, a party wall surveyor should confirm the requirements for your particular property. A builder’s quotation is not a substitute for that advice.
Agree how changes will be handled
Even a well-prepared project can change. The important thing is having a clear process.
Before appointing a builder, agree how variations will be described, priced and approved, including any effect on the programme. Ask for proposed changes to be recorded in writing rather than relying on conversations on site.
Also clarify the payment stages, handover information and arrangements for reporting and resolving defects.
Planning an extension in Bexley?
At Ryan and Sons Construction, we welcome enquiries about extensions and refurbishments across Bexley, North Kent and South East London.
Send us your project address, available drawings and a short outline of what you want to achieve. Let us know your intended timescale and any important requirements, such as remaining at home during the work.
Contact Sean at sean@ryanandsons.co.uk or visit our contact page.
