Frequently asked questions
Everything we get asked most — answered straight. If your question is not here, drop us a line and we will reply within one working day.
- Categories 4 groups
- Questions 20+
- Reply time 1 working day
- Free quote 2 min online
Planning & permissions
Do I need planning permission for an extension?
Many extensions fall under permitted development — meaning you do not need full planning permission. We assess your property on the first visit and confirm which route applies.
How long does planning permission take?
A standard householder application takes 8 weeks from validation. Conservation areas, listed buildings, or applications with objections may take longer. We track your application week by week.
What is a party wall agreement?
A legal agreement with neighbours whose properties share a wall with yours. Required before structural work near a shared wall begins. We arrange surveyors for both sides.
Can you handle conservation areas?
Yes — many of our SW London projects are within conservation areas. We have a long track record with the relevant councils and know the materials and detailing they expect.
Cost & timeline
How much does an extension cost?
In London, expect £2,500–£4,000 per square metre for a finished extension including kitchen and finishes. Use our calculator for a personalised estimate.
How long does a project take?
From first call to handover: typically 1–6 months for a standard extension or loft, 2–6 months for double-storey or wrap-around projects, and 12–24 months for new builds.
Are your prices fixed or do they change during the build?
We work to a fixed-price contract once design is finalised. Variations only happen if you change scope mid-build — and we always agree the cost in writing before proceeding.
Do you ask for a deposit upfront?
We don't ask for big upfront deposits. You pay in stages as work is completed and approved, so your money tracks our progress.
Working with Dali Pro Services
Can I live in the house during the build?
For most rear extensions and loft conversions, yes. We dust-seal the work area and maintain access to your kitchen and bathroom. For full new builds or wraparounds, we discuss alternative arrangements.
Do you handle architecture too?
Yes — we have in-house design partners. You can also bring your own architect if you prefer.
What happens if there is an issue after the build?
You get a 12-month workmanship warranty plus a 10-year structural warranty (NHBC, Premier or LABC). We respond to snagging issues within 5 working days.
Who will be my point of contact?
One dedicated project manager from the first sketch to the final snagging walk-through. Same number, same person, every week.
Still have a question?
Drop us a line — we reply within one working day, or call 0800 0432 333 between Mon–Fri 8am–6pm