How Long Does a Garage Conversion Take in 2026? (UK)
A standard single garage conversion takes 3–6 weeks on site in 2026, with a further 4–8 weeks of design, Building Regulations preparation and contractor lead-in before the first day of work. Most of the on-site time goes on insulation, blockwork to fill the old garage door opening, damp-proofing, and second-fix finishing — not the demolition people expect to dominate. Here is the realistic week-by-week timeline, the five things that add delay, and how to keep your conversion on track.
Garage conversion timeline, week by week
| Stage | Typical duration |
|---|---|
| Design, drawings & Building Regs application | 4–8 weeks (before site) |
| Strip-out & floor preparation | 2–4 days |
| Blockwork to fill garage door opening | 2–3 days |
| Damp-proofing, insulation & floor build-up | 3–5 days |
| First fix (electrics, plumbing, studwork) | 3–5 days |
| Plastering & drying | 4–6 days |
| Second fix & decoration | 4–7 days |
| Building Control final inspection | 1 day |
How the timeline runs
1. Design and Building Regs come first
Most garage conversions are Permitted Development and need Building Regulations approval rather than planning permission. Allow 4–8 weeks to get drawings, a structural calculation if the opening is load-bearing, and a Building Notice or full-plans application lodged.
2. The opening and the floor are the real work
Filling the old garage door opening with insulated blockwork, raising and insulating the floor to current U-values, and tanking against damp account for the bulk of on-site time — not strip-out.
3. Drying time is unavoidable
Fresh plaster needs several days to dry before decoration, and a screeded floor longer still. Building this slack into the programme prevents trapped-moisture problems later.
4. Final sign-off closes the job
Building Control inspects at key stages and issues a completion certificate — essential when you later sell the house.
Five things that add delay
- Load-bearing openings needing steel beams and structural calcs.
- Drainage relocation if adding a WC or utility.
- Damp and poor existing foundations discovered on strip-out.
- Material lead times on windows, doors and bespoke joinery.
- Building Control scheduling around bank holidays and busy periods.
FAQs
Related guides
- How to hire a trusted garage fitter
- How long does a kitchen renovation take?
- Cost guides
- Planning permission guides
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