How to choose a garage conversion builder
A useful comparison goes beyond a headline price and a finished-room photograph. Check the builder's relevant experience, how the garage will be assessed and what the written agreement covers.
Use these twelve checks when comparing JB with any other company. Ask for clarification where evidence is missing.
Start with your proposed room, storage needs and specification so that different quotations can be compared on the same basis.
In this guide
- 01.Check Relevant Experience
- 02.Ask For Project Evidence
- 03.Agree Approval Responsibilities
- 04.Understand The Survey
- 05.Compare The Specification
- 06.Read The Written Agreement
- 07.Check Current Insurance Information
- 08.Read Reviews And Speak To References
- 09.Identify Who Is Responsible On Site
- 10.Agree Payments And Completion
- 11.Read The Guarantee Terms
- 12.Resolve Differences Before Deciding
- 18 comparison questions
- 10 red flags
- Builder scorecard
- A note from James Benton
- 8 frequently asked questions
The 12 Checks
Work through all 12 before signing anything.
- 01
Check Relevant Experience
Ask for garage conversions comparable with your proposed room and existing structure. A specialist label alone does not establish competence; relevant work and clear answers are more useful.
- 02
Ask For Project Evidence
Request before, during and after photographs where available, plus references with the customers' permission. Missing photographs are not proof of poor work, but other evidence becomes more important.
- 03
Agree Approval Responsibilities
Converting a garage, including only part of it, into living accommodation normally requires building-regulations approval. This is separate from planning permission. Before work starts, agree the approval route, who makes the application, the inspection stages and who pays the fees. Any application support provided by JB is set out in the quotation; required approval is not an optional upgrade.
- 04
Understand The Survey
Ask which parts of the garage have been inspected and what remains uncertain. Discuss structure, damp, access, services and intended use before relying on a price.
- 05
Compare The Specification
Compare floors, insulation, openings, services and finishes. Check inclusions, exclusions, allowances and client-supplied items, not just the final sum.
- 06
Read The Written Agreement
Ensure the agreed parties, work, price basis, payment stages, programme and change process are clear. Ask how concerns or disputes will be handled.
- 07
Check Current Insurance Information
Request relevant insurance documents and check the insured business, dates and scope. Ask the provider or your own insurer if you need clarification; a certificate is not a guarantee that every situation is covered.
- 08
Read Reviews And Speak To References
Read recent reviews and ask previous customers about communication, changes, workmanship and aftercare. Consider a range of evidence rather than a star rating alone.
- 09
Identify Who Is Responsible On Site
Ask who will manage the project, who will do the work and how subcontracted trades are coordinated. Identify your main contact.
- 10
Agree Payments And Completion
Agree payment milestones and the process for inspecting finished work, recording snagging and closing outstanding items. Do not assume every contract uses a retention.
- 11
Read The Guarantee Terms
Ask who provides the guarantee, what work it covers, its duration and exclusions, and how a claim is made. Insurance backing is a separate claim that needs evidence.
- 12
Resolve Differences Before Deciding
Ask each builder to explain gaps between specifications. A lower or higher figure alone does not establish quality or suitability.
18 Questions To Ask Every Builder
Use these 18 questions when speaking to any builder. Note the answers and compare them across the companies you are considering.
- 01
What proportion of your work is garage conversions?
- 02
Can you show me before, during and after photographs of recent projects?
- 03
How do you handle building control — do you help prepare the application and coordinate inspections?
- 04
What does your site visit involve, and who carries it out?
- 05
What does your quotation include and exclude — specifically the floor, insulation, electrics, plastering and finishes?
- 06
Do you provide a written contract, and what does it cover?
- 07
Can I see your current public liability insurance certificate?
- 08
Can you provide references from recent customers with similar projects?
- 09
Who will be on site — your own employees or subcontractors?
- 10
How is the snagging process handled, and when is final payment due?
- 11
What workmanship guarantee do you offer, and what are the exclusions?
- 12
How do you handle variations — will you notify me before incurring additional costs?
- 13
What is the realistic programme for my project?
- 14
Who is my main point of contact during the build?
- 15
Have you worked on properties similar to mine in terms of construction type and age?
- 16
What happens if the project runs over programme?
- 17
How do you manage the site — waste removal, access, working hours?
- 18
What is your process if I am not satisfied with the finished work?
10 Red Flags
Pause and request clarification when important evidence or responsibilities are missing. Assess the response and the project as a whole.
For the practical problems these checks are designed to prevent, read our guide to garage conversion mistakes to avoid, covering surveys, damp protection, specification gaps and missing records.
A project price is offered without explaining what has been surveyed or assumed.
Relevant project evidence or references cannot be verified.
Required approvals are dismissed without checking the property and proposed work.
The scope, price basis or change process is not recorded in writing.
Relevant current insurance information cannot be provided.
Upfront payments are requested without clear milestones and terms.
Completion, snagging and payment responsibilities remain unclear.
Review or reference claims cannot be checked.
A price difference is not explained by the specification or exclusions.
You feel pressured to sign before your questions have been answered.
Builder Scorecard
Use this checklist to record what each builder has demonstrated and what still needs clarification. It is an aid to comparison, not a certification or a guarantee of the result.
| # | Check | Pass / Fail |
|---|---|---|
| 01 | Shows relevant garage-conversion experience | |
| 02 | Provides construction-stage project evidence | |
| 03 | Explains approvals and responsibilities | |
| 04 | Carries out a thorough site visit | |
| 05 | Provides a detailed written quotation | |
| 06 | Provides a written contract | |
| 07 | Holds current public liability insurance | |
| 08 | Has verifiable reviews and references | |
| 09 | Can explain who will be on site | |
| 10 | Has a clear snagging and completion process | |
| 11 | Offers a meaningful workmanship guarantee | |
| 12 | Quotation is detailed enough to compare |
Print this page or note scores in a spreadsheet when comparing multiple builders.
Apply These Checks To JB Too
Explore our project photographs and current Google reviews, then ask about work comparable with your own plans.
Request the proposed specification, approval responsibilities and written guarantee terms alongside your quotation.
Our ten-year workmanship guarantee is provided by the business and is not insurance-backed. Its written terms explain the scope and how to raise a concern.
If you would like to discuss your project, send us an enquiry. We will call to discuss the next steps, with no obligation.
JB Garage Conversions
Partial from £11,000 · Single from £14,000 · Double from £20,000+
Starting guides, subject to survey and specification. A written quotation confirms the agreed work, allowances and exclusions.
Frequently Asked Questions
Apply These Checks To JB Garage Conversions
We welcome every question on this list. Send us an enquiry and we will call to discuss your proposed room, any storage you want to retain and the next steps. Ask for the written scope, approval responsibilities and guarantee terms before making your decision.
Check the requirements for your property
General guidance is a starting point, not approval for a particular garage. Read the Planning Portal guidance on garage conversion planning permission and building regulations, then confirm the requirements with the relevant local planning authority and building control body.