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CNJ Construction Consultants

CNJ Construction Consultants

Know Your Build Costs Upfront

CNJ Construction Consultants support homeowners with construction cost planning, budget control and project advice before and throughout their build.
CNJ supports homeowners across Surrey, London, and the South East with construction cost advice, project planning, and professional support throughout residential building projects.
Our team supports clients with budgeting, feasibility reviews, project planning, tender support, and ongoing cost management throughout the construction process — helping reduce risk, avoid unexpected costs, and keep projects on track.
Cost Consultants for Homeowners

How CNJ Supports Homeowners

Before You Start Building

Construction cost planning and early-stage advice to help you understand likely project costs before work begins.

Support Throughout Your Build

Ongoing construction cost management and project support to help keep budgets and decisions under control.

Why Choose CNJ

Learn more about our experience supporting homeowners and residential construction projects.

Contact

Speak to a construction consultant about your plans, costs or concerns before committing to the next stage.

Associated With Professionals Across the Sector

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Cost Control for Homeowners
Who we are

Construction Cost Advice, Built Around You

Our team of 11 brings over 50 years of combined experience in quantity surveying, project management, and construction.

We provide clear, accurate construction cost advice, cost estimates and tender support that protect your budget, reduce risk, and keep your project on track — from the very first sketch through to completion.

What we offer

Our Services for Homeowners

Basic Cost Estimate

Get a quick, high-level overview of your project’s cost. Perfect for early feasibility and budget planning.

Detailed Cost Report

See exactly where your money would be going with a full cost breakdown, tailored to your project.

Tender Packages

We manage the tender process to vet contractors, handle queries and negotiate best and final quotations.

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Your Trusted Cost Partner

Why Homeowners Trust CNJ

A Team That Responds

With 10+ staff, we’re big enough to move quickly — unlike one-person consultancies.

6 Years in Business

A proven track record helping homeowners plan and manage their projects.

50+ Years’ Experience

Expertise across surveying, construction, and project management under one roof.

Accurate & Honest

Our values guide every report and recommendation we provide.

Our Proven 3-Step Approach Gives You Clarity on Costs and Peace of Mind Throughout Your Build

Building work doesn’t have to be stressful. With CNJ, you’ll know your costs upfront and understand exactly where your money is going. Our 3-step approach gives you clear estimates, helps you choose the right builder with confidence, and keeps your project on track from start to finish.
Step 1: Share Your Plans
Send us your drawings or project details, and we’ll review where you’re at, whether it’s early sketches or full architect plans.
CNJ Sketches Construction Consultants
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Step 2: Get Your Cost Report

We'll prepare a full cost report, showing every detail of your project broken down and costed

Step 3: Tender & Build With Confidence
We work with you to build detailed tenders, vet contractors, and control costs throughout the build - give you peace of mind and protecting your budget.
CNJ Builders Work
Ready to Discuss Your Project?

01483 339 733

Call us directly, or share your details online and we’ll quickly assess the best way to help with your project

Homeowner Construction Consultancy FAQs

Planning a residential building project can feel overwhelming, especially when it comes to budgets, project planning, and managing construction costs. Below are some of the most common questions homeowners ask before starting an extension, renovation, or residential development project.

Do I need a construction consultant before starting a house extension?

Not every project will require the same level of support, but speaking to a construction consultant before work begins can help you understand likely costs, identify potential risks and make better-informed decisions before committing to a contractor or build programme. Early advice can also help reduce unexpected costs later in the project.

A construction consultant can help by reviewing budgets, contractor quotations and project allowances, as well as identifying areas where costs may increase. They can also provide independent advice throughout the build so that changes, extras and unexpected issues are assessed before they have a major impact on the overall budget.

Ideally, as early as possible. Bringing in a cost consultant before the project starts gives you a clearer understanding of likely costs and helps you budget more realistically. They can also provide ongoing support during the build if you need help reviewing changes, contractor costs or financial decisions.

Yes. CNJ can help homeowners review contractor quotations, identify potential gaps or unclear allowances, and assess whether the figures appear realistic for the proposed work. This can give you greater confidence before accepting a quotation or agreeing to additional costs during the build.

If you would like us to review your project costs or discuss your plans, contact CNJ.

A quantity surveyor is typically focused on the financial and contractual side of a construction project, including estimating, valuations and cost control. A construction consultant may provide broader project advice, combining cost guidance with practical support, risk management and help throughout different stages of the build. CNJ’s service is designed to give homeowners access to this wider support.

The best starting point is to establish a realistic budget before work begins, understand what is included in contractor quotations and allow for contingency costs. It is also important to control design changes and agree any additional costs before work is carried out. Independent construction cost advice can help you make informed decisions and reduce the risk of unexpected overspend.

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