If you’re asking, “How can I reduce the cost of home extensions?”—you’re not alone. As material and labour prices rise, more homeowners across London and Surrey are looking for ways to make their budgets go further. At KT5 Construction, trusted extension builders across Surrey and London, we specialise in delivering bespoke extensions that are as structurally sound as they are stunning.

Smarter Planning Means Bigger Savings

Set a Clear Budget and Stick to It

Start by outlining your complete budget—don’t just think about build costs. Factor in:

• • VAT

  • Architect and engineer fees

  • Contingency fund (at least 10%).

Design Efficiently to Save More

Keep the Design Simple

Avoid unnecessarily large or complex layouts that require expensive steels or supports. Compact, efficient designs cost less and often function better.

Consider a Two-Storey Layout

Two-storey extensions often cost less per square metre than single-storey ones because you’re only adding one set of foundations and roofing.

Reduce Structural Changes

Use existing doorways or windows to access the new space. Avoiding internal knock-throughs reduces steelwork and labour.

Material Choices That Balance Style and Budget

Use Affordable Alternatives

Love the look of polished concrete or Crittall windows? Try concrete-look tiles or aluminium-framed glazing for the same aesthetic at a fraction of the price.

Mix High and Low-End Finishes

Splurge on elements that add long-term value (e.g. bifold doors, brick walls) and save on kitchens or flooring using cost-effective brands like IKEA or Howdens.

Choose Skylights Over Full Glass Roofs

Skylights deliver ample daylight without the high costs of structural glass and supporting steelsHow to reduce the cost.

Foundation & Structure Considerations

Design Around Site Conditions

Avoid building near trees, drains, or underground services to prevent the need for expensive specialist foundations.

Choose the Right Build System

Brick and block construction remains the most cost-efficient for extensions. Avoid costly modern systems unless your project scale justifies it.

Save on Admin and Planning

DIY Party Wall Agreements

Where neighbourly relations are good, use template Party Wall Notices instead of paying for a surveyor.

Avoid Building in Peak Seasons

Labour and materials are often more expensive around Christmas and early spring. Schedule your project to avoid seasonal premiums.

Why KT5 Construction Is the Smart Choice

With 25+ years of experience and hundreds of successful projects across London and Surrey, KT5 Construction is the trusted name for value-driven, high-quality home extensions.

Homeowners choose KT5 because we offer:

• • Free home surveys and budget consultations

  • Clear, honest pricing with no hidden fees

  • Expert advice to avoid costly design mistakes

  • Premium finishes tailored to your budget

  • Start-to-finish project support

Project Management Tips to Cut Costs

Manage Some Tasks Yourself

If you’re organised, acting as your project manager can save 10–15%—just ensure all trades know their responsibilities.

Reuse and Reclaim Materials

Sell or reuse bricks, tiles, and even fittings. This reduces waste and saves on skip hire and new materials.

Avoid Unseen Expenses

Plan for Waste Disposal

Skips and landfill charges add up. Plan waste logistics early and consider local recycling where possible.

Communicate Clearly with Your Team

Frequent updates between you, your builder, and your designer prevent costly missteps and delays.

FAQ: How Can I Reduce the Cost of Home Extensions?

Q1: What is the cheapest type of extension to build?

A single-storey rear extension with a simple layout and pitched roof is typically the most affordable. Avoid complex shapes, large spans requiring steelwork, or bespoke glazing.

Q2: Can I save money by managing the project myself?

Yes, taking on the role of project manager can reduce costs by up to 15%, especially if you can source trades and materials yourself. However, it requires excellent coordination and time management.

Q3: Do I need an architect for a small extension?

Not legally, but hiring one can improve planning success, optimise space use, and help avoid costly design errors. KT5 Construction works with architects or can recommend trusted partners.

Q4: How do skylights compare to a glass roof in cost?

Skylights are significantly cheaper than structural glass roofs. They offer similar natural light without the need for extra steel or specialist installation.

Q5: Is it more expensive to build in winter?

Yes. December often brings material cost spikes and availability issues. Planning your extension during off-peak months can help reduce costs.

Call to Action

Want to know how to reduce the cost of your home extension—without cutting corners? Book a free consultation with KT5 Construction today. Let us help you build smarter, not pricier.