10 Smart Ways to Save Money When Building a Home Extension
12 Jun 25 | News | 4 Min read
With UK house prices continuing to rise and homeowners seeking practical ways to create more space, building an extension has become a popular alternative to moving. From expanding kitchens to adding home offices or utility rooms, extensions offer flexibility and potential long-term value. However, the costs involved can be significant—and they can quickly spiral without proper management.
According to industry averages, a single-storey extension typically costs between £1,500 and £2,500 per square metre. So how can you make the most of your investment while keeping your budget in check? Here are ten practical and effective ways to save money during your extension project, without cutting corners on quality or comfort.
1. Plan Thoroughly Before You Start
Comprehensive planning is essential to avoid delays, changes, and unexpected expenses later. Investing in detailed architectural drawings at the beginning ensures that all contractors are working from the same blueprint.
A well-thought-out plan will also make it easier to gain planning permission and building regulations approval, avoiding potentially costly setbacks down the line. Hiring a reputable architect or architectural technologist who understands your vision is a smart first step.
2. Set a Realistic Budget—And Monitor It
Be honest about what you can afford, and ensure your budget includes all elements of the build—from design fees and permissions to labour, materials, fixtures and fittings. Crucially, set aside a contingency fund of around 10 to 15 per cent to cover any unforeseen issues.
Keeping a detailed spreadsheet of your expenses and updating it regularly will help you stay in control and avoid nasty surprises.
3. Stick to a Simple Design
It might be tempting to create something architecturally unique, but the more complex your extension, the more expensive it will likely be to build. Unusual shapes, bespoke glazing, or curved walls require specialist labour and custom materials.
By choosing a clean, rectangular layout with a flat or pitched roof, you can significantly cut both material and labour costs while still achieving an attractive and functional space.
4. Take On Some DIY (If You’re Confident)
If you’re competent and have the time, handling some of the finishing work yourself can lead to substantial savings. Painting, decorating, basic tiling, or even simple landscaping are all tasks many homeowners can do to a good standard.
However, don’t be tempted to tackle specialist work such as electrics, plumbing, or anything structural unless you’re properly qualified. Doing so could void your insurance, compromise safety, or lead to expensive corrections.
5. Choose Cost-Effective Materials
Expensive doesn’t always mean better. There are countless durable and visually appealing alternatives to high-end materials. Engineered wood, for instance, offers the look of hardwood flooring at a fraction of the cost, while composite cladding or uPVC windows can mimic more expensive finishes.
Reclaimed materials, salvage yards, and architectural reuse centres can also provide unique character at lower prices.
6. Compare Multiple Quotes
Prices between contractors can vary considerably. Rather than accepting the first quote you receive, aim to get at least three detailed quotations. Make sure they’re itemised, so you can compare like for like.
Beyond just cost, assess each contractor’s reputation, communication skills, and previous work. Cheapest isn’t always best—look for the best value overall.
7. Time the Project Wisely
Most homeowners aim to build in spring or summer, but this is often the busiest (and most expensive) time for tradespeople. You may be able to negotiate better prices or faster start dates during quieter seasons, particularly in late autumn or early winter.
This is especially useful if much of the work can be done indoors, or if the site can be properly weatherproofed during construction.
8. Consider a Design-and-Build Company
Using a single firm to handle both the design and construction aspects of the project can streamline the entire process and reduce costs. It minimises miscommunication between architects and builders and helps keep the timeline on track.
Many design-and-build firms offer fixed-price contracts, which can also provide greater budget certainty.
9. Reuse What You Already Have
Before knocking everything down and starting afresh, look at what can be retained or adapted. Keeping existing walls, doorways, or footings can dramatically reduce labour and material costs.
Similarly, maintaining the location of plumbing and electrical installations—such as keeping kitchens or bathrooms in their original position—can avoid the need for major rerouting and additional expense.
10. Don’t Overspecify Where You Don’t Need To
It’s easy to get carried away choosing premium finishes or high-end features. While these can add a touch of luxury, they don’t always offer great value—particularly for elements that aren’t visible or frequently used.
Focus on areas that contribute to long-term comfort and efficiency, such as good insulation, energy-efficient windows, and reliable roofing. Opt for mid-range fixtures and fittings for now, and upgrade them over time if desired.
A home extension can transform your living space and increase your property’s value—but it’s crucial to approach it with careful planning and cost awareness. With clear priorities, smart choices, and a disciplined approach, you can stay on budget without compromising your goals.
In today’s uncertain housing market, saving money doesn’t have to mean cutting corners. It simply means working smarter—and building better.
