Managing your budget: making your investment work harder

Starting an extension, renovation or remodelling project is a significant investment. Before thinking about what you would like to build, it is worth understanding what you can realistically spend — and what you want that investment to achieve.

Construction costs vary considerably depending on the size and complexity of a project, the condition of the existing house and the quality of the materials and finishes. Establishing a realistic budget early gives you the opportunity to explore what is possible before becoming committed to a particular scheme.

What does your budget need to achieve?

It is easy to focus on the cost of an extension in terms of pounds per square metre or the final construction figure. But a more useful question is often:

What difference will this investment make to the way you live?

An extra bedroom might provide much-needed space for a growing family. Replanning the ground floor could transform a cramped kitchen into a space that works for everyday life. Better connections to the garden, more natural light or improved energy performance can make an existing home feel completely different without necessarily adding a huge amount of floor area.

The value of a project is therefore not simply about how much it costs to build.

It is about what you gain from it.

Explore the options

There is rarely only one solution to a brief.

A larger extension might provide everything on your wish list, but a smaller extension combined with remodelling the existing house could achieve many of the same improvements. Alternatively, investing more in one part of the project — such as better glazing, natural light or the connection between the house and garden — might have a greater impact than simply adding more space.

Exploring different options early allows you to understand these trade-offs.

It also means you can make decisions about where your money is best spent before too much time and money has been committed to one approach.

When the brief and budget don’t align

It is common for an initial brief and budget not to align perfectly. That does not necessarily mean the project cannot work.

It may mean that the brief needs to be prioritised. Some elements may be essential, while others are desirable but could be introduced later. The layout may need to change, the extent of the extension reconsidered, or the budget redirected towards the parts of the project that will make the biggest difference.

Making these decisions early is much easier than discovering during construction that the project has become unaffordable.

Does improving your home add value?

There can also be a financial consideration beyond how you live in the house.

Nationwide’s 2025 research found that 35% of homeowners who had renovated in the previous five years were looking to increase the value of their property, while 26% were looking to add more space.

Their analysis of house-price data also found that creating an additional bedroom can have a significant effect on value. An additional bedroom was associated with an increase of 13% for a typical two-bedroom terraced property, 14% for a semi-detached property and 17% for a detached property. A loft conversion or extension incorporating a large bedroom and bathroom could add as much as 24% to the value of a typical three-bedroom, one-bathroom house.

These are statistical estimates rather than guarantees. The value of any individual project will depend on the property, its location, the quality of the work and what buyers value locally.

But property value should not be the only measure of a successful project.

A home can become significantly better to live in without producing an equivalent increase in its market value. The right project is the one that makes sense for the house and for the people living in it.

Speculate to accumulate — but carefully

Sometimes spending more can make sense.

Investing in a better-quality extension, improving the layout or creating a much stronger connection between the house and garden can produce benefits that go beyond the additional square metres.

This is the idea behind speculating to accumulate: an additional investment in the right part of a project can sometimes produce a disproportionately better result.

But it needs to be considered carefully.

The most expensive option is not automatically the best option, and an increase in property value should never be assumed to cover the cost of the work.

The important thing is understanding the relationship between cost, quality, usability and long-term value before deciding where to invest.

Make informed decisions

A well-considered budget is not simply a limit on what you can build.

It is a tool for deciding where your investment will make the biggest difference.

By exploring different options early, testing them against your brief and understanding their likely financial implications, you can make informed decisions about what to prioritise — and avoid spending money on things that matter less to you.

For SOLV, good residential architecture is not about designing the biggest project possible.

It is about understanding how you want to live, what your existing home can offer and what you can realistically invest — then finding the right balance between the three.

The aim is simple: to make your home work better, and to make your investment work harder

A clear design process helps keep your budget in focus, from the first ideas through to detailed drawings and construction.