What Is a Feasibility Study in Construction? A Plain-English Guide

Before a single brick is laid, one question decides whether a building project is worth pursuing: does it actually stack up? That is exactly what a feasibility study is for. Whether you are thinking about an extension, a block of flats or a new commercial unit, a feasibility study tells you early on whether the idea is practical, affordable and likely to pay off.

At Peters Cost Consultants we work with homeowners, developers and businesses across Hampshire and the rest of the UK, and a good feasibility study is one of the most valuable things we can produce for them. In this guide we explain what a feasibility study in construction involves, what it covers, when you need one and how to get the most from it, in plain English and without the jargon.

What Is a Feasibility Study in Construction?

A feasibility study is an early assessment of a proposed project. It looks at the idea from every important angle, including the cost, the site, the planning position, the timescale and the risks, and then gives you a clear answer on whether to go ahead, change the plan or walk away.

Think of it as testing the idea on paper before you spend real money on it. A good study does not just say yes or no. It shows you what the project is likely to cost, what could go wrong, and what options you have to make it work better. That makes it much easier to decide with confidence, and to explain your decision to a lender, a partner or a board.

It is worth saying what a feasibility study is not. It is not a full design, and it is not a fixed price quotation. It sits at the very start of the process, before detailed drawings and tenders, which is why it is so useful. Changing your mind at this stage costs very little. Changing it halfway through construction can cost a fortune.

Why a Feasibility Study Matters

Many projects that run into trouble were never properly tested at the start. The budget was a guess, the site had a hidden problem, or the planning route was harder than expected. A feasibility study is designed to surface those issues while you can still do something about them.

The main benefits are:

• Money saved. Spotting a poor idea early means you do not pour funds into design and surveys for a project that will never work.
• Clearer budgets. You get a realistic cost range rather than a hopeful figure, which makes funding conversations far easier.
• Fewer surprises. Site constraints, access issues and planning risks are identified before they become expensive problems.
• Better decisions. You can compare options side by side and choose the one that suits your goals and your budget.
• Stronger funding applications. Lenders and investors like to see that a project has been properly tested.

What Does a Feasibility Study Cover?

The exact content depends on the project, but most studies look at the same core areas. Here is what to expect.

The brief and the objectives

Every study starts by defining what you want to achieve. Are you building to sell, to rent, to live in or to run a business from? The answer shapes everything else, from the size of the building to the level of finish and the return you need.

The site

The site itself is often the biggest factor. The study looks at the size and shape of the plot, access, ground conditions, nearby buildings, services such as water and electricity, flood risk and anything else that could limit what you can build or add to the cost.

Planning and regulations

There is little point designing something that will not get permission. The study considers the local planning policy, any conservation or listed building restrictions, and the building regulations the project will need to meet. This gives you an honest view of how difficult the planning route is likely to be.

Costs and budget

This is where a cost consultant earns their fee. We prepare an outline cost estimate using measured quantities and up-to-date rates, and allow for fees, contingencies and other costs that are easy to overlook. If you would like to see how early budgets are built, our guide to construction cost planning vs budgeting explains the difference.

Programme and timescale

A realistic timetable matters, particularly if you are borrowing money or have a deadline. The study sets out the likely stages, from design and approvals through to construction and handover, so you know how long the project could take.

Risks and options

Every project carries risk. A feasibility study identifies the main ones and suggests ways to manage them. It will also often compare options, for example a smaller scheme against a larger one, or different layouts, so you can see which gives the best result.

Who Needs a Feasibility Study?

Almost anyone considering a significant building project can benefit. The people we most often work with include:

• Homeowners planning a large extension, a loft conversion or a new build.
• Developers deciding whether a plot or a building is worth buying.
• Landlords and investors looking at conversions or refurbishments.
• Businesses planning new premises, warehouses or an expansion.
• Schools, charities and public bodies preparing a case for funding.

If you are about to commit a large sum of money to a project, a feasibility study is one of the best investments you can make before you do.

When Should You Carry Out a Feasibility Study?

As early as possible. The ideal time is once you have an idea and a site, but before you have bought the land, paid for detailed drawings or signed any contracts. At that stage you still have every option open.

It is also worth doing a study if a project has stalled or the budget has crept up. A fresh look can show whether the scheme can be rescued, trimmed or redesigned. Sometimes the answer is to use value engineering to bring costs down without hurting quality, and our article on value engineering explains how that works.

How a Feasibility Study Works, Step by Step

Although every project is different, the process usually follows a similar path.

1. Initial conversation

We talk through your ideas, your budget and your timescale. This helps us understand what a good result looks like for you.

2. Information gathering

We collect what is already known about the site and the project, such as plans, surveys, planning history and any existing reports. If more information is needed, we advise on what to commission.

3. Analysis

We assess the site, the planning position, the likely costs and the programme. Where it helps, we look at more than one option so you can compare them.

4. Cost appraisal

We produce an outline cost estimate and, where relevant, a simple appraisal showing the likely value or return. For larger schemes this can include cash flow, so you can see when money goes out and when it comes in. Our piece on project cost planning gives more background on how this is done.

5. The report

You receive a clear written report with our findings, the main risks and our recommendation. We talk it through with you so that you understand every part of it and can ask questions.

What Does a Feasibility Study Cost?

The cost depends on the size and complexity of the project. A straightforward study for a domestic extension is relatively modest, while a study for a large commercial or residential development will involve more work and more specialists. Because the study is carried out before you commit to anything else, the fee is usually a small fraction of the overall project cost, and it can easily save many times that amount by steering you away from mistakes.

If you would like a figure for your own project, get in touch with our team and we will be happy to explain what is involved and give you a clear price.

Common Mistakes to Avoid

We see the same few problems time and again. The first is treating the study as a formality. If you have already decided to go ahead whatever the answer, you lose much of the value. The second is relying on a rough budget from a builder who has not seen the site. The third is ignoring the planning position until late on. And the fourth is forgetting the costs around the build, such as professional fees, surveys, legal costs and contingency, which can add up quickly.

A good feasibility study deals with all of these at the start. It gives you a realistic view of the whole project, not just the building work.

A Simple Example of a Feasibility Study in Practice

Imagine a homeowner in Hampshire who wants to add a two-storey extension and a new kitchen. They have a budget in mind and a rough idea of the design, but they are not sure it will be allowed or whether the money will stretch far enough.

A feasibility study would check the plot and the planning position, work out a realistic cost per square metre, and allow for fees, surveys and a sensible contingency. It might show that the full design would overshoot the budget by a fair margin, but that a slightly smaller scheme, or a different layout, would fit comfortably. The owner can then choose with the numbers in front of them, instead of finding out halfway through the build.

Feasibility Study vs Other Early Appraisals

People often confuse a feasibility study with other early documents. A cost estimate puts a figure on a defined design, while a feasibility study tests whether the whole idea works, including the site, the planning and the risks. A planning application deals only with whether permission can be granted. A building survey looks at the condition of an existing property. A feasibility study can draw on all of these, but its job is bigger: to give you one clear answer on whether the project is worth doing, and how to do it well.

That is why many of our clients start here. It lays the foundation for everything that follows, from design and tendering to the build itself, and it keeps the project grounded in facts from the very first day.

Frequently Asked Questions

How long does a feasibility study take?

For a simple project it can be a matter of days or weeks. Larger schemes take longer, particularly if specialist surveys or planning advice are needed. We will give you a realistic timescale at the outset.

Do I need a feasibility study for a small extension?

Not always, but it can still help. A quick check of the budget, the planning position and the main risks can save you from an expensive surprise, even on a modest project.

Can a feasibility study help me get funding?

Yes. Lenders and investors want evidence that a project has been properly tested. A professional study, with clear costs and risks, strengthens your case.

What happens if the study says the project is not feasible?

That is a useful result, not a failure. It means you have avoided spending money on something that would not have worked. Often the report also suggests changes that could make the idea viable.

Talk to Peters Cost Consultants About Your Project

Whether you are weighing up a first extension or a major development, a feasibility study gives you the facts you need before you commit. We are based in Portchester and work with clients across Hampshire and the UK, and we are always happy to talk through an idea with no pressure.

To discuss your project, contact the team or take a look at the rest of our guides on our home page.