Budgeting for your Home Project: What to Plan For

Whether you’re planning a home extension, renovation, or a brand new house, one of the first (and most important) questions is:

“What will it cost?”

The truth is, it depends …on size, site, materials, and finishes. Understanding the key components of your budget will help you feel informed and in control from the very beginning.

Here’s a simple breakdown to help you plan:

Construction Costs

This is the biggest slice of your budget…the actual building work. Your builder may give you a cost per square metre, but this can vary depending on complexity, finish level, and access to the site.

Keep in mind:

Renovations and extensions can cost more per m² than new builds due to complexity.
Bespoke details or high-spec finishes will push up costs.

Professional Fees

These typically include:

Architect (like me!) – design, drawings, permissions, project management
Structural engineer – for anything involving structure
Energy/sustainability consultant – if needed
Quantity surveyor – helpful for larger budgets

Fees usually represent 10–15% of the total project cost, depending on the level of service and complexity.

Statutory Fees

These are paid to your local authority:

Planning application fee
Building Warrant application fee (based on the value of work)

These are relatively small parts of the budget but must be factored in.

Contingency Allowance

Unexpected things do happen, especially with renovations.

I recommend setting aside at least 10%–15% of your total budget as a contingency fund. That way, if you hit a hidden issue or decide to upgrade a finish, you’ve got breathing room.

Provisional Sums

These are allowances for things not fully decided when pricing — for example:

A £10,000 provisional sum for kitchen units
A £4,000 provisional sum for floor finishes

Once you make firm choices, these figures are adjusted (up or down). It’s a common part of the process, but it’s worth understanding early so you don’t get caught out.

A Final Tip

Bring your architect into the budget conversation early. I can help align your ambitions with what’s achievable — and suggest creative ways to get the best outcome for your investment.

Let’s make your home work harder for you — with a clear, thoughtful plan.