Home Budget Guide

One of the hardest questions at the start of a renovation, extension or new-build home is knowing what budget is realistic.

Accurate costing needs drawings, specification, consultant input and a proper understanding of the site. But before you get to that point, a broad early-stage sense check can be very useful.

This guide is designed to help you understand the likely scale of budget involved, so you can start to align your brief, ambitions and expectations before committing to the next stage.

  • This guide is here to give you an early sense of the likely scale of your project. You do not need exact figures at this stage. Approximate areas and a few sensible choices are enough to get a useful starting point.

    Start by choosing the project type that feels closest to what you are planning. If your project includes more than one kind of work, such as an extension and changes to the existing house, choose Extension and/or refurbishment and then fill in the relevant areas below.

    For the area boxes, leave anything blank that does not apply. If you are planning a kitchen extension, enter the approximate new extension area. If you are also changing part of the existing house, add the approximate area being refurbished. For a loft conversion or roof extension, use the loft / roof extension box. If the roof itself is also being significantly repaired, insulated or rebuilt, you can add a roofing allowance in the optional section.

    The refurbishment scope helps the guide understand how much work is likely within the existing house. Choose Light refurbishment for decorating, finishes and limited changes. Choose Moderate refurbishment for more involved updates, layout changes, kitchen or bathroom upgrades and some services work. Choose Significant refurbishment where the project includes major changes, structural work, insulation upgrades or wider replacement of plumbing, heating or electrics.

    The finish level sets the overall quality assumption. Choose High quality architectural finish for a design-led project with carefully selected, durable materials, better glazing, well-considered details and good-quality fixtures. Choose Bespoke / premium finish where the project is likely to include more specialist finishes, premium glazing, fitted joinery, crafted details or a higher level of design coordination.

    The optional section is there to help include known items that can make a meaningful difference to the budget, such as kitchens, bathrooms, glazing, joinery, external works, roof improvements, cladding, air conditioning or low-energy upgrades. You can leave this section blank if you are not sure yet.

    The guide will show an estimated construction / works budget first. It will then show the wider total project budget, which may include professional fees, consultants, statutory fees, VAT and contingency, depending on the options you select.

    The result is not a quote or a fixed cost. It is intended to help you understand the likely order of cost, test whether your brief and budget are broadly aligned, and decide whether it would be useful to talk through the project in more detail.

1

Project basics

Choose the closest project type and add the main areas affected.

Choose the closest overall route. Basements and landscape / external works are treated as add-ons within the wider project.
Approximate new ground-floor extension area in m².
For two-storey extensions. Leave blank if not applicable.
For loft conversions or roof extensions.
Approximate existing floor area affected in m².
For garage conversion work forming part of a wider project.
Only include areas forming part of the project.
Basement work varies heavily due to waterproofing, drainage, structure, access, temporary works and ground conditions.
Light: finishes and small changes. Moderate: layout, kitchen/bathroom and some services changes. Significant: structural work, insulation, services replacement or deeper retrofit.
2

Finish, sensitivity and service

Select the finish level and which architectural stages to include. We will advise if formal pre-application advice is needed.

A sensible baseline for a well-considered residential project. Assumes durable materials, good glazing, carefully chosen fixtures and clear detailing, without assuming everything is bespoke or premium.
Fees are stage-based: fixed early stages, Stage 4A as a percentage of net construction cost, and separate monthly site options.
3

Optional allowances

Add known client-selected items, services upgrades or external works. Leave blank where unknown.

Use this where the kitchen is likely to be a significant part of the budget. If the kitchen is supplied separately, leave this out or choose a lower allowance.
Use this for sanitaryware, tiling, fittings and bathroom upgrades beyond the general refurbishment allowance.
Use this for larger sliding doors, rooflights, bespoke glazing or higher-performance windows beyond normal replacement windows.
Use this for reroofing, external insulation, overcladding, new cladding, significant rooflights or specialist external finishes.
Use this for fitted storage, window seats, wardrobes, utility joinery, media walls, studies, boot rooms or bespoke fitted furniture.
Use this for patios, terraces, steps, paths, external levels, garden walls, driveways, drainage, boundary works or garden areas.
External works often affect levels, drainage and construction sequencing. Substantial works may need specialist design or contractor input.
4

View your budget guide

This is a broad early-stage guide, not a quotation or cost plan.

Contingency is optional in this guide, but often sensible for refurbishment work and older buildings.

Your early-stage project budget guide

Estimated construction / works budget, before VAT£—
Likely total project budget£—
Fee calculation base£—
Architectural fees ex VAT£—
Construction supportSeparate

What the figures mean.

This guide gives you a broad early-stage budget range to help you sense-check the scale of your project. It is not a quotation, cost plan or professional fee proposal.

Every project needs to be reviewed individually. The right budget will depend on the property, planning context, brief, specification, consultant input, site conditions and the level of architectural support you would like through the process.

If the range feels broadly realistic, we would be happy to talk it through with you. A short initial conversation can help identify whether your brief and budget are aligned, where the main risks may be, and what the next sensible step should be.

Home projects involve a lot of decisions. Our role is to help make the process clearer, better coordinated and less overwhelming.

  • “They listened carefully to what we wanted and showed great flexibility and patience in the face of our lack of experience and indecision! Frances was a pleasure to work with and comes very highly recommended.”

  • “From the very start of the process both Simon and Frances worked extremely hard to create a vision of a beautiful family home situated in a lovely surrounding garden.They offered advice and support too which was all gratefully received as this is a huge undertaking both financially and emotionally too. Fantastic service.”

  • “Very happy with the work of Sharpe Architecture. Frances saw our project through from concept to completion, built a good working relationship with the builder but also pushed back when construction was not as planned or expected. Overall 10/10.”

Let’s talk about your project.

Sharpe Architecture – RIBA Chartered Architects in Tunbridge Wells, Kent

Email: hello@sharpearchitecture.co.uk
Phone: 01892 527 329

Whether you’re planning an extension, a new build or a renovation, we’d love to hear about your project. Use the contact form below to give us a quick overview of what you’re planning. Once we receive your message, we’ll get back to you promptly to arrange a no-obligation discussion to explore how we might work together.

Thanks for considering Sharpe Architecture. We look forward to talking with you soon.