Every homeowner who starts thinking seriously about an extension asks the same question first. What is it actually going to cost? It is the right place to start — and it deserves a straight answer rather than a vague "it depends."

The cost of a single storey extension varies depending on a handful of specific factors. Here is an honest breakdown of what drives the price and why the Spectra Range consistently comes in below what traditional construction would cost for the same result.

What Drives the Cost of a Home Extension

Size

Floor area is the primary cost driver. A compact rear addition costs considerably less than a large open-plan kitchen diner that runs the full width of the property. That said the Spectra Range delivers genuine economies of scale — our fixed foundation and structural costs mean that larger projects do not scale up in price the way they do with conventional builders.

Specification

The finish you choose makes a real difference to the final figure. Bifold doors, a roof lantern, underfloor heating and premium internal finishes all add to the cost — but they also add the most measurable value to your property. Our team will help you work out where your budget is best spent at the design stage.

Internal Finish

Windows, doors, flooring and internal decoration sit across a wide price range. Standard and premium specifications are genuinely different propositions and we will give you a clear picture of both options before any commitment is made.

Site Conditions

The majority of plots we work on are straightforward for our system. Occasionally restricted access, challenging ground or the presence of underground services will affect the foundation element of the cost. We identify everything that matters during your free site assessment — before a quote is confirmed and before any work begins.

Where We Work

Spectra Extensions serves a broad area centred on Milton Keynes. To the south we cover Leighton Buzzard and Woburn Sands. To the north we work across Northampton. To the west we serve Aylesbury and the surrounding Buckinghamshire villages. Closer to home our team is regularly on site across Bletchley, Wolverton, Newport Pagnell, Stony Stratford, Cranfield and Wavendon.

The approach is identical wherever we build — efficient clean construction with a fixed price and no surprises.

Why the Spectra Range Costs Less

A traditionally built extension of the same scale and finish will almost always cost more — often significantly more once the hidden additions that accumulate during a conventional build are factored in.

The RADIX screw pile foundation system removes the most expensive element of traditional groundwork entirely. No large-scale excavation, no poured concrete and no curing period. A four to five week build programme rather than three to six months means considerably lower labour costs throughout. And because the price is fixed before work starts there is no mechanism for costs to creep upward once the build is underway.

Fixed Price. No Exceptions.

The figure in your quote is the figure on your final invoice. Nothing is added, nothing is revised and there are no difficult conversations at the end of the project.

Find Out What Your Extension Will Cost

The most reliable way to get an accurate figure is a free site assessment. We will visit your property, take a proper look at what is involved and provide a full written quote — at no cost and with absolutely no obligation to proceed.

Contact Spectra Extensions today and get a straight answer on what your extension will cost.

We serve Milton Keynes and the surrounding area including Bletchley, Wolverton, Newport Pagnell, Stony Stratford, Leighton Buzzard, Woburn Sands, Cranfield, Northampton and Aylesbury.