How Much Does a House Extension Cost in Inverness?

Typical Extension Costs in Inverness

As a rough guide, a single storey rear or side extension in and around Inverness typically costs between £1,800 and £2,600 per square metre for a good mid range specification, covering foundations, blockwork, a warm roof, windows and basic internal finishes. For a typical 20 to 25 square metre kitchen extension, that works out at roughly £45,000 to £65,000 all in, before kitchen units, flooring and decorating are added.

Two storey extensions cost more in total but less per square metre of extra space, because you're sharing one roof and one set of foundations across two floors. Expect £1,600 to £2,200 per square metre, so a 40 square metre two storey addition on a 20 square metre footprint might land between £65,000 and £90,000. A simpler garden room or sunroom with less structural work can start from around £1,200 per square metre.

• Single storey rear extension (20 to 25m²): roughly £45,000 to £65,000
• Two storey extension (40m² total floor area): roughly £65,000 to £90,000
• Garden room or sunroom with bi fold doors: from around £1,200/m²
• High spec extension with large glazing, steel beams and underfloor heating: £2,800/m² or more

What Pushes the Price Up or Down Locally

Ground conditions around Inverness vary a lot, from the rock close to the surface in parts of Culduthel and Dores Road to softer, boggier ground nearer the Moray Firth and the Ness. Sloping or rocky sites often need deeper foundations or piling, which adds cost before the walls even go up.

If your property is a traditional stone built villa in areas like Crown, Ballifeary or Merkinch, matching the existing stonework, render or slate roof adds labour and material cost compared with a plain blockwork and render extension. Highland weather also pushes many homeowners towards a higher insulation and glazing spec than the minimum, which pays off in comfort and running costs but raises the build price.

• Sloping, rocky or waterlogged ground needing extra foundation work
• Matching existing stone, render or slate on older Inverness properties
• Removing load bearing walls for open plan kitchen living space, requiring steel beams
• Upgraded insulation, triple glazing and underfloor heating for the Highland climate
• Site access for machinery, particularly on narrower streets in the Old Town or hillside plots

Planning Permission and Building Warrants in Inverness

Many single storey rear extensions fall under permitted development rights in Scotland, but the rules and size limits differ from England, so it's worth getting written confirmation from Highland Council rather than assuming. If your home sits within a conservation area such as Crown, the Old Town, Ballifeary or parts of Merkinch, or if it's a listed building, full planning permission is almost always required and materials usually need to match the original.

Separately, you'll need a Building Warrant from Highland Council's Building Standards service before any work starts on site, regardless of whether planning permission was needed. This checks the structural design, insulation levels and fire safety meet Scottish Building Standards, and typically takes a few weeks to process once your builder or architect submits full drawings.

Getting an Accurate Quote and Staying on Budget

Get at least two or three detailed quotes from local builders who are used to Highland ground conditions and the Building Warrant process, rather than a single rough estimate. A proper quote should break down groundworks, structure, roofing, windows and finishes separately, so you can see exactly where the money is going and compare quotes fairly.

Agree the specification, including things like window type and flooring, before work starts, since changes mid build are one of the most common causes of extensions running over budget. It's also sensible to keep a contingency of around 10 to 15 percent of the build cost for unexpected ground conditions or price changes on materials.