How Much Does a Garage Conversion Cost in 2026?

If you’re planning a garage conversion in Rainford or St Helens, cost is usually the first question. Here’s what garage conversions typically cost in 2026, what affects the price, and real figures from jobs we’ve completed locally.

UK Average Cost of a Garage Conversion

The average cost of converting a single garage in the UK is around £14,500, with prices typically ranging from £8,000 to £25,000 depending on the type of garage and the finish you choose.

For a standard integral or attached garage of around 15 to 18 square metres, which covers most of the properties we work on in Rainford and St Helens, you’re typically looking at £10,000 to £20,000. Detached garage conversions cost more, often £20,000 to £31,000, because they need new foundations, drainage and services run out to the building.

What Affects the Price

• Size of the garage and how much floor space you’re converting
• Whether you’re adding a WC or en-suite, which means new plumbing
• Sockets, lighting and heating needed for the new room
• Structural work such as a new hallway opening, removing the garage door and adding a wall and window
• The finish level you choose, from basic plaster and paint to a fully fitted room with high end switches, lights, heating

Real Garage Conversion Costs from Rainford Buildings

Here’s what two recent garage conversions actually cost, so you can see how the numbers play out in practice:

• Plain integral garage conversion in St Helens, no WC: £12,700 + VAT (£15,240 including VAT)
• Garage conversion with an added WC in Rainford: £17,690 + VAT (£21,228 including VAT)

The main difference between these two jobs is the plumbing. Adding a WC and running new drainage typically adds £4,000 to £5,000 to a garage conversion.

What’s Included in a Typical Rainford Buildings Quote

• Garage door removal and a new wall and window in its place
• New hallway opening into the house, including lintel and door
• Full insulation, plasterboard and a skimmed finish
• First and second fix electrics
• Connection to your existing central heating or electric radiator
• Flooring, skirting and architrave
• Liaison with Building Control throughout

Getting an Accurate Quote

Every garage is different, and the figures above are a guide rather than a fixed price. The best way to know what your conversion will cost is a site visit, where we can look at the garage, talk through what you want the space to do, and give you a firm quote. Get in touch with Rainford Buildings to arrange yours.