What should a garage conversion cost in the UK in 2026?

A single garage conversion runs £10,500 to £15,000 at the basic end, £14,500 to £19,800 mid-range, and £19,800 to £32,000 for premium (bathroom, kitchenette, full integration). A double garage is £16,200 to £27,000 mid-range, up to £61,200 premium. Per m² runs £1,000 to £1,500. See the garage conversion cost guide for the full breakdown.

Why are some garage conversion quotes under £8,000?

Because they are pricing a refurbishment, not a habitable-room conversion. A quote at that level usually skips floor insulation, treats the garage door infill as a quick blockwork job rather than a structural opening, and does not extend the central heating. It will not pass Building Regulations, and when you sell the house the buyer's solicitor will ask for the certificate you do not have.

Do I need planning permission?

Most garage conversions in England fall under Permitted Development if the footprint does not change and the property is not listed, in a conservation area, or under an Article 4 direction. Building Regulations approval is separate and almost always required for the habitable-room conversion. A fair quote handles Building Control either by including the liaison or by being explicit that the application is your responsibility.

Integral or attached: does it affect the quote?

Yes, by 15 to 25%. An integral garage (under the main roof, sharing walls with rooms above) is cheaper to convert because the shared walls are already insulated and the link into the house is a doorway. An attached garage (separate roof, abutting the house) has single-skin external walls, a roof that needs insulating from scratch, and a load-bearing wall to open through.

What is normally left out of a garage conversion quote?

The Building Regulations application fee (£300 to £600 to the council, not the contractor), structural calculations from an engineer (£500 to £1,200) if any walls are being removed, central heating extension (radiators, pipework, boiler capacity check), an upgrade to the consumer unit if the garage was on a sub-circuit, floor insulation, and final decoration to a specific colour scheme. Carpet or vinyl finish is often a separate quote.

Is my garage conversion quote fair? A UK price-sense check

How to read a UK garage conversion quote: refurb vs habitable-room build, the Building Regs path, the seven jobs the price should cover, the lines often missing, and the red flags that mean the quote needs a second look before you sign.

A UK garage mid-conversion, with new stud walls, insulation, and the door opening bricked up. — Photo by Modunite Ltd on Unsplash

The hardest thing about a garage conversion quote is that the same words can describe two different jobs. A £7,000 quote is pricing a refurbishment: plasterboard the walls, paint the floor, hang a door. A £15,000 quote is pricing a habitable-room build: floor insulation, walls and roof to Building Regs, structural infill of the old door opening, new heating, Building Control sign-off. Both can be labelled "garage conversion" and neither is wrong. They are pricing different jobs.

This guide is a checklist to read a garage conversion quote line by line. For the price bands by tier and size, start with the garage conversion cost guide. For the general method, see how to compare builder quotes.

Typical price, so you have a benchmark#

In 2026, a single garage conversion (15 to 18 m² internally) is £10,500 to £15,000 basic, £14,500 to £19,800 mid-range, and £19,800 to £32,000 premium. A double garage (30 to 36 m²) is £16,200 to £19,800 basic, £19,800 to £27,000 mid-range, up to £61,200 premium. Per m² runs £1,000 to £1,500 for a standard build.

If your quote sits well below the basic band, it is almost certainly the refurb-vs-build problem above. If it sits well above premium, the explanation is usually a bathroom or a structural link to the main house, and that should be visible on the quote as a separate line.

The refurb-vs-build trap#

This is the single biggest source of confusion in garage conversion quotes. A refurb price and a build price can both be labelled "garage conversion" and differ by £8,000 on the same square metre count. The giveaway is what is on the page:

Refurb price: plasterboard, paint, a door. No floor insulation, no Building Control path, no heating extension, no structural calculation for the door infill.
Build price: all seven categories of work below, with Building Control liaison either included or explicitly named as the homeowner's responsibility.

A quote that does not address the Building Regs side has priced the refurb, regardless of what the headline says.

What a fair garage conversion quote should itemise#

A reasonable garage conversion quote covers seven categories, each with a number against it:

Floor: raise the level, add insulation to Part L, screed flat for finished flooring.
Walls: stud-and-insulation inner skin on single-skin garage walls, plasterboarded, skimmed.
Roof or ceiling: insulate between rafters or above the ceiling line, board and skim.
Garage door infill: brick or block up to the new opening, lintel above, render or brick-match the external finish.
Electrics: new circuits, sockets to current spacing, lighting, Part P-certified.
Heating: extension of central heating (radiators, pipework, boiler capacity check) or a named electric alternative.
Internal finishing: skirting, architrave, internal doors, decoration.

It should also include the Building Control path, the structural engineer's fee (£500 to £1,200) if any walls are being removed, and a note on whether the existing consumer unit will carry the new load.

A single lump sum that says "garage conversion, £12,000" tells you none of these. See how to read a builder's quote for the general format you should expect.

What is typically excluded#

Items that often quietly fall outside the headline price:

The Building Regulations application fee (£300 to £600, council fee, not contractor).
Structural calculations from a structural engineer (£500 to £1,200) if any load-bearing wall is being opened.
Boiler capacity upgrade if the existing boiler cannot handle the additional heat load.
Mains drainage connection if a bathroom or kitchenette is being added and the garage was not previously plumbed.
Carpet, vinyl, or tile finish to the floor.
Final decoration to a specific colour scheme; most quotes assume "white ceiling, magnolia walls".

For the broader pattern across trades, see hidden costs in builder quotes.

Red flags specific to garage conversions#

Priced as a refurb, not a build. Under £10,000 for a single garage is almost always the refurb price.
No Building Control path on the quote. Either the contractor handles it or you do, but someone has to.
No floor insulation in the spec. Garage floors are uninsulated concrete sloping toward the door. Skipping insulation fails Part L.
No heating extension or named alternative. A habitable room without heat will be cold and will cost more to retrofit later.
Single-glazed window in the new opening. Saves £200 today, fails Building Regs, and means a colder room for 25 years.
"No structural work needed" without an engineer. Removing a garage door is structural. The lintel above the new opening has to take the load the door frame was carrying.
No mention of how the front infill is finished. "Build up opening with blockwork" is half the job. The render or brick-match should be on the page.
Deposit above 15%. Garage conversions sit in the £10k to £30k range where a high deposit is the contractor using your money for cashflow.

For the general red-flag pattern, see signs of a rogue builder.

Before you sign#

Is the tier total inside the bands above for your garage type?
Is the Building Control path explicit, either included or named as your responsibility?
Are all seven categories of work on the page with numbers (floor, walls, roof, infill, electrics, heating, finishing)?
Is the structural engineer's fee included if any wall is being opened?
Is the front infill external finish specified (render, brick-match)?
Is the deposit at 15% or less, paid by credit card if between £100 and £30,000?
Is the total in the typical band for your garage size and tier?

If three or more of these are unclear, the quote is not ready to be compared against another. Get the missing items in writing before you decide.

The shortcut#

Running this comparison by hand means knowing per-m² rates, Building Regs parts, structural engineer fees, and consumer unit upgrade costs. Check the Quote does that part for you: paste or upload your garage conversion quote and we check every line against current UK rates, flag which of the seven categories are missing, and run a Companies House check on the contractor. Your first check is free.

Got a quote you want checked?

Paste any UK contractor quote and Check the Quote compares every line item against current market rates, flags missing scope, and runs a Companies House check on the contractor. Free on your first project.

Check a quote

Frequently asked questions

What should a garage conversion cost in the UK in 2026?: A single garage conversion runs £10,500 to £15,000 at the basic end, £14,500 to £19,800 mid-range, and £19,800 to £32,000 for premium (bathroom, kitchenette, full integration). A double garage is £16,200 to £27,000 mid-range, up to £61,200 premium. Per m² runs £1,000 to £1,500. See the garage conversion cost guide for the full breakdown.
Why are some garage conversion quotes under £8,000?: Because they are pricing a refurbishment, not a habitable-room conversion. A quote at that level usually skips floor insulation, treats the garage door infill as a quick blockwork job rather than a structural opening, and does not extend the central heating. It will not pass Building Regulations, and when you sell the house the buyer's solicitor will ask for the certificate you do not have.
Do I need planning permission?: Most garage conversions in England fall under Permitted Development if the footprint does not change and the property is not listed, in a conservation area, or under an Article 4 direction. Building Regulations approval is separate and almost always required for the habitable-room conversion. A fair quote handles Building Control either by including the liaison or by being explicit that the application is your responsibility.
Integral or attached: does it affect the quote?: Yes, by 15 to 25%. An integral garage (under the main roof, sharing walls with rooms above) is cheaper to convert because the shared walls are already insulated and the link into the house is a doorway. An attached garage (separate roof, abutting the house) has single-skin external walls, a roof that needs insulating from scratch, and a load-bearing wall to open through.
What is normally left out of a garage conversion quote?: The Building Regulations application fee (£300 to £600 to the council, not the contractor), structural calculations from an engineer (£500 to £1,200) if any walls are being removed, central heating extension (radiators, pipework, boiler capacity check), an upgrade to the consumer unit if the garage was on a sub-circuit, floor insulation, and final decoration to a specific colour scheme. Carpet or vinyl finish is often a separate quote.

Last updated: 8 June 2026

Sources cross-referenced: