Double The Space, Endless Possibilities

Converting a double garage (approximately 30m²) gives you a footprint similar to a small apartment. This opens up possibilities that single garages simply can't offer. From expansive open-plan kitchen diners to fully self-contained "granny annexes" with their own entrance and bathroom.

Double garage converted to kitchen diner

Popular Double Conversions

The Annexe: Bedroom, en-suite, and kitchenette for elderly relatives or older children.
Kitchen Extension: Knock through to the main house to create a massive kitchen-diner hub.
Multi-Purpose: Split the space—keep one side for storage/car and convert the other into an office.

Specific Challenges for Double Conversions

Opening up a large space requires careful structural planning. Here is how we handle it.

Central Pillar Removal

To create one large room, we often remove the central brick pillar and install a heavy-duty steel beam (RSJ) to support the roof load above.

Floor Leveling

Double garages often have a slope for drainage. We use self-leveling compound or a suspended timber floor to ensure a perfectly flat finish.

Wide Openings

Replacing two garage doors with a large window or bi-fold doors requires matching brickwork and ensuring the lintels are sufficient.

Double Garage Conversion Costs

Price Estimates

A full double garage conversion typically costs between £25,000 to £35,000+ depending on the finish.

If you are creating a self-contained annexe with a bathroom and kitchenette, costs will be at the higher end due to the plumbing and partition work required.

What Affects The Price?

Steel Beams: Removing the central pillar requires calculations and steel installation.
Plumbing: Adding a bathroom or kitchen requires connecting to the main soil stack.
Windows/Doors: Large bi-fold doors are a premium feature that add cost but look amazing.

Common Questions

Can I keep half the garage for storage?

Yes, "Part Conversions" are very popular. We build a fire-rated partition wall down the middle, converting one side into a room while keeping the other side for your car or storage.

Do I need planning permission for an annexe?

Usually, if it's for family members (ancillary use), it falls under permitted development. However, if you plan to rent it out as a separate dwelling, you will need planning permission. We advise checking with the council.