Garage conversion plans and building regulations

Turning an attached or integral garage into a bedroom, office or bigger kitchen is one of the cheapest ways to add space. Auto Builder draws the garage as it is, then the new room: the wall and window that replace the garage door, new doors through to the house, and the inside layout.

Click + New plan, choose Whole-house renovation and upload your floor plan. Keep the garage as existing, then add the new wall, window and doors as proposed.

Do I need planning permission?

Usually not, as long as the work is inside the existing garage and the building doesn't get bigger. Replacing the garage door with a wall and window in matching materials is normally allowed. Check first if:

• Your house is on a newer estate. Many permissions include a condition that removes permitted development rights or keeps the garage for parking.
• The house is listed, in a conservation area, or covered by an Article 4 direction.
• The garage is detached and you want to live or sleep in it as a separate home. That is a change of use and needs permission.

If you aren't sure, apply for a Lawful Development Certificate.

Building regulations

Turning a garage into a room people live in always needs building regulations approval. The main points:

• Foundations: the new wall in the old door opening needs a foundation. The beam over the opening may only be designed to carry the door, so have it checked.
• Damp: a damp-proof course in the new wall, linked to a damp-proof membrane under the new floor. Garage floors are often lower than the house, so the floor is usually raised.
• Insulation: new floors, walls and roofs must meet the energy rules for new work in an existing home. That is about 0.18 W/m²K for walls and floors and 0.15 for roofs, with windows and doors about 1.4.
• Ventilation: an opening window big enough for purge ventilation, plus trickle vents or another background ventilator.
• Fire safety: a ground-floor room should open onto a hall leading to an exit, or have an escape window. Add a mains-powered smoke alarm linked to the others in the house.
• Electrics and heating by a registered installer, or approved by building control.

Drawings you need

• Existing and proposed floor plans of the garage and the rooms next to it.
• Existing and proposed front elevation showing the garage door replaced.
• A section through the new floor and wall showing insulation, the damp-proof course and membrane, and the foundation.

Auto Builder makes the plans, elevations and 1:50 section with a building regulations specification.

Questions