Turning all or part of a garage into a habitable room in England normally requires Building Regulations approval. The drawings should show how the existing space will be adapted for the intended use. A layout identifies the new room, and the sections, details and specification explain how the floor, walls, openings and services will work together.
Show What Changes at the Garage Door
If the design replaces the garage door with a wall and window, the drawing set should show the new elevation and how the opening will be closed. A section can explain the relationship between the new wall, its support, the floor and the surrounding structure. Ask the designer what is known about the existing support and whether it needs investigation. The answer can affect both the design and the builder’s price.
Explain the Floor and the Transition to the House
Ask for a section through the garage floor and the connection to the house. It should explain the intended floor level, and how the design will deal with insulation and moisture. This matters when the garage floor sits lower than the house floor, or when the designer needs to allow for insulation and floor finishes without losing useful headroom.
The rest of the package should reflect the room you are creating. A bedroom, office and utility room have different uses, and adding a sink or WC introduces a drainage question. If you plan to keep part of the garage, ask the designer to show the separation between the retained garage and the new room, and how the relevant fire and thermal requirements are addressed. Check how ventilation, heating, electrics and windows are covered in the plans or specification.
Settle the Approval Route and Fees
Planning permission and building control are separate checks. Planning Portal says internal garage conversion work that does not enlarge the building will not usually require planning permission, though restrictions and a proposal for a separate dwelling can change the position. Check the position for your property and discuss the building control route with the chosen body.
Ashbridge’s published Stage 2 design fee for garage conversion Building Regulations drawings starts at £700. Building control charges are separate. Check whether your scope also needs structural calculations and what is included in the quote. See the design package prices.
Example: Converting Half of an Integral Double Garage
A homeowner wants a quiet office while keeping the other half for parking and storage. The proposed plan labels both areas. The drawings explain the new partition and door arrangement, the office floor and the infill around the new front window. The designer asks for the support below that opening to be confirmed before finalising the detail. The homeowner can then ask builders to price the same scope.
If you know what you want to use the garage for, share a sketch and photographs with Ashbridge to scope the technical drawing pack.