Alter your garage door or windows with the structure designed first

Brick garage with its wide door opening part bricked in, a new window in the infill, a narrower door and a steel lintel

For homeowners bricking up, widening or narrowing a garage door, or adding windows and doors to a garage wall. Describe your garage and compare quotes from structural engineers.

Garage walls look simple, but they are often lighter and less carefully built than the rest of the house. An integral garage may have a bedroom directly above the door opening, carried by a beam or lintel that cannot simply be changed. Bricking up the door creates a new wall that needs foundations, a damp-proof course and insulation. Widening it means a new, stronger lintel or beam. A structural engineer works out what the existing wall and foundations carry before anything is cut or dug, designs the change, and provides what building control needs.

How a professional can help

Checking what is above the garage door: They find out whether a room, a wall or a roof sits on the lintel or beam over the opening, which decides how much of it can be altered.
Bricking up a door opening: They design the infill wall, including a foundation beneath it, the way it ties into the existing masonry, and the damp-proofing and insulation details, so the new wall performs like the old ones.
Widening or narrowing the opening: They size a new lintel or beam, check the brickwork or piers left either side and the foundations beneath them, and specify propping to hold the structure during the change.
New windows and doors in garage walls: They design the lintels and surrounds for new openings in a garage wall, including walls built a single brick or block thick, where piers or posts may be needed to keep the wall stiff.
Garage conversions: For a garage converted to living space, they review the floor, walls and roof, including any structural change the conversion needs, and coordinate with your designer’s Building Regulations drawings.
Attached, shared and detached garages: They check walls shared with the house or a neighbour, and whether the garage’s foundations and roof can take the new openings.

Is this right for you?

You want to brick up a garage door as part of converting the garage into a room.
You’re widening a garage door to fit a larger car or a modern roller or sectional door.
You want a new window or side door in a garage wall for a workshop, gym or home office.
Your integral garage has a bedroom above and you aren’t sure what holds it up.

How the project usually runs

Look at the garage: The engineer inspects the walls, the lintel or beam over the door, the roof and the floor, noting what sits above and whether the garage is attached, integral or detached.
Check the foundations: A small trial hole may be dug beside the wall to see how deep the foundations go and what they are made of, particularly before a new wall is built across the old door opening.
Design the change: The engineer designs the lintel or beam, the infill wall and its foundation, or the new opening, with calculations and a drawing your builder and building control can use.
Building control and planning: Calculations go to building control with the Building Regulations application. Planning and any neighbour notices are checked at this stage too, so none is missed before work begins.
Building the infill or opening: The builder props the wall if needed, forms the opening or infill, and completes the foundation and damp-proofing. Building control inspects the foundation trench and the finished work, and the engineer can check the new foundation and lintel before they are covered.

What affects the cost

Whether the garage is integral, attached or detached, and what it carries above.
The width of the door opening you want to widen, narrow or close up.
Whether a new foundation is needed under an infill wall, and the depth the ground and any nearby trees require.
The wall construction, since single-thickness, cavity and older solid walls need different details.
Matching brick, render or cladding on the outside, and insulating and finishing the inside.
Whether the garage is being converted to living space, which brings floors, insulation and ventilation into the scope.

Planning, Building Regulations and garage alterations

Converting a garage often doesn’t need planning permission, but some developments have a condition keeping garages for parking, and listed buildings and conservation areas can need consent. Rules differ across England, Scotland, Wales and Northern Ireland, so check with your council.
Altering the door opening or building an infill wall is structural work and normally needs Building Regulations approval, or a building warrant in Scotland, though some small detached garages are exempt. Converting to a habitable room is covered too. Structural engineers cover the whole UK.
Garages built against a neighbour’s wall, or foundations dug close to next door, can bring the Party Wall etc. Act 1996 into play in England and Wales.

Questions people ask

Does a bricked-up garage door need a foundation?

Usually, yes. Where a garage door was, there is normally no wall foundation, only a slab or threshold. A new infill wall needs its own foundation, to a depth that suits the ground, and the engineer specifies this. Building control normally wants to inspect it before it is covered.

Can I widen my garage door?

Often, but check what is above. A single-storey garage may carry only its roof, while an integral garage can support a bedroom. A new, wider lintel or beam has to carry that load, and the brickwork or piers on either side must be strong enough to take it. An engineer can tell you the widest opening your garage can take.

Do I need a lintel or beam for a new garage window?

Yes, every new opening in a wall needs something to carry the wall above it. In a garage wall that might be a standard lintel, or something stronger if a roof or floor bears on it. The engineer will specify it and check the wall around the window is stiff enough.

Is a garage conversion a structural job?

It can be. Often the structural part is the door opening, the infill wall and its foundation, and sometimes the roof. The rest, such as insulation, damp-proofing and a new floor, is covered by Building Regulations. Your designer and engineer can work together to prepare the drawings.

Will the new wall look different from the old one?

That depends on bricks, bond and finishing rather than structure, but it matters. Matching brickwork on an older house is difficult. Some owners use render, cladding or a recessed window to make the change look deliberate. Talk to your designer or builder before the structural design is finalised.

Available across the UK

Professionals cover the whole of the UK: England, Scotland, Wales and Northern Ireland. Planning and Building Regulations differ between the four nations, and your professional will work to the rules that apply where your property is.