Over-Garage Extensions
First-floor rooms built above your attached garage, a cost-effective way to add an extra bedroom, en-suite or home office without losing any garden space, built to the highest standards across Stockport and Cheshire.
At a Glance: Over-Garage Extensions
- Typical cost: £30,000 to £55,000
- Typical timeline: 8 to 14 weeks on site
- Planning permission: Often permitted development, but existing foundations must be assessed
- Areas covered: Stockport, Manchester, Cheshire
- Free site survey: Yes
The Smart Way to Add a Room Above Your Garage
An over-garage extension is one of the most cost-effective ways to add a room, because the foundations and walls are already in place. It's the ideal route to an extra bedroom, en-suite or home office without sacrificing a single metre of garden. We've built them across Stockport, Cheadle, Wilmslow and Cheshire.
Build upward over the garage, your outdoor space stays untouched
Existing walls and footprint keep costs down versus a full extension
Many fall within permitted development rights
Popular Over-Garage Room Ideas
Every over-garage extension we build is unique. Here are the most popular ways our clients use the new first-floor room above their garage.
Extra Bedroom
Turn the space above your garage into a spacious double bedroom, a guest room, a growing teenager's retreat or a fourth bedroom that adds real value to your home.
Bedroom with En-Suite
Combine the new bedroom with a private en-suite bathroom to create a self-contained master or guest suite, one of the most sought-after features for buyers.
Home Office
A quiet, purpose-built home office set apart from the main living areas, properly insulated and wired for a dedicated, distraction-free place to work.
Dressing Room
Use the extra first-floor space as a walk-in dressing room or wardrobe, freeing up your existing bedrooms and adding a touch of everyday luxury.
Building Over Your Garage
Building on top of an existing garage brings its own considerations. Here are the three things that matter most for a safe, seamless over-garage extension.
Foundation Assessment
Existing garage foundations are often shallower than those required to carry a first floor. A structural engineer inspects them first, and where needed we underpin or strengthen the foundations so they can safely bear the extra load. This is the single most important step in any over-garage build.
Matching Brickwork
To make the extension look like it has always been part of the house, we source brick and render to match your existing elevations, tie the new roof into the main roofline and align windows with the rest of the property for a seamless, integrated finish.
Insulation & Comfort
Because the room sits above an unheated garage, proper floor, wall and roof insulation is essential for warmth and quiet. We install high-performance insulation and heating so the new room is comfortable all year round, meeting current building regulations.
Build Without Planning Permission
Many over-garage extensions can be built under permitted development rights, meaning no planning application is needed, saving you time and money. Here are the key rules your extension must meet:
The extension must not be higher than the highest part of the existing roof, and upper-floor side windows must be obscure-glazed and non-opening below 1.7m to protect neighbours' privacy.
Where the addition is within 2 metres of a boundary the eaves height is limited to 3 metres. Extensions to the side or to the principal elevation facing a highway have tighter restrictions.
The total footprint and volume added by extensions must stay within permitted development allowances for your property type, so the addition remains subordinate to the original house.
Materials used in the extension must be similar in appearance to the existing dwelling. No verandas, balconies, or raised platforms are permitted under PD rights.
Conservation areas, listed buildings, and some housing estates have restricted PD rights. We check your eligibility, and assess whether your garage foundations can carry a first floor, as part of our free site survey.
Week-by-Week Build Timeline
Here's a typical timeline for an over-garage extension, so you know exactly what to expect at each stage of the project.
Survey & Foundation Strengthening
Structural engineer's inspection of the existing garage foundations, followed by any underpinning or strengthening needed to carry the first floor.
Walls & Floor Structure
New first-floor walls raised on the strengthened base, steel beams and the insulated floor structure installed over the garage. Openings formed for windows.
Roof & Weatherproofing
Roof structure tied into the existing roofline, insulation and covering installed. Windows and doors fitted, and the extension becomes watertight.
First Fix Services
Electrical wiring, plumbing for any en-suite, and heating pipework installed before plasterboarding the new room.
Plastering & Second Fix
Internal walls plastered, any en-suite fitted, sockets and switches installed, flooring laid and staircase or landing completed.
Finishing & Handover
Final decoration, snagging, building control sign-off, and handover. Matching external brickwork and render completed for a seamless finish.
Over-Garage Extension FAQs
Everything you need to know about over-garage extensions, answered by our team.
Can my garage take a first-floor extension?
In many cases yes, but it must be verified first. The existing garage foundations and walls were often not built to carry the weight of a first floor. A structural engineer inspects the foundations, and where they are too shallow or narrow we underpin or strengthen them so they can safely bear the extra load. This assessment is part of our free site survey.
Do I need planning permission for an over-garage extension?
Many over-garage extensions fall under permitted development, provided the addition does not exceed the height of the existing house, stays within the volume and boundary limits, and uses matching materials. Conservation areas, listed buildings and homes where PD rights have been removed require full planning permission, which we manage on your behalf.
Will I lose the garage below the extension?
No. Building above the garage keeps the ground-floor garage or storage space intact. We add a first floor on top of the existing structure, so you gain a new room upstairs without losing parking, storage or any garden space, which is exactly what makes this such a space-efficient way to extend.
How much does an over-garage extension cost?
Over-garage extensions in the Stockport and Cheshire area typically range from £30,000 to £55,000, depending on the size, whether the foundations need strengthening, and the internal specification such as adding an en-suite. We provide a fixed-price quotation after our free site survey.
Do I need a structural engineer for an over-garage extension?
Yes. A structural engineer must verify that the existing garage foundations can bear the extra load of a first floor, and specify any underpinning, steel beams and floor structure required. This is a building regulation requirement and essential for a safe build. We arrange all structural engineering, and strengthen the foundations where needed, as part of our service.
Frequently Asked Questions
Can my garage take a first floor extension?
In many cases yes, but it must be verified first. The existing garage foundations and walls were often not designed to carry the load of a first floor. A structural engineer inspects the foundations, and where they are too shallow or narrow we underpin or strengthen them so they can safely bear the extra weight. This assessment is part of our free site survey.
Do I need planning permission for an over-garage extension?
Many over-garage extensions fall under permitted development, provided the addition does not exceed the height of the existing house, sits within the volume and boundary limits and uses matching materials. Conservation areas, listed buildings and homes where PD rights have been removed require full planning permission, which we manage on your behalf.
Will I lose the garage below the extension?
No. Building above the garage keeps the ground-floor garage or storage space intact. We build a first floor over the existing structure, so you gain a new room upstairs without losing parking, storage or any garden space.
How much does an over-garage extension cost in Stockport?
Over-garage extensions in the Stockport and Cheshire area typically range from £30,000 to £55,000, depending on the size, whether the foundations need strengthening and the internal specification such as an en-suite. We provide a fixed-price quotation after a free site survey.
Do you offer a free quote?
Yes. The first consultation and on-site survey are completely free and with no obligation, followed by a clear itemised quote.