A garage conversion turns an integral or attached garage into a warm, habitable room by insulating the floor, walls and ceiling, replacing the garage door with a wall and window, and adding heating, lighting and finishes.
We arrange a garage conversion for homeowners in Thamesmead and the wider London. The job is planned, priced and managed by us and carried out by tradespeople engaged under our contract, so there is one agreement and one contact. On a typical home the work takes 2–6 weeks on site, and guide pricing in London is £15,500–£36,500, VAT included.
- Guide price
- £15,500–£36,500 inc VAT
- Time on site
- 2–6 weeks on site
- Postcodes
- DA17, DA18, IG11, SE2 and SE18
- Planning rules
- England
- Local area
- Greater London
- Survey
- Free, with a written quote
Garage conversions prices in Thamesmead
Budgeting for a garage conversion in Thamesmead? The numbers below include VAT and are adjusted for London, where costs are about 30% above the national guide. The headline range is £15,500–£36,500. Nothing is final until we have measured up at a free survey and agreed the specification with you.
| Type of job | What it usually involves | Guide in Thamesmead |
|---|---|---|
| Integral single garage | A garage within the house footprint, with sound walls and a roof already in place. | £13,000–£23,500 |
| Attached single garage | A garage beside the house that may need roof, wall or floor upgrades. | £18,000–£32,500 |
| Double or detached garage | A larger or separate building, often with a shower room or kitchenette. | £28,500–£58,000 |
What moves the price up or down:
- Garage type: integral, attached or detached
- Condition of the floor, walls, roof and foundations
- Heating method and ventilation for the new room
- Window and door choices and the level of finishes
Scope of the work
- Infilling the garage door opening with insulated wall and new window
- Foundation checks under the door opening and footings where needed
- New internal door or opening into the house
- Electrics, heating and ventilation by qualified trades, with certificates
- Plastering, skirting and decoration-ready finish
- Building control inspections and completion certificate
Building in Thamesmead
London's housing is dominated by Victorian and Edwardian terraces, often in yellow London stock brick, with Georgian terraces in central districts and mansion blocks across many inner areas. Outer boroughs have large belts of interwar semis, and there are extensive post-war council estates. Many houses have been split into flats, and conservation areas are widespread.
London Clay shrinks and swells with the seasons, and street trees close to houses can contribute to movement, which affects foundation design.
None of this holds for every street in Thamesmead, which is why we look at your actual house before pricing a garage conversion rather than assuming from its age alone.
Permissions for a garage conversion in Thamesmead
As Thamesmead is in England, read the following with that system of planning and building control in mind. We check what applies to your house with the council before you receive a quote.
In England, converting an attached or integral garage into a room usually needs no planning permission, unless a planning condition on your estate has removed permitted development rights (common on newer houses). Changing the garage door to a wall and window is generally fine.
Building Regulations approval is needed: foundations for the infill wall, a damp-proof course, insulation, ventilation and fire safety.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
From survey to handover
A visit to your home
Book a visit and we'll come to you. The survey covers measurements, the state of what's there now and any obvious constraints, so the price that follows is based on your actual home, not an average.
Quote in writing
After the survey we send a quote for a garage conversion that fixes the price for the scope we've agreed. If you want to change materials or scope, we revise it in writing before anything is booked.
Plan and prepare
With the quote agreed, we book the work in and handle preparation: permissions where needed, building control notifications, material orders and access arrangements for your Thamesmead property.
On site to finish
On site, the agreed plan is followed and any change is put in writing first. At completion we do a final clean, go through the snagging list with you and leave you with the relevant documents.
How we work
Garage conversions in Thamesmead: questions
Do I need planning permission in Thamesmead?
It depends on the work, the size of the project, your property type and whether the building is listed or in a conservation area. Thamesmead is in England, so England's rules apply. Many smaller jobs need no planning application, but some still need building control approval. We check what applies to your address before quoting.
Can I keep some storage space?
Many people keep part of the garage for storage by building a dividing wall, leaving a smaller store at the front behind the existing door and converting the area behind into a room or utility. This keeps the look of the house unchanged and gives you somewhere for bikes and tools. The converted part still needs the same insulation, ventilation and fire separation.
What happens at the survey?
We visit your home at a time that suits you, look at the area involved, take measurements and check access, condition and any services that might be affected. We talk through what you want from a garage conversion, explain the options and answer questions. There is no charge and no obligation; afterwards we send a written quote.
Will losing the garage affect parking?
Losing a garage can matter if your street has parking pressure or your property deeds or planning conditions require off-street parking. Many garages are too narrow for modern cars, so in practice the driveway often provides the parking anyway. We check for planning conditions affecting the garage before quoting. If you need extra parking, we can also price a driveway extension.
Do I need planning permission for a garage conversion?
Whether a garage conversion needs planning permission depends on the works, your home's location, whether it is listed or in a conservation area, and which UK nation you are in. In England, converting an integral or attached garage is often permitted development where changes are mostly internal, unless a planning condition has removed those rights, which is common on newer estates. We check what applies before quoting.
Also covering areas around Thamesmead
Addresses in DA17, DA18, IG11 and SE2 are all covered for Thamesmead, along with Barking, Welling and Becontree close by. Give us your postcode when you get in touch and we will confirm the details.

