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.
Homes across Hertfordshire vary a great deal, so we price a garage conversion only after seeing the property. Our coverage takes in Watford, Hemel Hempstead, Stevenage and St Albans and the surrounding districts. As a guide, expect £12,500–£29,500 including VAT in the East of England; the final figure depends on size, materials and access. Any permissions are checked against the rules for England before we quote.
- Guide price
- £12,500–£29,500 inc VAT
- Time on site
- 2–6 weeks on site
- Planning rules
- England
- Price level
- About 5% above the national guide
- Towns listed
- 19
- Survey
- Free, with a written quote
How much does a garage conversion cost in Hertfordshire?
What should you budget for a garage conversion in Hertfordshire? Use the figures below as a starting point. Prices in the East of England sit about 5% above the national guide, so the range here is £12,500–£29,500 including VAT. Your fixed price comes in writing once we've surveyed the property, at no charge.
| Type of job | What it usually involves | Guide in Hertfordshire |
|---|---|---|
| Integral single garage | A garage within the house footprint, with sound walls and a roof already in place. | £10,500–£19,000 |
| Attached single garage | A garage beside the house that may need roof, wall or floor upgrades. | £14,500–£26,000 |
| Double or detached garage | A larger or separate building, often with a shower room or kitchenette. | £23,000–£47,000 |
What moves the price up or down:
- Garage type: integral, attached or detached
- Condition of the floor, walls, roof and foundations
- Whether a shower room or kitchenette is included
- Window and door choices and the level of finishes
What’s included?
- Foundation checks under the door opening and footings where needed
- Damp-proof membrane, insulated floor and screed or raised timber floor
- Insulated walls and ceiling built to building regulations
- Electrics, heating and ventilation by qualified trades, with certificates
- Plastering, skirting and decoration-ready finish
- Building control inspections and completion certificate
Housing across Hertfordshire
Hertfordshire is home to the first garden cities, Letchworth and Welwyn Garden City, and the post-war new towns of Stevenage, Hatfield and Hemel Hempstead. Watford and St Albans have Victorian terraces and Georgian streets, interwar semis line the commuter suburbs, and brick-and-flint cottages appear in Chiltern villages to the west.
New-town and garden-city homes often suit extensions, window replacement and roofline renewal, though some garden-city estates have their own design guidance. Victorian terraces commonly take loft rooms and side-return extensions.
Generally dry with chalk and clay soils; clay areas can move in long dry spells, and mature trees near houses need considering for foundations.
Do you need permission in Hertfordshire?
England, Wales, Scotland and Northern Ireland each handle planning a little differently. Hertfordshire comes under England, covered below, and we raise any questions with the council before your quote is finalised.
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.
How does the job run?
A visit to your home
A free survey comes first. It gives us what we need to price a garage conversion properly, including dimensions, existing materials and access for deliveries, and gives you the chance to ask anything you like.
Your fixed price
We turn the survey notes into a written quote. The price is fixed for the specification we agree, and the document sets out materials, scope and payment stages in plain language.
Getting ready
We handle the paperwork side: checking whether planning permission or building control approval is needed, submitting applications where they are, and scheduling the trades and materials around your dates.
Build and hand over
Our trades complete a garage conversion while your point of contact keeps you updated. When everything is finished, we clear the site, take away waste and go through the result with you before handover.
How we work
Frequently asked questions
Which postcodes in Hertfordshire do you cover?
We cover WD1, HP1, SG1 and AL1, along with the rest of Hertfordshire. If your postcode is not listed, get in touch anyway: our coverage is UK-wide, and we can usually arrange a survey wherever you live. Enter your postcode in the guide-price tool or contact form and we will confirm.
How long does a garage conversion take?
A straightforward integral garage conversion usually takes two to four weeks on site. Attached garages that need roof or wall upgrades, and conversions with a shower room, typically take four to six weeks. Detached garages turned into annexes can take longer. Before work starts, allow time for drawings and building control approval. We give you a clear programme with your written quote.
Who do I deal with during the job?
One point of contact manages your project from survey to handover. They schedule the trades working under our contract, keep you updated on progress, and are the person to call with any question. You don't need to coordinate builders, electricians or decorators separately, because that is part of what we do.
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.
Will the new room be warm enough?
A converted garage can be as warm as any other room in the house, provided the floor, walls and ceiling are insulated to current standards. Garages are usually built with single-skin walls and no insulation, so this work matters. Heating can come from a new radiator on your existing system, underfloor heating or an electric heater, depending on your boiler capacity. We advise on the most suitable option.
Towns in Hertfordshire
Choose your town from the list to see how we price and plan a garage conversion in your part of Hertfordshire, including typical time on site.