Extension, Loft Conversion or Garage Conversion: How to Choose
Three of the most common ways to add space to a house each suit different properties and priorities. Here's how to weigh them up before committing to a design.
Short answer: an extension usually delivers the most new floor space but the most disruption and the highest cost per square metre when foundations are involved; a loft conversion adds a bedroom or two with limited footprint impact but depends on roof pitch and head height; a garage conversion is often the fastest and least disruptive if the garage is no longer used for parking.
| Option | Best suited to | Typical planning route | Key constraint |
|---|---|---|---|
| Rear or side extension | Households needing a larger kitchen-diner or ground-floor living space | Often permitted development within limits; full permission for larger schemes | Garden depth and boundary conditions |
| Loft conversion | Adding one or two bedrooms without extending the footprint | Often permitted development within volume limits | Roof pitch and available head height |
| Garage conversion | A home office, playroom or extra bedroom where the garage is unused for parking | Usually falls under permitted development or a minor application | Existing garage floor level and insulation upgrade needed |
Questions worth asking before you decide
- Do you need the extra space to be a bedroom (which has specific fire escape and window requirements) or flexible living space?
- How much disruption can the household tolerate, and for how long?
- Is off-street parking important enough that losing a garage would cause a problem?
- What does the roof pitch and existing head height allow for a loft conversion, if that's an option?
Getting a realistic comparison for your property
The right answer depends on your specific house, plot and budget rather than a general rule. We can walk through options for your property at the initial site visit, including a realistic view of cost, disruption and planning route for each.
Planning and Building Regulations rules are set nationally but applied locally, and they change from time to time. This article reflects general guidance correct at the time of publication — always confirm the current position for your specific property with your local planning authority or at gov.uk and the Planning Portal before relying on it.
Talk to us about your project
Tell us about the property and what you have in mind. We'll arrange a site visit and provide a written, itemised quotation.