Garden Room vs Conservatory vs Extension: Which Is Cheaper?

If you need extra space, a garden room isn’t your only option — but it’s usually the fastest and most cost-effective one. Here’s how the three compare.

Garden room

Typical cost: £14,500–£28,000+ depending on size and spec. Built on its own concrete foundation in your garden, so there’s no disruption inside your home, and often no planning permission needed at all. Build time is usually 4-6 weeks.

Conservatory

Typical cost: £15,000–£30,000+. Conservatories are attached to your house, which means more disruption during the build and often planning considerations tied to your existing structure. They can also struggle with temperature regulation — cold in winter, uncomfortably hot in summer — unless built to a high (and pricier) glazing spec.

House extension

Typical cost: from around £35,000 for a single-storey rear extension, rising with size, finish and complexity — see our extension guide prices. Many single-storey extensions fall under permitted development, but they always need Building Regulations approval, involve structural work to your existing house, and take longer — often 3-6 months including design and approval time. In return, you get extra space inside the home itself, such as a bigger kitchen-diner or an extra bedroom.

The bottom line

For home offices, studios, gyms, and similar standalone uses, a garden room typically delivers the best balance of cost, speed, and year-round comfort — without the disruption of building work inside your home. If you need more space inside the house itself, a well-designed home extension is often the better long-term investment — and we build both.

Compare our exact model pricing on the Price Guide page, or get in touch to talk through what’s right for your space.