7 Mistakes to Avoid When Buying a Garden Room.

Investing in a garden room can be a game-changer whether you’re working from home, creating a space to unwind or simply need extra space without the hassle and expense of a traditional extension. But with so many options available, it’s easy to make decisions that affect the comfort, longevity and practicality of your new space. Here are some of the common garden room buying mistakes and how to avoid them.

1. Underestimating Insulation and Year-Round Use

Not all garden rooms are created equal. Some are designed for fair weather only and become cold, damp and unusable in winter. If you want to use your garden room all year round, insulation isn’t optional—it’s essential. Look for high-quality materials and insulation in the floor, walls and roof.

When most people think of insulation, they only think about the walls and ceilings but the floor is just as important. Inadequate floor insulation will make your garden room cold and uncomfortable in the winter months.

Cosy tip: Ask about U-values and how the space will feel on a chilly January morning—not just in July sunshine.

2. Choosing the Wrong Design for Your Space

Standard, off-the-shelf designs might seem quicker or cheaper, but they often don’t suit your garden’s shape, size or orientation and may come with compromises on layout or usability. Choosing something bespoke means your garden room will be designed to fit both your space and your lifestyle.

It’s also worth thinking about what you’ll see from inside the room. Poor window placement can leave you staring at a fence or shed, rather than enjoying the full benefit of your garden. An experienced designer will consider these sight lines, angles and how you plan to use the space.

Equally, avoid rooms that are too big and dominate your garden or too small and look lost, even if they meet your functional needs. Balance is key.

Cosy tip: A bespoke garden room puts your needs first—offering better layout, natural light and views you’ll actually want to look at.

3. Overlooking the Foundations

One of the biggest issues we see is people underestimating the importance of solid foundations. Pegged and screwed bases are often used for speed and convenience, but they’re not suitable for every garden or every type of use. These bases can lead to increased movement and internal cracking over time.

A concrete base, when properly installed, offers greater stability and long-term durability. It might take longer to install, but it’s worth it in the long run.

Cosy tip: Don’t scrimp on the foundations. A garden room is only as strong as what it stands on.

4. Ignoring Planning Rules and Permissions

A garden room is a major investment, and most of the time these structures fall under permitted development. Meaning you don’t need planning permission. However, there are still important rules around size, height and distance from boundaries.

If you don’t follow these guidelines, you may be asked to alter or even remove the structure, which is an expensive and stressful outcome.

Cosy tip: Always double-check the planning regulations in your area before you build. Don’t assume it’s someone else’s job to do it.

5. Skipping the Small Print: Guarantees and Certificates

Make sure you receive a clear guarantee for the structure and an electrical certificate for the installation. Reputable companies will also use FSC-certified timbers and other quality materials but it is always worth asking.

A guarantee gives you peace of mind that the building is made to last and that any potential issues will be addressed. Without it, you could be left out of pocket for costly repairs.

Cosy tip: Always ask what’s covered under the warranty and make sure you get it in writing.

6. Forgetting to Check Reviews

Even a beautiful brochure can’t tell you how well a company communicates, installs, or responds to problems. Online reviews—especially on independent platforms like Trustpilot—can reveal a lot about a company's reliability and customer service.

Look for consistent praise across multiple areas: build quality, finish, aftercare and professionalism. One glowing review is nice—but a pattern of satisfied customers is what really matters.

Cosy tip: Trust the feedback from people who’ve already been through the process, it’s one of the best tools you have.

7. Comparing Based on Price Alone

Two garden rooms may appear similar at first glance—but look closer and you might find one includes groundwork, heating, flooring, and lighting, while another charges extra for the basics. What looks like a bargain may not be once you factor in all the extras.

Another common mistake is comparing based on external dimensions alone. One quote might include premium cladding, superior insulation, or a more durable base—making it a better investment overall.

Cosy tip: Always ask for a full breakdown of what’s included and make sure you’re comparing like-for-like.

Final Thoughts

A garden room is a big investment and a wonderful opportunity to enhance your home and lifestyle. Avoiding these common mistakes helps ensure you end up with a space that’s not only beautiful but genuinely works for you all year round.

If you have questions or want to talk through your ideas, we’re here to help.

If you would like any advice please call us on 0115 77 22 715 Email mark@cosygardenrooms.co.uk