How Big Can a Garden Room Be?

Garden rooms have surged in popularity as flexible living spaces. Think of it as your personal blank canvas — a communal space by the garden for family to gather in the evening or a peaceful home office or something entirely unique to your needs. With such adaptability, it is natural to wonder about the limits of these spaces and one question we get asked most often is this, “How big can a garden room be?” 

We can answer this question because we have been building Garden Rooms in St Albans. We have helped our clients maximise their garden space by blending creativity with a lot of know-how to tailor each garden room to fit not just their garden, but also their lifestyle! 

Let us dive into the details that help size up the perfect Garden Room for you, showing you how we turn your ideas into reality, one square foot at a time.

How Big Can a Garden Room Be? 

The size depends on three important factors: the purpose of the garden room, the size of your garden and your budget. 

These elements collectively influence the ultimate dimensions of your garden room, shaping it into a space that perfectly aligns with your aspirations and the practicalities of your property.

Purpose of the Garden Room

The intended use of your garden room plays a crucial role in determining its size. A cozy reading nook or a compact home office might only require a small footprint, whereas a fully-equipped home gym or a spacious art studio would naturally demand more square footage.

Garden Size

The physical dimensions of your garden are, understandably, a determining factor in the size of the garden room. A large garden offers more flexibility in terms of size and design, allowing for more ambitious projects. Conversely, a smaller garden will require a more thoughtful approach to maximise space without overwhelming the outdoor area. 


Your budget is another key consideration that can influence the size of your garden room. Larger, more elaborate structures will generally require a higher investment, both in terms of materials and construction efforts. 

However, a well-planned garden room, regardless of size, can add significant value to your property and your lifestyle. 

Is there a size limit for a garden room?

While detailed considerations on planning permission can be found on our blog it is worth noting that Garden Rooms often enjoy a degree of flexibility under permitted development rights. 

But for example, if your property is a listed building, or if the Garden Room covers more than 50% of the land around the original house, planning permission is necessary. Additionally, if the Garden Room has a raised platform or balcony, exceeds a certain height (more than one storey or 3 metres high), or is positioned at the front of your property, you will need to seek planning permission​​​​.

This means that there is no size limit as long as it fulfils the criteria we have mentioned above, subject to specific size and location criteria. 

And if your Garden Room is small, it can be built without the need for planning permission. However, for those desiring more substantial constructions, obtaining planning permission is required for a larger and more customised space.

Want to discuss your Garden Room in St Albans?

At PMG Garden Rooms, we pride ourselves on our ability to tailor Garden Rooms to your precise specifications, navigating the nuances of size regulations to maximise your space. Whether under permitted development rights or through planning permission, we ensure that your Garden Room not only meets legal requirements but also your personal vision and needs.

Our project portfolio showcases a diverse range of Garden Rooms, from snug retreats nestled in small gardens to expansive studios that make a statement. Each project illustrates our commitment to bespoke design and customer satisfaction, with the size of each Garden Room thoughtfully considered to enhance its surroundings and functionality.

Contact us today to begin planning your ideal Garden Room in the St Albans area and we will guide through the details like planning permission to construction.