What do you need before you can build a garden room? 

A garden?

Well yes, that helps!

But you also need a sturdy foundation.

The right foundation provides structural stability to your garden room, and determines the long-term durability of your new space. Stick with us while we explain the various foundation options to consider.

What are the best types of foundations for garden rooms?

1. Concrete Slab:

A concrete slab foundation is a popular choice for garden rooms. It involves pouring a solid concrete base that evenly distributes the weight of the structure. 

This method offers excellent stability and prevents moisture from seeping into the room, for a solid and long-lasting foundation.

However, a concrete slab foundation requires a lot of materials and is labour-intensive, so it is more expensive than other options. It can also take 1-2 weeks for the new foundation to set, which increases garden room build times. The use of concrete as a building material is also more damaging to the environment than other options.

2. Concrete Piers:

Ideal for areas with challenging soil conditions, concrete piers involve placing concrete pillars at strategic points to support the weight of the garden room. 

This method accommodates uneven terrain and provides a sturdy base by penetrating through unstable soil layers.

Unlike a concrete slab, you don’t have to dig up your garden to lay concrete, as the weight of the garden room structure will be evenly dispersed over an extensive area. 

Not only is this option more environmentally friendly than concrete, but it’s faster too. Concrete piers do not need time to set, and they provide durable protection against movement and pressure. This ensures your garden room is secure and stable, and protected from cracking.

Concrete piers are ideal if your garden is relatively flat and the soil is compact. They’re also more affordable than some other options, so they can be a good choice for those on a budget.

That said, concrete piers may not be the best choice if your garden is especially uneven, or the ground is boggy or soft.

If your garden is relatively flat and soil compact, we offer concrete pads as an effective, budget-friendly garden room foundation solution. To find out if this is the right choice for you, chat with our team to learn more.

3. Screw Piles or Helical Piers:

For eco-conscious individuals or those seeking a less invasive foundation option, screw piles or helical piers are a sustainable choice and becoming increasingly popular. These steel piles are screwed into the ground, offering a secure foundation without the need for extensive excavation. They’re versatile, minimising disruption to the surrounding landscape. You can safely create a level platform even when faced with sloping terrain.

However, before installing any ground screws, extensive and multiple site surveys are necessary in order to get a thorough understanding of the ground conditions, as loose or rocky soil can cause complications. If you have recently dug up the area, it’s advised to wait two years for it to settle. 

Installing ground screws usually involves the use of a ground drill. You may also need to undertake some garden landscaping, in order to hide the screws, which can prove costly.

4. Wooden Frame Base:

A wooden frame base, often known as a timber substructure, involves constructing a sturdy frame using pressure-treated timber. This base elevates the garden room off the ground, preventing direct contact with moisture. 

It’s suitable for level ground and can be a cost-effective solution to garden room foundations. 

Wood is also a popular choice for those who want a more aesthetically pleasing design, and an eco-friendly solution. 

Timber bases usually consist of ridge decking bases, which are great for preventing dampness from developing in your garden room. They do so by providing space for water to drain off the top, while space under the decking lets air circulate freely. 

One of timber’s major benefits is that it’s easy to install, taking less time than concrete bases. However, it will need more maintenance than other types of foundations, and while it is strong and durable, it’s not as heavy-duty as concrete or metal. This means it is suited to smaller projects.

5. Plinth Foundations:

Plinth foundations are typically made from reinforced concrete, and help distribute the weight of the garden room across a larger surface. 

One of the main advantages of this type of foundation is that they are fairly simple to install, and unlike concrete slabs, they do not require any setting time. They are particularly effective at withstanding high amounts of pressure and movement, preventing structural damage to your garden room.

This type of foundation is great for smaller garden room projects only.

Factors to Consider:

Soil Type: Assess the soil composition to determine the most suitable foundation type.

Local Regulations: Check local building codes and regulations regarding foundation requirements. You can read more about garden room planning permission here.

Garden Room Size and Weight: Consider the size and weight of your garden room to choose an appropriate foundation that can support it adequately.

What foundation do Urban Escapes garden rooms use?

At Urban Escapes we use unique heavy-duty composite posts which are concreted into the ground, with a stainless steel frame bolted on, which lifts the studio off the ground. This leaves a breathable space, removing the risk of rising damp and condensation. Depending on the size of your garden room, there will be 9-30 posts. Foundations are included in our standard garden room costs and can be laid on uneven sites; ideal for gardens with a slope.

Garden Room Foundations – In Brief

The foundation of your garden room lays the groundwork for its longevity and structural integrity. Assess your landscape, consider the local conditions, and consult with professionals to determine the most suitable foundation type. With the right foundation, your garden room will stand strong for years to come, providing an inviting and functional space in your outdoor haven.

The traditional way to prepare the foundation for a building is using concrete, but, thanks to improvements in technology, new ways are now available: Ground Screw, Screw Pile, Pads and concrete.