Are you worried about your garden room’s stability?
So many of our hybrid customers are excited to receive delivery of their garden room but are unsure of what base they need to ensure their new building is safe and stable.
There are a few things you need to consider when deciding on your garden room base, such as the size and weight of your building and the ground conditions of your garden.
A building’s foundation is one of the most important aspects to consider because it needs to be able to withstand the weight of the entire structure. The base should always be the same size as the footprint of the building.
The base that is “considered the best” and can accommodate most garden rooms is a concrete slab base. It is considered to be the most universal of all foundations. A concrete slab is a single layer of concrete, usually 4 inches (10 cm) thick, that is poured on top of the compacted ground.
A big advantage of having a concrete slab base for your garden room is that it can be easily extended if you ever want to increase the size of your building.
In this article, we will explore the most popular types of base used for garden rooms and highlight the most popular choice among our customers.
Why is the Type Foundation So Important?
The foundation is the most important part of any building. It provides a flat, level, and stable surface to build on. It is also essential in ensuring that your garden room remains weatherproof and secure.
Foundations can either use post tension cables or reinforced with steel rods (rebar). The slab is strengthened by the extra steel and concrete, making it sturdy enough to support a Garden Room or other building.
The concrete slab is usually positioned on a layer of sand to improve drainage conditions and act as a cushion.
There is no crawl space or basement under a slab foundation so, ideally, any wiring or plumbing must be installed before the concrete is poured.
You have probably driven past building sites and seen bits of pipe and wires sticking up through the poured concrete.
This is down to the fact that it’s much easier to install the services before the concrete is poured.
The Type of Foundation Used Is Determined by Your Site
As you can imagine, there are several variables that will affect the type of foundation you can have for your garden room. The first, and most important factor is the location and ground conditions of your garden.
If you have good, firm soil then you have a few more options available to you than someone who has softer soil that is prone to movement. The condition of the ground will also affect how easy it is to excavate and prepare the site for your new building.
It’s also worth noting that if you live in an area that is prone to flooding then you will need to take this into account when choosing your foundation.
Raised foundations are a good option in these circumstances as they provide additional protection against flood waters.
The Size and Weight of Your Garden Room
Another important factor to consider is the size and weight of your garden room. Larger buildings and those made from heavier materials will require a more substantial foundation than a smaller garden room.
You also need to think about how you want to use your garden room. If you plan on using it as a home office or gym then you will need to consider the extra weight of any equipment you plan on putting inside.
The Design of Your Garden Room
Finally, you need to think about the design of your garden room. If you have a bespoke design then we will be able to advise you on the best type of foundation for your project.
What Types of Bases Are Available?
There are many different types of foundations available, from a simple decking base to a more substantial concrete slab.
The most popular bases for garden rooms are:
- Concrete Slab.
- Ground Screws.
- Concrete Pile.
- Timber Decking.
The concrete slab is the most popular type of foundation among our customers. It is quick and easy to install and provides a very strong and stable base for your garden room.
It is also the least expensive option to construct. Since wooden floor joists aren’t needed, the total cost of materials is lower.
Also, since there is no crawl space, there’s no need to add air conditioning or heating, which saves on the overall price.
One drawback of a concrete slab is that it can be difficult to make changes or additions after the garden room is built. This is because the building will need to be dismantled in order to make any alterations.
A concrete base is best for garden rooms that are:
- Located on soft or firm ground.
- Not too large or heavy.
- Not subject to flooding.
A plinth is a raised foundation that is usually made from concrete. It is a good option if your garden room will be located on soft ground or in an area that is prone to flooding. Although it’s not as popular as a concrete slab, it can be a good choice for certain projects.
One advantage of a plinth is that it provides easier access to the underside of your garden room. This can be useful if you need to make any repairs or additions in the future.
Another advantage is that it raises your garden room up off the ground, which can help to protect it from flooding.
However, one disadvantage of a plinth is that it can be more expensive to construct than a concrete slab. This is because it requires more materials and labour to build.
A plinth is best for garden rooms that are:
- Located on soft or uneven ground.
- Prone to flooding.
Ground screws are a type of foundation which is becoming increasingly popular for garden rooms.
Just like 100mm screws, but one hundred times larger, they are driven into the ground using a specialist machine. Once in place, they provide a very strong and stable base for your garden room.
They are quick and easy to install and can be removed if necessary. This makes them a good choice if you plan on moving your garden room in the future.
One disadvantage of ground screws is that they can be difficult to install in certain types of soil, such as clay.
Another drawback is that they provide less protection against flooding than a raised foundation.
Ground screws are best for garden rooms that are:
- Not too large or heavy.
- Located on firm ground.
A concrete pile is a type of foundation which is often used for large or heavy garden rooms. It consists of concrete pillars which are driven into the ground using a specialist machine.
Once in place, they provide a very strong and stable base for your garden room. However, they are more expensive to install than other types of foundations.
For that reason, it’s not usually a popular choice among our customers.
Concrete piles are best for garden rooms that are:
- Large or heavy.
- Located on firm ground.
Timber decking is a popular choice for garden rooms that are located on uneven or sloping ground. It is quick and easy to install and provides a stable base for your garden room.
You would normally build a frame out of timber joists and then cover it with decking boards. This can be done by a handyman or a carpenter.
One disadvantage of timber decking is that it is not as strong or stable as other types of foundation.
It is also more susceptible to weather damage and rot, so it will need to be regularly maintained.
Timber decking is best for garden rooms that are:
- Not too large or heavy.
- Located on uneven or sloping ground.
- There are a few different types of foundations that can be used for garden rooms, including concrete slabs, plinths, ground screws, and timber decking.
- There are several factors to consider when choosing the best foundation for your garden room, such as the size and weight of the building, ground conditions, and susceptibility to flooding.
- The most universal foundation choice is a concrete slab. Not only is it the cheapest option, but it is also the quickest and easiest to install.
Do you need to dig foundations for a garden room?
The short answer is yes, you will need to dig foundations for your garden room. The depth of the foundations will depend on the type of foundation you are using.
Does an insulated concrete slab cost more than a regular concrete slab?
Insulated concrete slab costs vary based on the thickness of insulation and type of concrete. However, in general, an insulated concrete slab will be more expensive than a regular concrete slab.
Does a concrete slab need damp proofing?
A damp-proof membrane is required if the concrete slab is being laid on damp ground. This will prevent moisture from rising up into the slab and causing problems such as mould or mildew. A Polyethylene 1200 Gauge DPM is the most common type of damp proof membrane.
Can you get a garden room base kit?
Yes, you can buy garden room base kits which include everything you need to create a concrete slab foundation. These kits usually come with a DPC (damp proof course) and reinforcement mesh. You will also need to purchase concrete and hire a mixer. Alternatively, you can have the kit delivered and installed by a professional.
What is the best way to insulate a garden room?
There are several ways to insulate a garden room, including using insulation boards, spray foam, or mineral wool. The best way to insulate your garden room will depend on the type of construction and the climate in your area.
Main image: Oakwood Garden Rooms