There are several different options available for a log cabin base including concrete. The choice will depend on budget, size and the time available for installation.
Once the decision has been made to purchase a log cabin the planning stage can begin. Before the garden building can be constructed, a base needs to be installed that the log cabin will be placed on.
A high-quality base is just as important as the cabin itself and everything you install after will depend on the integrity of the base underneath. While it can be tempting to skip a new base such as by using an old patio, problems can arise when construction of the log cabin begins. Even the smallest of garden buildings can weigh hundreds of kilograms and that’s before furniture and people are inside.
Getting the base correct is important and there are plenty of examples online where construction has been halted due to the base not being suitable. Common issues include the size being too small or existing groundwork not being level.
Does a log cabin need a concrete base?
While a concrete base is not 100% required, we strongly recommend using a concrete base when possible. Without a doubt, the best solution to meet all of the requirements of a log cabin base is to use concrete.
For any garden building, especially a log cabin, the base must be completely level and solid. When a cabin is built in the factory it uses precision equipment and is manufactured to very tight tolerances. This allows the logs to create a tight and waterproof seal. During construction, each piece is slotted together in layers until the roof is reached. A slightly uneven base can lead to interlocking logs not fitting together correctly.
The result of an uneven base is often disastrous for a log cabin and within a few years, the building can show signs of wear. Gaps appearing in walls can lead to moisture getting inside the cabin, resulting in damp during the colder months. The timber can also become strained and may end up warped, leading to windows and doors becoming difficult to open and not operating smoothly.
A concrete base is the easiest solution to create a consistent level base underneath a log cabin as it can be professionally levelled during construction. The base must also be solid to prevent movement over time. Concrete provides the strength and rigidity to keep the building in position and ensure no movement even with a full log cabin.
How is a concrete base installed?
Installing a concrete base is easier than many expect and can be completed as a DIY job where budget is a concern. Once a suitable location has been found, part of the existing ground will need to be dug up. A concrete base cannot be placed on top of grass or mud and a sub-base needs to be installed first.
Exact measurements will depend on the size of the log cabin, but an 8cm sub-base of type-1 hardcore is common. The hardcore is compacted into the ground and then covered over with ballast. 8cm of concrete can then be laid on top to form the concrete base, which will be raised slightly above the surrounding ground.
The base is marked out using wooden shuttering to form a wall around the exterior. Concrete is poured inside until it reaches the top and fills the base. A spirit level is used to ensure the base is level and a tampering board will level off and smooth over the surface.
For larger concrete bases, a damp proof membrane (DPM) is used to prevent the flooring underneath the log cabin from becoming damp. The DPM is installed a few centimetres above the surrounding ground to prevent any damp rising through the base and forming on the building.
Concrete bases take a long time to dry out and should be installed in advance of the log cabin construction. Three weeks is common to ensure the base is completely dry and solid.
Alternative log cabin base options
Sometimes, installing a concrete base is not always possible. Pouring a lot of concrete can be a challenge if access is limited and installing a log cabin on a budget may require a different solution.
Ground screws
Ground screw solutions have been changing the way garden buildings have been installed over the last few years. The idea allows for a building to be installed without the need for the usual base, allowing for installation on areas such as grass and gravel.
A ground screw looks like a very large screw that is placed into the ground. A number of these will be placed around the outside of the base to evenly support the weight of the garden building. For a sloping garden where a concrete base would be difficult or expensive, ground screws are ideal as each can be installed at a different depth to get a consistent height.
Typically, the ground screws will be installed at the same time as a log cabin as they can be immediately weighted and there’s nothing to dry out. The ground screws can also be raised to allow airflow underneath the log cabin that will protect against dampness and puddling water during the winter.
As a lot of log cabins don’t come with suitable flooring, a timber frame will need to be created that will attach to the brackets on the ground screws. The log cabin manufacturer may be able to build this or a separate installation in advance may be required.
Patio paving slabs
Using paving slabs is common for garden buildings such as log cabins. Many of us will already have an area in the garden with paving slabs installed that can be repurposed as a log cabin base. Be careful using an existing patio as it may not be completely level so that rainwater can run off. for a log cabin, the patio must be level. Smooth flat paving slabs are also required, any with patterns in will not be suitable.
One of the benefits of using paving slabs is that they are cheaper to use than a concrete cabin base. There is also less drying time required before the cabin can be placed on top. The gaps between paving slabs can be designed for rainwater to run between and prevent a build-up below the log cabin.
If an existing patio is being used, construction will be focused on ensuring the paving slabs are level and solid enough to take the weight of the building without movement. For a new paving slab base, the construction process is similar to a concrete base. A sub-base using hardcore will be installed and the paving slabs will sit on top. Slabs are placed into position one at a time and checked to ensure they are all level.
Guide: Choosing a log cabin base
Tips for a successful log cabin base
A successful log cabin base needs to be planned in advance for best results. Let’s take a look at some of our favourite tips for ensuring a log cabin base is successful.
Plan early – Installing a log cabin base is time consuming and a suitable base needs to be in position in advance of the log cabin installation date. If construction is taking place during the winter, a concrete base will need longer to dry before it is suitable for placing the cabin on. If the base is being completed as a DIY job it may take several weekends to get it finished.
Dimensions – The dimensions of a base are measured using the external measurements of the log cabin. Ideally, the base should be a few centimetres larger than the log cabin on every side. This allows for any movement or slight inaccuracies in the building or base size. Making the base too large will allow water to puddle at the edge of the cabin, whereas just a few centimetres on the edges will still allow rainwater to run off.
Maintenance space – The construction of a log cabin often requires access all of the way around for tasks such as painting and getting the interlocking logs into position. A log cabin base should be positioned to allow a person access to every side. Enough space allows for ongoing maintenance such as reapplying paint after several years. The gap around each side also provides plenty of ventilation to stop moisture and damp issues.
Sunny location – The positioning of a log cabin can affect how warm it feels throughout the year, particularly in the colder months. We favour placing the base in a position that gets lots of sunlight and will allow the light to come through the log cabin windows. It’s best to avoid the cabin being placed underneath a tree as it can block light and cause debris to fall on top that could cause damage.
Guide: Bathrooms in a garden room
Verdict
Overall, a concrete base is the best option for a log cabin. Any garden building is reliant on the base to create a solid foundation for the construction to be completed on top of. The log cabin base needs to be 100% level and solid to support the weight of the cabin.
Installation is similar to creating a shed base and can be completed by a local tradesman or as a job during the weekend. Where a concrete base is not possible, such as on a slope, other options are available including ground screws.
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