What Foundations Do Wooden Garages Need?

When planning wooden garages, the most important element is actually the foundation. A strong, level base keeps the structure stable, prevents movement, and ensures the installation goes smoothly. Without the right base, even the best-built garage will struggle to perform as it should. Let’s explore the options you have for foundations and what makes them suitable.

Types of Foundations for Wooden Garages

Different garages and sites call for different base solutions. The most common and reliable foundation types for wooden garages are:

1. Concrete Slab Foundations

A concrete slab is the most popular and durable option for a wooden garage. It provides a completely level, solid surface that can support heavy vehicles and equipment, making it ideal for classic car owners, hobby mechanics, or anyone looking for a long-term structure.

A typical concrete slab foundation will be around 100–150mm thick, poured over a compacted hardcore base and finished with a damp-proof membrane. Once cured, it creates a robust and smooth surface for installation. It’s a low-maintenance and high-performance choice, and the one we recommend for most permanent garages.

2. Concrete Perimeter or Ring Beam Foundations

For certain sites, a full slab isn’t essential. A concrete perimeter (or ring beam) foundation involves laying a reinforced concrete border around the building’s footprint. The central section can then be filled with compacted hardcore or left ventilated.

This approach offers several advantages: it uses less concrete, helps with drainage, and raises the structure slightly off the ground to reduce moisture exposure. It’s especially useful on uneven or sloped sites, or when airflow beneath the building is preferred.

3. Paving Slabs

For smaller garages or where access for heavy concrete work is limited, paving slabs can offer a practical solution. This involves laying thick concrete or stone slabs on a firm sub-base. It’s quick to install and can be a cost-effective alternative for lighter buildings. However, the slabs must be perfectly level and properly supported; otherwise, the structure could shift over time.

4. Ground Screws

These are large steel anchors screwed directly into the soil. They’re fast to install and minimise disruption to the surrounding ground. They’re often chosen for temporary or semi-permanent buildings.

The Role of a Good Foundation

Large single garage without planning permission

A good foundation supports and evenly distributes the building’s weight across the ground. It also prevents damp from rising into the timber and keeps the garage level for years to come. A solid base also helps doors open and close properly, avoids structural stress, and protects against future subsidence or water pooling.

Ground Preparation and Installation Tips

Before construction, clear the site of vegetation and debris, and excavate to firm, stable ground. A layer of MOT Type 1 hardcore, compacted thoroughly, will form a strong sub-base.

Always allow for drainage around the garage, either by slightly sloping the ground away from the structure or by installing a gravel channel to prevent standing water. It’s also important to include a damp-proof membrane (DPM) to stop moisture from rising through the floor.

Mistakes to Avoid

Even small errors in groundwork can cause long-term issues. Some of the most common mistakes include:

  • Building directly onto grass or soil, which can shift and lead to uneven floors.
  • Skipping the damp-proof membrane, which allows moisture to seep into the timber.
  • Poor levelling, which can cause doors to misalign and joints to strain.
  • Insufficient compaction, leading to settlement over time.

Choosing the Right Foundation

The best foundation depends on the size, purpose, and location of your wooden garage. A concrete slab offers unbeatable stability for heavy use, while a ring beam or paving slab base can be more suitable for lighter, smaller structures or trickier sites.

If you’re unsure, our team is happy to help. We’ll advise you on the ideal base for your chosen design and ensure your site is ready for installation, so your new garage stands strong for years to come.

Build on a Solid Foundation

Every Warwick Buildings garage begins with a reliable base. Speak to our team today for expert guidance on groundwork and foundation options, or use our online configurator to design and price your perfect timber garage.