The Complete Guide to Shed Bases: Concrete, Gravel or Timber?

A proper shed base does three critical jobs: it provides a level surface for your shed to sit on, it lifts the timber off the ground to prevent moisture contact, and it distributes weight evenly to prevent sinking or tilting. Without a good base, even the best-built shed will deteriorate quickly. Damp rising through the floor is the single biggest cause of premature shed failure in Scotland's wet climate.

A concrete pad is the most robust and long-lasting base option. It consists of a poured concrete slab, typically 75–100mm thick, laid on a compacted sub-base of hardcore or MOT Type 1. Pros: Extremely durable, perfectly level, suitable for all shed sizes including heavy workshops. Provides excellent moisture protection when combined with a damp-proof membrane. Cons: More expensive than other options. Requires curing time (usually 48–72 hours). Permanent — harder to relocate. Best for: Large workshops, heavy-duty sheds, garden rooms and any building over 8×6 feet.

A gravel base uses compacted pea gravel or 20mm stone laid within a timber or plastic frame. It provides good drainage and is quicker and cheaper to install than concrete. Pros: Excellent drainage, cost-effective, can be installed in a few hours. Allows some future repositioning. Cons: Less suitable for very heavy buildings. Requires a weed membrane underneath. May settle slightly over time on clay soils. Best for: Standard garden sheds (6×4 to 8×6), bike sheds, and smaller storage buildings.

A timber frame base uses pressure-treated bearers laid on blocks or compacted ground. The shed floor sits on top of the bearers, creating an air gap underneath. Pros: Quick to install, cost-effective, good airflow prevents moisture build-up. Suitable for uneven ground when used with adjustable blocks. Cons: Bearers need to be pressure-treated or they'll rot. Not ideal for very large or heavy structures. Best for: Moderate-sized sheds on reasonably level ground, allotment sheds, and situations where you might relocate the shed later.

Edinburgh's varied terrain — from flat coastal areas in Portobello and Musselburgh to the hilly Pentland-foot gardens in Penicuik and Balerno — means there's no single 'best' base for everyone. For sloping sites, a stepped concrete base or adjustable timber frame is essential. For clay-heavy soils common in parts of West Lothian, concrete provides the most stable foundation. For well-drained sandy soils near the coast, gravel bases work excellently. During your free site survey, we assess ground conditions, slope, drainage and soil type to recommend the best base for your specific garden.

Yes — if you have an existing flat, level concrete patio or slab, it may be suitable as a shed base. We'll check the level and condition during your site survey. Minor imperfections can often be corrected with shims. Avoid placing a shed directly on soil, grass or decking. These surfaces trap moisture against the timber floor and dramatically shorten the shed's lifespan.