When planning to build a new shed, one of the most important decisions you'll make is what to put underneath it. Two of the most popular options in the UK are plastic interlocking shed bases and traditional concrete slabs. Both have their merits, but depending on your situation, one will likely be a far better fit.
In this guide, we compare plastic shed bases and concrete slabs across cost, installation difficulty, drainage, longevity, and environmental impact — so you can make the right choice.
What Is a Plastic Shed Base?
A plastic shed base is a grid of interlocking recycled plastic panels that sit on compacted ground or a layer of sand. The panels interlock to form a rigid, load-bearing platform. They allow water to drain freely through the base, keeping the underside of your shed dry. Our Premium Plastic Shed Base Kit supports shed sizes from 6x4 up to 20x10ft and beyond.
What Is a Concrete Slab Base?
A concrete shed base involves excavating the ground, laying a sub-base of hardcore, and pouring a concrete slab, typically 100mm thick. Once set, it forms a permanent, solid surface. It's been the traditional choice for decades — but it comes with significant drawbacks.
Cost Comparison
Plastic shed base: A plastic base kit for a standard 8x6 shed costs approximately £80–£150 including the grids and membrane. No professional labour is required. Total cost: £80–£200.
Concrete slab: Materials (concrete, hardcore, shuttering, mixing) for the same 8x6 shed typically cost £150–£300. If you hire a tradesperson to lay it, add another £200–£400 in labour. Total cost: £350–£700+.
Winner: Plastic shed base — significantly cheaper, especially when you factor in labour.
Installation Difficulty
Plastic shed base: Can be installed in 1–3 hours with basic tools. Level the ground, lay a weed membrane, interlock the panels, and you're done. No mixing, no waiting to cure, no heavy machinery needed.
Concrete slab: Requires excavation, a hardcore sub-base, timber shuttering, concrete mixing or ordering a ready-mix truck, screeding flat, and 24–48 hours curing time before use. A physically demanding job for most homeowners.
Winner: Plastic shed base — dramatically easier and faster to install.
Drainage
Plastic shed base: Permeable design allows water to pass through freely, preventing waterlogging under your shed. This reduces condensation, protects the shed floor from rot, and is kinder to the surrounding garden.
Concrete slab: Impermeable surface means water pools on top or runs off to the sides. Without proper drainage channels, this can cause damp problems under your shed over time. Concrete also contributes to surface water run-off, which can cause issues in gardens.
Winner: Plastic shed base — superior drainage in all conditions.
Longevity and Durability
Plastic shed base: High-quality recycled plastic grids are UV-stabilised and rated for 25+ years. They don't crack, rot, or degrade. Our shed base grids are rated to 25 tonnes load capacity, more than enough for any residential shed or workshop.
Concrete slab: Concrete can last decades but is prone to cracking over time, especially with freeze-thaw cycles in UK winters. Once cracked, it's expensive to repair and nearly impossible to remove cleanly.
Winner: Tie — both are long-lasting, but plastic is easier to repair or expand.
Environmental Impact
Plastic shed base: Made from recycled materials. Permeable surface is better for local drainage and ecosystems. Can be removed, reused, or recycled at end of life.
Concrete slab: Cement production is carbon-intensive. The slab is permanent — it can't easily be removed or repurposed, and may require a skip when demolished.
Winner: Plastic shed base — a more sustainable, eco-friendly choice.
When Is a Concrete Slab Better?
Concrete does have advantages in specific situations. If you're building a very heavy workshop, housing industrial machinery, or constructing a permanent structure like a garage or home extension, concrete's rigidity and thermal mass may be preferable. It also provides a completely flat, hard surface ideal for workshop use with heavy equipment.
For standard garden sheds, workshops, log cabins, and playhouses — plastic wins on almost every metric.
The Verdict
For the vast majority of UK homeowners, a plastic shed base is the better option. It's cheaper, faster to install, better for drainage, more eco-friendly, and just as durable. The only reason to choose concrete is for very heavy-duty permanent structures.
Ready to build your shed base? Browse our Premium Plastic Shed Base Kits — available for all standard shed sizes, with free UK delivery on orders over £200.