Shed flooring decisions affect both upfront costs and long-term functionality. The three main options—concrete slab, timber deck, and compacted gravel base—each work well for specific uses but poorly for others. Understanding the trade-offs helps match flooring to your actual needs rather than defaulting to whatever seems standard.

Concrete Slab

Concrete slabs provide the most durable, permanent shed foundation. They support heavy equipment, resist moisture, and last decades with minimal maintenance.

For workshop sheds housing machinery, concrete makes sense. The flat, level surface supports drill presses, table saws, and other stationary equipment. It won’t sag under heavy loads or deteriorate from oil spills and other shop chemicals.

Storage sheds for vehicles or heavy equipment also benefit from concrete. A riding mower, motorcycle, or trailer won’t damage concrete floors the way they might crack or compress other materials.

But concrete is expensive. Typical costs run $100-150 per square meter for basic slabs including excavation, base preparation, reinforcing mesh, and finishing. A 4m × 6m shed (24 sqm) means $2,400-3,600 just for the floor before any shed structure.

Site preparation adds cost too. Sloping blocks need more excavation and fill to create level pads. Poor soil conditions might require deeper excavation and better base preparation. Accessible sites cost less than backyards requiring concrete pumping.

Concrete takes time. You need to excavate, prepare base, form, pour, and cure before building the shed. This adds weeks to project timelines compared to other flooring options.

Cold climates create additional considerations. Concrete slabs without insulation create cold floors that make heated workshops less efficient. Adding insulation under slabs increases costs but improves comfort.

Timber Deck

Timber decking for shed floors costs less than concrete while providing solid, level surfaces. Typical costs run $60-100 per square meter for treated pine bearers, joists, and decking.

Construction is faster than concrete. Excavate for stumps or piers, set bearers, install joists, lay decking. You can build the shed structure immediately without waiting for concrete to cure.

Timber suits storage sheds for garden equipment, outdoor furniture, and general storage. It keeps items off ground level, preventing moisture damage. Airflow under timber decks reduces humidity and condensation.

Workshops can work on timber floors but with limitations. Heavy stationary equipment might cause sagging or bouncing. Dropped tools can dent or crack timber more easily than concrete. But for light workshop use—hand tools, workbenches, portable power tools—timber is adequate.

Timber durability depends on wood treatment, ventilation, and maintenance. H3 treated pine resists decay and termites reasonably well. Adequate ventilation under the deck prevents moisture accumulation that accelerates rot.

Maintenance requirements are higher than concrete. Decking eventually needs replacing—10-20 years depending on conditions and treatment level. Inspection for rot and termite damage should happen periodically.

Weight capacity is lower than concrete. Concentrated heavy loads can cause localized sagging. For distributed loads like boxes, tools, and equipment stored on shelves, timber handles this fine.

Leveling is easier to adjust with timber than concrete. If the deck settles unevenly, you can add packing under bearers or joists. Concrete requires grinding or shimming equipment rather than adjusting the floor itself.

Compacted Gravel Base

Compacted crusher dust or gravel provides the cheapest shed floor option, typically $15-30 per square meter including excavation and compaction.

This works for basic storage sheds where moisture isn’t critical—firewood storage, garden tool sheds, potting sheds. Items sit on the gravel base or on pallets/pavers to keep them elevated.

Installation is quick. Excavate slightly, add base material, compact well. Build the shed directly on the base. No waiting for curing or complex construction.

But limitations are significant. Gravel bases stay somewhat uneven even when compacted. Setting up workbenches or stationary equipment is difficult on uneven surfaces.

Moisture from ground rises through gravel. Stored items sitting directly on gravel can develop mold or moisture damage. Pallets or pavers under storage help but don’t eliminate this entirely.

Weed growth happens unless you use landscape fabric under gravel and maintain periodically. Grass and weeds emerging through gravel floors look poor and are annoying to manage.

For some uses, gravel bases work fine. Firewood storage doesn’t require level floors or moisture protection. Garden equipment that’s already dirty tolerates gravel floors easily.

Upgrading later is possible. You can pour concrete over compacted gravel or build timber decking above it if needs change. This means starting with gravel doesn’t lock you into it permanently.

Combination Approaches

Some sheds use different flooring in different areas. Concrete in workshop sections, timber or gravel in storage sections. This matches floor type to use while controlling costs.

A shed with one end for workshop and another for garden storage might have concrete under the workshop area and gravel under storage. This costs more than all-gravel but less than all-concrete while providing appropriate surfaces for different uses.

Site-Specific Considerations

Slope affects flooring choice. Concrete requires cutting and filling to create level pads on slopes. Timber decking handles slopes more easily—varying bearer heights creates level decks without major earthworks.

Drainage matters for all options. Sheds in low areas with poor drainage need better foundation preparation regardless of flooring type. Concrete might crack from ground movement in poorly drained soils. Timber rots faster in constantly wet conditions. Even gravel becomes muddy mess without adequate drainage.

Soil type influences costs and performance. Sandy, well-draining soils need less preparation. Heavy clay requires better drainage and foundation work. Reactive soils might need engineered solutions beyond simple shed flooring.

Long-Term Costs

Initial construction costs differ substantially—concrete is most expensive, gravel cheapest. But maintenance and replacement costs over 20-30 years change the calculation.

Concrete needs minimal maintenance and lasts indefinitely. Initial higher cost spreads over decades of use.

Timber requires periodic maintenance and eventual replacement. Initial savings get partially offset by replacement costs after 15-20 years.

Gravel needs ongoing weed control and occasional topping up as material compacts. It’s cheap initially but requires more attention long-term.

For sheds expected to remain in place long-term, concrete’s durability justifies higher initial cost. For temporary structures or uncertain future needs, cheaper options make sense.

Matching Floors to Use

Garden storage sheds—gravel or basic timber deck works fine. These don’t need level surfaces or heavy-duty floors.

Workshop sheds—concrete for serious workshops with stationary equipment, timber for lighter workshop use.

Vehicle storage—concrete for cars, motorcycles, trailers. Possibly timber for lightweight vehicles like bicycles.

Hobby/craft sheds—timber usually adequate, concrete if heavy equipment involved.

General storage—depends on what’s being stored. Moisture-sensitive items need raised floors (timber or concrete). Bulk items tolerate gravel.

Making flooring decisions based on actual intended use rather than generic “shed floor” thinking prevents paying for unnecessary features or ending up with floors that don’t meet actual needs. Concrete where you genuinely need durability and heavy load support. Gravel where you need cheap, functional base. Timber as middle ground for many applications. Each has appropriate uses; none is universally best.