By the UK Glasshouse Guide — Expert Reviews, Comparisons & Buying Advice Team · Updated May 2026 · Independent, reader-supported

Best Glasshouse Flooring Options UK: Slabs, Gravel or Decking?

Choosing the right floor for your glasshouse is more than aesthetic—it affects drainage, plant health, maintenance effort and how long your structure will last. UK growers have three main options: paving slabs, gravel, and timber decking. Each has genuine strengths and real limitations depending on what you're growing and how you use the space.

Concrete and Paving Slabs

Concrete is the most common choice for UK glasshouses, and there's a reason. Laid properly over a compacted base or existing hardcore, concrete provides a stable, long-lasting surface that won't shift under the weight of benches or foot traffic through wet seasons.

Drainage is the critical detail here. Concrete doesn't drain—water pools on the surface. For a glasshouse where you're standing and working regularly, this means puddles become a slip hazard, especially in winter. More importantly, trapped moisture underneath concrete creates conditions for root diseases and algae growth on benches. The solution is laying a proper fall (typically 1 in 40 slope) to guide water towards one or two strategic drain points, or choosing porous concrete products that let water through.

Standard flagstones or utility slabs are inexpensive and sturdy, but they're genuinely slippery when wet. Anti-slip treatments help, though they degrade and need reapplying. For a glasshouse, textured or riven paving is worth the modest premium—it naturally grips better and weathers more attractively.

Hygiene is straightforward. Hard surfaces are easy to sweep, hose down and disinfect between growing seasons. If you're managing pests or soil-borne diseases, this is valuable. Concrete also doesn't harbourer pests underneath, unlike decking.

Cost is reasonable. Expect £25–40 per square metre for basic paving slabs laid DIY, or £40–60 if hiring labour. A 3m × 4m glasshouse works out to roughly £300–720 depending on slab quality and whether you're doing the groundwork yourself. The upfront cost is higher than gravel but concrete lasts 20+ years with no maintenance beyond the occasional sweep.

Gravel

Gravel is popular because it's cheap, fast to lay, and excellent for drainage. Water runs straight through it, which means you'll never have puddles or waterlogging—a real advantage in a wet UK winter.

The trade-off is hygiene and maintenance. Gravel mingles with soil over time. Weeds germinate through it. Seeds from plants spill onto it and take root. You'll spend time raking, weeding, and eventually replacing the gravel as it compacts and gets mixed into the soil beneath. For a serious grower managing clean stock, the constant contamination is a genuine problem.

Drainage is excellent, which makes gravel ideal if you're propagating cuttings or starting seeds—these don't tolerate waterlogging, and gravel naturally creates the free-draining base they need. It's also the cheapest option: bulk gravel costs £8–15 per tonne, so a 12 m² floor costs £30–50. Lay weed membrane underneath to slow (though not eliminate) the problem of gravel mixing with soil.

For cleanliness, gravel loses points. Small stones stick to wet boots. Dirt splashes onto benches and foliage. If you're also storing pots or tools, gravel picks up debris everywhere. Hosing down doesn't clean it properly. Spring cleaning means essentially sweeping out and replacing the top layer.

Longevity is moderate. Gravel settles and migrates, especially in a high-traffic glasshouse, so you'll top it up every few years. Over a decade, the labour and replacement costs add up, though the material cost stays low.

Gravel works best in a specialist propagation house or a space where you're mostly working with potted plants rather than floor-standing benches.

Timber Decking

Decking looks attractive and creates a modern, usable space—especially valuable if your glasshouse doubles as a lean-to garden room. It also provides good grip underfoot, even when wet, making it safer than smooth concrete or greasy gravel.

Drainage is fine, water runs between the boards (assuming deck boards are spaced properly), though moisture underneath can accumulate. Hardwoods like cumaru or ironbark weather better than softwoods and resist rot for 15–20 years. Pressure-treated softwood (the budget option) typically lasts 8–12 years before needing replacement or heavy maintenance.

The real limitations emerge with glasshouse conditions. Timber is exposed to constant moisture, heat and shade—a perfect environment for rot, mildew and wood-boring insects. Even durable hardwoods require annual cleaning and treatment to prevent staining and degradation. Every 5–7 years, your decking will need sealing or restaining to maintain appearance and protect against weather.

Cost is deceptive. A budget softwood deck costs £30–50 per square metre, but a durable hardwood deck runs £80–150. Accounting for the replacement cycle, labour for maintenance and treatment costs, decking is expensive over 20 years. It's the best choice aesthetically, but the worst for uninterrupted functionality.

For hygiene, decking is the weakest option. Spilt water and soil seep between boards, creating hidden spaces where pests live and diseases develop. You can't hose it down and disinfect it between seasons the way you can concrete. If disease management is part of your routine, decking makes that harder.

The Practical Choice

For most UK home growers, concrete with proper drainage is the sensible default: reliable, low-maintenance and genuinely cost-effective over time. If budget is tight and you're propagating, gravel with good weed membrane works. Save decking for a space where aesthetics matter more than intensive growing.