10x8 Shed Bases

Which shed base kit fits a 10x8 shed?

Start with the shed, not the kit. One sold as 10ft x 8ft is rarely exactly that, so find the external size at the base in its listing and work in metres. Then choose a platform that's the same size or a little bigger.

Each ProBASE grid measures 500 x 500mm and is 40mm deep, so a finished base always grows in half-metre steps. Most 10ft x 8ft sheds sit on a platform 6 grids long and 5 wide. That's 3.0 x 2.5m and 30 grids.

The 9x9 kit holds 36 grids, which lays a full 3.0 x 3.0m square. Use 30 of them under the building. Then keep the last row of 6 as a dry step in front of the doors, or as a strip along the side for the wheelie bin. If yours is a little over 3m long, lay the grids 7 long and 5 wide instead (35 of them, 3.5 x 2.5m) and the same kit still covers it.

The grids lock together on all four sides, so the kit's name doesn't fix the shape. The maker shows other layouts on the ProBASE website.

10x8 shed bases compared

Here's how the ProBASE range lines up. Platform is the real size of the base laid as the kit intends. Gravel is the total at the 15kg per square Shedstore advises. Prices move daily (the grid above always shows today's price), so they're in bands here.

Every pack is the same grid system with a different number of pieces. Each box holds the same three things.

• Interlocking grids of recycled plastic, each 500 x 500 x 40mm. They're lightweight to carry through the house but strong and durable once filled.
• A heavy-duty weed membrane, commercial grade, to lay under the grid.
• A 2 year guarantee from the maker, plus full instructions that show you how to assemble the base.

Gravel isn't in the box, though. Shedstore recommends 10mm pea gravel, so book a bulk bag delivery from a builders' merchant for the week the kit arrives. Delivery of the kit itself is free to most mainland postcodes, although Shedstore lists a few Highland and island areas outside its delivery zone, so check your postcode before you order.

Our sheds this size and the base each one needs

These are real footprints at the base from the listings of the sheds this size we stock, with the grid layout that covers each one.

The Keter Stronghold is the classic 10ft x 8ft model and it sits neatly on 30 grids. The Rubicon is the one to watch. At 3.03m long it's a few centimetres over a 6-grid run, so give it 7 grids that way rather than let a corner hang off the edge. Both Palram models list their own anchor kits, so fix them down once the gravel is in. Browse more on our Keter Stronghold sheds and large plastic sheds pages.

12x8, 10x10 and 12x10 shed bases

The bigger kits cover the sizes just above this one.

• 12x8 shed base. A 12x8 shed is about 3.7 x 2.4m, so lay 8 grids by 5 (40 of them, 4.0 x 2.5m). The 48-grid 12x10 kit covers it with 8 spare.
• 10x10 shed base. Around 3.0 x 3.0m, which is exactly the 9x9 kit laid as a full square. If it's even slightly over 3m either way, step up to the 11x9 kit.
• 12x10 shed base. The 12x10 kit lays 4.0 x 3.0m, enough for most 12x10 sheds and small workshops.
• Smaller sheds. For 8x6, 8x7 and 7x5 models see our 8x6 shed bases. For the smallest stores try our 6x4 shed bases.

How to lay a plastic shed base

Two people can lay a grid base this size in a day. Most of that time goes on the ground. The grid itself is easy to install and simple to assemble, with no concrete to mix and no special tools.

1. Mark out an area a little bigger than the platform with pegs and string. For a 3.0 x 2.5m base, mark about 3.2 x 2.7m.
2. Strip the turf and any soft topsoil, then rake the soil flat.
3. Compact the ground firmly. On clay or soft soil, tamp down a thin layer of hardcore or sharp sand first so the grid can't settle.
4. Check it's level both ways with a spirit level on a long straight board.
5. Roll out the heavy-duty membrane and overlap any joins so weeds can't find a gap.
6. Clip the interlocking grids together on top, working out from one corner.
7. Fill every cell with gravel, brush it flat and check the level again.

Thirty grids take about 450kg of gravel, so one bulk bag usually does it with a little over. Spread what's left as a strip around the walls. That works as a simple french drain, so rain runs away from the base instead of splashing mud up the panels.

Shedstore doesn't lay these kits for you. If you've booked its team to build the shed, have the base finished and filled before they arrive.

ProBASE also makes anchor blocks that sit in the grid in place of gravel. You screw or bolt the timber frame of a garden building to each anchor block, which stops it shifting in high winds. Its french drain blocks run along the walls to stop rain splashing back onto the timber. Neither is in the kits here, so buy them from ProBASE if you want them.

Why a big plastic shed needs a level base

Plastic and resin sheds are fussier than timber ones. A big one is heavy too, once it's full of mowers and bikes. The wall panels slot into the floor. If the base dips at one corner, the frame twists, the doors stop meeting and panels can work loose. Even one with its own floor needs a flat surface under it, as our plastic sheds with floors page explains.

A gravel-filled grid keeps things dry too. Drainage is built in, as water runs straight through the open cells. The ventilation under the floor keeps damp out too. A building this size catches the wind, so fix it down with ground anchors from our shed security range.

Other ways to build a base for a large shed

A plastic grid isn't the only route. Here's how the usual options compare at this size.

• Concrete slab. The strongest and most permanent foundation. For 3.0 x 2.5m at 100mm thick you'd need about 0.75 cubic metres of concrete on compacted hardcore, plus formwork and several days to cure. It's a big job for storage and hard to remove later.
• Paving slabs. Twenty 600 x 600mm slabs laid 5 by 4 make 3.0 x 2.4m. Each one needs bedding and levelling. Just one rocking slab shows up in the floor.
• Wooden shed base. A pressure treated timber frame of bearers is quick to lay on gravel or slabs. Plenty of timber merchants sell a wooden shed base cut to 10ft x 8ft. Pressure treated wood lasts well, but on damp ground it can still rot in the end.
• Adjustable base. On a slope or an uneven old patio, steel brackets level a timber frame without digging. QuickJACK Kit 3 lists 10ft x 8ft among its sizes, in versions for hard and soft ground. You supply the pressure treated timber. See our adjustable shed bases.

So why pick a plastic grid over slabs or concrete? It's quick to install, with nothing to set. The grids push together by hand and are light to carry. They're made from recycled plastic that won't rot. Once filled they're strong enough for a full workshop. You can also lift the whole base and reuse it if you ever move. The same kits suit a log cabin, a summerhouse or any timber garden building just as well.

You'll also see similar grids from other brands on Amazon and at B&Q. Check the grid size, whether a heavy-duty membrane comes in the box and what guarantee you get before you compare prices. A strong summerhouse base needs the same care as one for a shed.

Do you need planning permission for a shed this size?

Usually not in England. A garden building is permitted development if it stays behind the front of the house, is single storey and covers no more than half the garden. Within 2m of a boundary it can be no taller than 2.5m. The Keter Stronghold's ridge sits at 2.51m, so leave a little gap from the fence or check before you build. The Planning Portal guide to outbuildings has the details. The government's permitted development technical guidance explains how height is measured from the ground.

A 40mm grid base adds very little to that height. Listed buildings, flats and conservation areas have extra rules. Wales, Scotland and Northern Ireland set their own.

10x8 shed base FAQs

How many grids does a shed this size need?

Thirty, laid 6 long and 5 wide for a 3.0 x 2.5m platform. If the shed measures a touch over 3m, lay 7 by 5 instead, which takes 35.

How much gravel will I need?

About 450kg of 10mm pea gravel for 30 grids, at 15kg each. Order a little more if you want a gravel strip around the shed.

Do I have to fill the grids with gravel?

Yes, for these kits. Shedstore's listing for every pack recommends gravel in each grid. It adds weight and strength and locks the grid in place.

Can I lay a shed base straight onto grass?

Not straight onto turf, no. Strip the grass and soft topsoil, compact the ground and check it's level, then lay the membrane and the grid.

Should the base be bigger than the shed?

At least as big as the shed's footprint at the base. A little bigger is better. A margin of gravel keeps soil and grass away from the walls.

Will a plastic grid hold a heavy shed?

Yes, once it's filled with gravel. The grid spreads the load across the whole platform, so it copes with a building full of tools, bikes and a mower. Keep the ground underneath firm and well compacted.

What guarantee do the kits have?

Each ProBASE kit has a 2 year guarantee. The recycled plastic won't rot, so a well-laid base should last far longer than that.