How to Choose the Right Farm Shed Size for Your Property

Choosing the wrong size farm shed is one of the most common and costly mistakes rural property owners make. Go too small and you’re cramped within a season. Go too large without planning and you’ve spent more than you needed to upfront.

Getting the size right from the start means your shed works harder for longer — and that starts with understanding exactly what you need it to do.

This guide walks you through the key factors to consider when sizing a farm shed for your South West WA property, so you can make a confident, well-informed decision before you build.

Why Farm Shed Size Is One of the Most Important Decisions You’ll Make

A farm shed isn’t a small purchase. It’s a long-term infrastructure investment that directly affects how efficiently your property operates day to day.

A shed that’s too small limits what you can store, forces you to leave equipment exposed, and often leads to costly additions down the track. A shed that’s properly sized — and designed with future growth in mind — becomes one of the most valuable assets on your property.

Getting the sizing right at the planning stage is far cheaper than modifying or extending a shed after it’s been built.

What Will You Actually Use the Shed For?

Before you think about dimensions, get clear on the primary purpose of your shed. The use case drives everything else.

Common farm shed uses include:

• Machinery storage — tractors, harvesters, headers, and implements
• Hay storage — baled hay stacked in rows or columns
• Grain storage — bulk grain or bagged product
• Fertiliser storage — including chemical compliance requirements
• Livestock shelter — shade and wind protection for cattle, sheep, or horses
• Workshop space — repairs, welding, maintenance
• Multi-purpose storage — a combination of the above

Many South West WA properties need a shed that serves more than one function. If that’s the case, plan each use zone separately, then combine them into a single structure. This is almost always more cost-effective than building multiple smaller sheds.

Not sure what size shed you need? Below is quick reference guide

How to Size a Farm Shed for Machinery Storage

Machinery sheds are the most common source of sizing errors. Equipment dimensions are often underestimated, and clearance requirements are overlooked entirely.

What measurements do you need before sizing a machinery shed?

Measure every piece of equipment you plan to store — not just the tractor. Include:

• Length and width of each machine
• Height at the highest point (cab, stack, or raised header)
• Turning radius or manoeuvring space needed to drive in and out

As a general guide, allow at least 600–900mm of clearance on each side of a machine, and 500mm overhead clearance above the highest point. Anything less makes day-to-day use frustrating.

For a standard agricultural tractor with an attached implement, a minimum internal width of 9–12 metres is often required. Larger harvesting equipment may need 15 metres or more.

Don’t forget to account for equipment you plan to purchase in the next five to ten years. It’s far more cost-effective to build a slightly larger shed now than to realise your new header won’t fit through the door in three years.

How to Size a Shed for Hay or Grain Storage

Hay and grain sheds are sized by volume, not just floor area. How you intend to stack or store your product directly affects the height and width you need.

How much hay can a shed store?

A standard round bale of hay is approximately 1.5m in diameter and 1.2m wide, weighing 250–400kg. Square bales vary depending on the baler. Stack height depends on your stacking method and equipment.

As a rough guide:

• A 12m x 18m hay shed can hold approximately 150–200 large round bales stacked three high
• A 15m x 24m shed can hold 300–400 round bales

For grain storage, the calculation shifts to tonnes per square metre based on pile height. Always factor in vehicle access — you’ll need enough internal clearance for a front-end loader or grain cart to operate safely inside the shed.

Does the Shed Need to Allow Vehicle Access?

This question affects both the door sizing and the internal height of your shed. If vehicles, machinery, or trucks need to enter and exit the shed, you’ll need:

• Roller doors sized to the widest and tallest vehicle
• Internal eave height of at least 4.5–6m for larger equipment (some applications require more)
• Drive-through access if you need to enter from one end and exit from the other without reversing

Open-front designs are popular for machinery and hay sheds because they eliminate door bottlenecks entirely and are often more cost-effective than fully enclosed structures with large roller doors.

What Site Factors Affect Shed Size and Placement in South West WA?

The size and placement of your shed isn’t purely a function of what goes inside it. Local site conditions and council requirements also play a role.

Key site considerations include:

• Setback requirements — your local council (City of Busselton, Shire of Augusta-Margaret River, or Shire of Harvey) will have setback rules from property boundaries, roads, and other structures
• Site slope — a sloping site affects your slab and foundation costs, which can influence how large or small you go
• Wind and weather exposure — South West WA properties in coastal or exposed rural areas need sheds engineered for higher wind categories
• Orientation — positioning your shed to take advantage of prevailing winds can improve ventilation for livestock and working comfort in a workshop

An experienced local shed builder will assess these factors as part of the design process and flag anything that could affect your plans before construction begins.

Should You Build Bigger Than You Need Right Now?

In most cases, yes — within reason.

The cost difference between a 12m x 18m shed and a 15m x 18m shed is often smaller than people expect. The additional steel and labour costs are proportionally lower than the cost of a separate extension later. Building to your five-year need rather than your current need is almost always the smarter investment.

That said, there’s a point of diminishing returns. Build what you can genuinely justify with a clear plan, not simply the largest structure that fits on the block.

A good builder will help you work through this honestly rather than just quoting you the biggest shed possible.

What Size Farm Sheds Does Westspan Build?

Westspan Sheds designs and builds fully customised farm sheds across South West WA — from compact rural lifestyle sheds to large multi-bay machinery and hay storage structures. Every shed is sized and configured to the specific needs of your property and your operation.

There are no off-the-shelf kits and no one-size-fits-all dimensions. The team works with you from the initial brief through to design, engineering, approvals, site preparation, and installation.

Westspan builds across Busselton, Margaret River, Bunbury, and the wider South West WA region, including Donnybrook, Dunsborough, Capel, Cowaramup, and Harvey.

Frequently Asked Questions About Farm Shed Sizing

What is the most common farm shed size in South West WA?

The most frequently requested sizes are in the 12m x 18m to 15m x 24m range for general-purpose farm sheds. Machinery sheds and multi-bay structures are often larger depending on the equipment being stored.

How high should a farm shed be?

For general storage and small machinery, a 3.6m eave height is often adequate. For tractors, headers, and larger equipment, 4.5m to 6m is more appropriate. Discuss your specific equipment with your shed builder before finalising the design.

Do I need council approval for a farm shed in South West WA?

In most cases, yes. The approval requirements depend on your local government authority, the size of the shed, and your property’s zoning. Westspan Sheds handles the engineering and approval documentation as part of the build process.

Can I add to my shed later if I need more space?

Extensions are possible but more expensive than building larger from the start. If you have a realistic plan for future expansion, it’s worth discussing this at the design stage so the shed can be engineered to accommodate it.

What’s the difference between an open-front and enclosed farm shed?

An open-front shed has no doors on the front face — it provides cover from rain and sun while allowing unrestricted drive-through access. Enclosed sheds offer greater security and weather protection. Many farm sheds combine both, with an open bay for machinery and an enclosed bay for fertiliser or smaller equipment.

How long does it take to build a farm shed in South West WA?

Timelines vary depending on the size of the shed, site preparation requirements, and approval timeframes. Westspan Sheds provides a clear timeline as part of the quoting and planning process.

Ready to Size Up Your Farm Shed?

Getting the right shed size starts with a conversation. The team at Westspan Sheds will walk through your property, your equipment, and your plans — and help you arrive at a design that makes practical sense for your operation.

Get a free quote or call 08 6722 8894 to talk through your requirements with the Westspan team.