What size farm shed do I need Ireland? Quick Answer: The right size farm shed in Ireland depends on what you’re using it for. As a rough guide: livestock sheds typically need 4-6 m² per cow (cubicle) or 8-10 m² per cow (loose housing), so a 30-cow shed needs around 180 m². Hay sheds size around your annual bale storage — roughly 1 m² per round bale stacked three high. Machinery sheds need 6m minimum eaves height for modern kit and roughly 30 m² per tractor with implements. Slurry storage is calculated at 0.33 m³ per dairy cow per week of storage required (most Irish farms need 16-22 weeks). Always build for the operation you’ll have in 5 years, not just today — extending later costs more than building 20% bigger now.

The most common regret in Irish farm building isn’t spending too much money — it’s building too small. Five years after the build, the shed’s too tight, machinery’s outgrown the door, livestock numbers have crept up, or the planning exemption rules have changed and you wish you’d used your full entitlement first time around.

This guide walks you through how to actually size a farm shed properly in Ireland — what to think about for each building type, what mistakes to avoid, and how the 2026 planning exemptions and TAMS 3 grants affect what’s worth building.

[Image suggestion: insert a Sullivan Steel completed agricultural project showing scale. Alt text: “What size farm shed do I need Ireland — Sullivan Steel completed agricultural building in Co. Wexford”]

What size farm shed do I need Ireland, Start With What the Building Is Actually For

This sounds obvious but it’s the single biggest mistake we see at Sullivan Steel. Farmers come to us with a number in their head — “I want a 60×40 shed” — but when we ask what they’re using it for, the conversation reveals that 60×40 is wrong for what they actually need.

Different uses have completely different sizing logic:

• Livestock sizes around animal numbers and welfare requirements
• Hay and silage sizes around annual yield and bale dimensions
• Machinery sizes around eaves height for modern kit
• Slurry sizes around stocking density and storage period requirements
• Multi-purpose sheds size around whichever use needs the most space

Start with the use, then work back to the dimensions. Not the other way around.

Livestock Shed Size

For animal housing, the floor area per animal depends heavily on the housing system and the animal type. Here are working rules of thumb for Irish farms:

Dairy Cows

• Cubicle housing: 4-6 m² per cow (cubicles + passageways)
• Loose housing/straw bedding: 8-10 m² per cow
• Calving pens: 12 m² per cow (separate from main housing)
• Standard cubicle size: 2.4m long × 1.2m wide
• Feed passage: Minimum 4.2m wide for two-row layouts

For a typical 50-cow dairy herd in cubicles, you’d need around 250-300 m² total — which is now within the 300 m² animal housing planning exemption introduced in December 2025.

Beef Cattle

• Slatted finishing: 2.5-3 m² per animal
• Straw-bedded: 4-5 m² per animal
• Suckler cows: 6-8 m² per cow with calf

Sheep

• Indoor lambing: 1.2-1.4 m² per ewe
• Loose housing: 1.0-1.2 m² per ewe
• Lambing pens: 1.8 m² per ewe individual pens

Calves

• Group pens (under 8 weeks): 1.5 m² per calf minimum
• Single pens (under 8 weeks): 1.8 m² per calf
• Group pens (8 weeks to 6 months): 1.7-2.0 m² per calf

Pigs and Poultry

Stocking densities are tightly regulated. Talk to your agricultural adviser for current requirements — they change with welfare regulations and we don’t want to give numbers that might be out of date by the time you build.

Hay and Silage Shed Sizing

Hay and silage sheds size around what you actually store annually:

Round Bales

• 4×4 round bale: Takes around 1 m² of floor space if stacked properly
• Stack three high: Maximum efficient stack — beyond that, bales at the bottom compress
• Bale ventilation: Allow 100-150mm gaps between rows in stored bales

For a farm storing 200 round bales annually, you’d need approximately 70-80 m² of floor space stacked three high, plus access space for loading.

Square Bales (Conventional)

• Standard bale: Roughly 0.06 m³ each
• Stack height: Up to 4-5m possible
• Approximate storage: 200-300 bales per cubic metre of stack

Silage

• Pit silage: Calculated by tonnage requirement (typically 8-10 tonnes per cow per year for dairy)
• Bale silage: Higher density than dry bales, plan for stacking only two high
• Access: Needs hard standing and turning circle for the loader

Hay Shed Practical Considerations

• Eaves height: Minimum 5.5m for round bale stacking with overhead clearance
• Open-front design: Helps prevent overheating and fire risk
• Ventilation: Bottom-vented if walled, otherwise rely on open structure
• Door width: Minimum 4m for telehandler access

Machinery Shed Size

This is where farmers most often build too small. Machinery has grown significantly in the last 20 years — a shed sized for the 1990s tractor fleet often won’t fit a modern 6-cylinder tractor with mounted implements.

Critical Dimensions

Eaves height:

• Minimum 5m for standard farm tractors with rotating beacons
• 6m+ for high-cab modern tractors with safety beacons and large implements
• 7m+ if you ever plan to bring in a combine, large slurry tanker, or self-propelled mower

The most common machinery shed regret is too-low eaves. You can extend the floor, but raising the roof later is rarely practical.

Door dimensions:

• Minimum 4m wide × 4.5m high for standard kit
• 5m wide × 5m high is safer for modern tractors with front-mounted equipment
• Sliding doors work well for wide openings; roller shutters for narrower

Floor space per piece of kit:

• Tractor with mounted plough: 6m × 8m parking footprint
• Tractor with large trailer: 6m × 12m
• Combine harvester: 5m × 11m, plus access
• Self-propelled slurry tanker: 4m × 10m

Multi-Tractor Layout

For a farm with 2-3 tractors plus standard implements (plough, harrow, mower, fertiliser spreader), plan for:

• 3-bay shed minimum at 6m × 8m per bay
• Total footprint: Roughly 18m × 8m = 144 m²
• Extra storage for spare parts, fuel, oils, smaller equipment

Slurry Storage Sizing

This is calculated by stocking density, animal type and storage period required:

The Basic Calculation

Slurry production per dairy cow: approximately 0.33 m³ per cow per week

So for a 50-cow herd needing 18 weeks of storage:

• 50 × 0.33 × 18 = 297 m³

For beef cattle, the calculation is roughly 60% of the dairy figure per animal.

Storage Period Requirements

Required storage period varies by region and Nitrates Action Programme zone:

• Zone A (low-vulnerability soils): 16 weeks minimum
• Zone B (medium-vulnerability): 18 weeks
• Zone C (high-vulnerability soils): 22 weeks

Talk to your agricultural adviser for your specific zone requirement.

Practical Slurry Storage Design

• Tank depth: Typically 2.5-3m deep
• Above-ground tanks: Easier to inspect, faster to empty
• Below-ground tanks: Less visual impact, no freezing risk
• Agitation access: Critical — plan for tanker access on the right side
• Safety: Fencing, covers, and ventilation requirements are non-negotiable

The new December 2025 planning exemption allows stand-alone slurry storage up to 1,000 m³ per structure (1,500 m³ farm total) without planning permission — a significant change for farmers needing extra capacity quickly.

Don’t Forget Future-Proofing

Whatever you’re building now, ask three questions:

1. What will my farm look like in 5 years? Herd expansion, machinery upgrades, succession planning, diversification. Build for the future operation, not the current one.

2. What’s my maximum planning exemption allowance? Under the new December 2025 rules, you can build up to 300 m² animal housing per building, with a 450 m² cumulative limit across the holding over 4 years. If you’re going to build, use your full entitlement first time — splitting it into two smaller exempted builds later is often less efficient.

3. What’s the TAMS 3 grant ceiling? TAMS 3 has a €90,000 investment ceiling per holding (€160,000 for partnerships). Plan your build to maximise grant utilisation within this ceiling. For full details, see our TAMS 3 grant for steel sheds guide.

Multi-Purpose Sheds vs Dedicated Sheds

A common question: should you build one large multi-purpose shed or several smaller dedicated sheds?

One Large Multi-Purpose Shed

Advantages:

• Cheaper per square metre than multiple smaller buildings
• Easier to extend/adapt later
• Single planning consideration
• Single set of services (water, power, drainage)

Disadvantages:

• Mixing uses can compromise each (e.g. dust from machinery near hay)
• Disease/welfare considerations for livestock
• Larger footprint in one location

Multiple Dedicated Sheds

Advantages:

• Each shed optimised for its use
• Better disease control and welfare separation
• Distributed risk (fire, flooding affecting one shed only)

Disadvantages:

• Higher cost per square metre
• More planning considerations
• Multiple service connections

Sullivan’s Honest Advice

For most working farms, a single large multi-purpose shed with internal partitions usually wins on cost and flexibility — unless there’s a specific reason (livestock disease control, machinery dust issues, succession planning across family members) to separate uses.

How the 2026 Planning Exemptions Affect Sizing

Farm shed size guide Ireland agricultural shed dimensions Ireland, the new exemptions changed the maths significantly:

For animal housing: Up to 300 m² per building (was 200 m²), 450 m² cumulative across the holding over 4 years. If you can size your build at 300 m² exactly, you stay exempt — but 305 m² means full planning permission.

For slurry storage: Up to 1,000 m³ per structure (1,500 m³ farm total). For most farms under 100 cows, this single exemption covers their entire storage requirement.

For other agricultural use (machinery, storage): Up to 900 m² cumulative (unchanged) over 4 years. Setbacks and height limits still apply.

For full details on the rules and what conditions still apply, see our guide to the 2026 planning exemption changes.

Common Sizing Mistakes to Avoid

After years of building farm sheds across Ireland, the most common sizing mistakes we see:

1. Building for today’s herd, not tomorrow’s. Five years from now, your herd will likely be larger. Building 20% bigger now is significantly cheaper than extending later.

2. Forgetting feed passage and access. A 50-cow cubicle shed isn’t 50 × 4 m² — it’s 50 × 6 m² once you add feed passages, walkways and crush areas.

3. Sizing the door wrong. Tractors with front-mounted equipment need wider, taller doors than people expect. Get the dimensions of your largest current and future machinery before deciding.

4. Skimping on eaves height. It’s the most regretted dimension. An extra metre of eaves costs little at build time but adds enormous flexibility for life.

5. Ignoring slurry storage requirements. Some farms build the livestock shed perfectly, then realise they’re 100 m³ short on slurry. Plan both together.

6. Building under the planning exemption limit unnecessarily. If you actually need 320 m², you might as well apply for full planning and build 400 m² — the planning effort is similar but the building is more useful long-term.

7. Not factoring in TAMS 3 grant ceilings. A €100,000 build is partially funded by TAMS; a €110,000 build is still partially funded by TAMS at the same ceiling. Make sure you’re not just over the cap unnecessarily.

How Sullivan Steel Helps With Sizing

At Sullivan Steel, we approach every farm build with the same process:

1. Site visit and consultation. We walk the site, talk through your operation, and ask the questions that reveal what you actually need (not just what you initially asked for).

2. Sizing recommendations. Based on your numbers, your operation, and your future plans — not off a template. If your build needs something a standard shed cannot cover — an unusual span, integrated tanks, or a specialist structure — we handle it as bespoke steel fabrication.

3. Planning exemption advice. We help you maximise what you can build under the new exemptions, including Section 5 declarations where useful.

4. TAMS 3 coordination. We quote against scheme reference costs and coordinate with your agricultural adviser as needed.

5. Detailed written quote. Steel spec, dimensions, cladding, doors, exclusions — all in writing.

For more on what to expect from a steel shed build, see our guide to building a steel shed on your farm in Ireland.

FAQ

Q: What’s the most common farm shed size in Ireland? The most common new-build farm shed in Ireland is 60×40ft (approximately 18m × 12m = 216 m²). This sits comfortably within the current animal housing planning exemption (300 m²) and works well for medium-scale dairy and beef operations.

Q: How much space does a dairy cow need in a cubicle shed? Roughly 4-6 m² per cow including cubicles, feed passages and walkways. For a 50-cow herd in cubicles, plan for around 250-300 m² total floor area.

Q: What size machinery shed do I need for a typical farm? For a farm with 2-3 tractors and standard implements, plan for a 3-bay shed at roughly 18m × 8m (144 m²) with minimum 6m eaves height and 5m × 5m doors.

Q: How much slurry storage do I need on my farm? Slurry production is approximately 0.33 m³ per dairy cow per week. Multiply by your storage period requirement (16-22 weeks depending on Nitrates zone). A 50-cow dairy herd typically needs 250-300 m³.

Q: Can I build a farm shed larger than 300 m² without planning permission? No. Under the December 2025 planning exemptions, individual animal housing buildings are limited to 300 m² for exemption. Anything larger requires full planning permission — but the exemption limits for other agricultural use (900 m² cumulative) are different.

Q: Should I build one large shed or multiple smaller sheds? For most working farms, a single large multi-purpose shed wins on cost and flexibility. Multiple dedicated sheds only make sense if you need specific separation (disease control, fire risk, succession planning).

The Bottom Line

Sizing a farm shed properly comes down to three things: knowing what you’re really using it for, planning for the next 5-10 years rather than just today, and making the most of current planning exemptions and grant schemes.

A shed built 20% bigger than today’s needs is almost always cheaper than the eventual extension. A shed sized perfectly for current planning exemptions is almost always more grant-efficient. And a shed designed around your actual operation — not off a template — is the only one that actually works for the next 30 years.

If you’re planning a farm build and want to talk through the right size for your specific situation, get in touch with Sullivan Steel. We’ll come out to the site, walk through your plans, and give you an honest quote with sizing recommendations based on what you’ll actually need.