Tips for designing a good farm shed
Careful planning and design is vital to get the best out of an expensive new farm building. Engineer Maurice Morrin of A&M Morrin Planning and Design has designed many farm sheds around the country. Here, he outlines his tips to Paul Mooney
Firstly, think about your farm as a business and decide whether or not your business needs will be met by the addition of a new building, advises Maurice Morrin. Assess all existing buildings on the farm with a fresh eye. Can existing buildings be adapted to suit your needs? Would it be more appropriate to demolish some older, inefficient buildings and erect a new shed in their place? Or should it go on a green field site?
To help, draw a scaled layout of the farmyard, including all pertinent features, and use this to decide on the future layout of the yard and the location of the new building. This bird's eye view is often the best way to decide where might be best to site a new building, as you get a full overview of the yard, unhindered by any obstructions, and it's a new perspective.
Once that decision is made, draw a scaled view of the intended layout of the new shed. Allow for all required features at this stage - it is easier to make changes on paper than when concrete and steelwork are in place.
Look at buildings on other farms that work well, and adapt from these for your own personal situation.
The guidance of your local agricultural adviser and of someone with experience in the design of farm buildings is invaluable at this early stage. They will have seen or designed hundreds of farm buildings for all types of farm enterprises and will have seen the benefits and drawbacks that arise.
Employing someone who can accurately design and advise on the layout of the new building is well worth it when you consider the overall cost of the building and its working life of 30 years or more. Be open to whatever new ideas they bring. Your own experience and advice is also valuable and should be taken on board - it is you, not them, who will have to work in this building.
Check the specs
Study the Department of Agriculture specifications for farm buildings - they're available on the Department website. They have good practical advice on building design, and also set out the legal minimum standard for farm buildings in Ireland.
The Danish Agricultural Advisory Centre provides a document entitled 'Housing Design for Cattle', which provides a large amount of practical advice on cattle housing and cattle behaviour. An English language version is also available on the website www.landbrugsinfo.dk/Byggeri/Filer/housing.pdf
You should read the wealth of information provided by Teagasc.
A key feature of a new farm building is height. For livestock buildings, for reasons of both animal welfare and easy machine access, there should be a minimum clear height of 3.65m (12ft), and preferably 4.265m (14ft). Ensure that the ventilation and roof slope requirements of S.101 of the Department of Agriculture are followed.
Vented cladding is the preferred way of getting inlet ventilation.
However, for larger and more intensive buildings, a clear opening immediately below the eaves, with a 400mm overhang to keep out rain, may also be required.
Straw stores usually need a minimum clear height of 5.5m (18ft), which will allow 4x4 round bales be stacked four high. Grain store height depend on use, but a general minimum would be 6m (19.5ft) to the eaves, rising to at least 8m (26ft) clear to ensure trailers can be tipped to full height within the shed.
Walls should be of mass concrete in all sheds, advises Maurice.
Block walls are not appropriate for the majority of farm buildings and, in any case, would usually cost as much as a properly constructed mass concrete wall.
Walls which will retain bulk materials should be designed accordingly and incorporate steel reinforcement in both the wall and foundation. It is important that the combined wall and foundation is of enough mass and strength for the material they will retain. For example, bulk fertilizer is heavier than grain or feed and requires a stronger foundation and wall.
When designing a new livestock shed, try to incorporate a new handling facility if the existing one is no longer adequate or else leave easy access to the existing unit. Do not leave the issue aside or as something you will think about after the shed is built. It can be most easily incorporated at the design stage.
Livestock and machinery must be allowed enough space. Ensure that cattle have at least 450mm (18 inches), and preferably 600mm (24 inches) feed space per head. There is no point in spending a large amount of money on a new shed and finding that cattle cannot easily feed.
Cubicle houses should have 2.4m (7ft, 10 inches) between rows to allow the cows to enter/exit cubicles easily and to allow machinery access if an animal falls within the shed. Ensure that there are at least two routes to the feed face. The feed passage should be as wide as circumstances allow.
A central feed passage should be at least 6.1m (20ft), and preferably larger, and an external passage, at least 9.15m (30ft).
Remember that it might not be someone as careful or as competent as you with machinery who might work in the yard.
Also, ensure that all areas of the yard can accommodate large contractor machinery.
The structural design of a shed will often be determined by intended use or by overall price. Portal frame buildings give large areas of clear space and are supremely adaptable. They are suitable for storage sheds, for sheep sheds that use moveable barriers and feed troughs, for straw bedded cattle sheds and straw lie backs to slatted sheds.
However, for the majority of slatted sheds and cubicle houses, they are not as cost effective as simple lean-to or back-to-back lean-to designs. This is because spans in these sheds are usually not large, and uprights are convenient for supporting feed barriers, pen divisions, etc.
When building an underground tank in an area with a high water table, make sure that ground water is adequately drained away from beneath the tank.
Otherwise, when empty, tanks can float, regardless of their size.
Maurice has seen this happen in tanks as large as 30m by 7.6m (100 by 25ft). It can cause tanks to fail and can be difficult and expensive to put right.
Ensure that clean rainwater is diverted to drains or soak pits.
There is no point in paying a contractor or spending time yourself spreading rainwater, which has got into tanks through careless design.
Maurice and Austin Morrin operate as A&M Morrin Planning and Design based at Oldtown, Donore, Naas, Co Kildare. Maurice can be contacted on 087-9231330.