Tips on building a manege
Menage or manege?
Well… if you say menage to a Frenchman he’ll think of households – as in ‘menage a trois’ – and certainly won’t connect you with horses. The correct term for a schooling area for horses is manege!
Selecting an appropriate size..
The most common size is a standard 40 x 20 metre school. This is quite adequate for most domestic needs, but you may need to extend it to 60 x 20 if you intend to do a lot of jumping or dressage. Don’t just add 5 metres here and there, because you will lose the standard circle sizes needed for dressage training. Commercial yards have completely different needs, and often have to cater for more than one lesson taking place at any time – which means a doubling or even tripling of the standard surface areas.The vast majority of maneges built are 40 x 20 metres.
Type of construction…
There are a number of essential aspects to a manege. Each of these must be present in one form or another to enable the finished product to work properly. If you cut money off the project, you will end up compromising one or another of these stages, with the inevitable result that you have a wet, soggy school in winter.
Initial site selection,excavation and levelling…
Site selection is not just an aesthetic process. You need to ensure that it is high enough to be drainable – and that there is sufficient fall on outlet pipes to be able to carry this water to a nearby main drainage channel – nearby stream, ditch or stormwater drain. Bear in mind that the volume of water that is produced by a well built manege in even an average rainstorm is quite phenomenal – a 4 inch outlet pipe can frequently be seen to gush water at at flow rate of several thousand gallons an hour.
It is vitally important to ensure that the surface you are to work with is flat. Any material which is used to fill low areas MUST be compacted and allowed to settle properly – natural settlement of soil and clay is a process that can take up to 12 or 18 months to achieve full compaction. Initially you can expect slumping and settlement of up to 25% of the initial volume. This means that if a contractor digs out a metre of material and dumps it on the ‘downside’ of a slope, you can expect that side to end up settling down a good 6 to 12 inches depending on how well the contractor compacted it when he put it there. If you dont allow for this slumping, your school surface will end up with dips and hollows in it, or at worst, will slope badly in the direction of the filled area. To avoid this, you can make up areas that need filling with hardcore instead of soil, which doesnt slump significantly. This then leaves a problem of disposal of excavated material – often we can find a hollow in a field somewhere that needs filling, or at worst, it has to be carted away.
Of course, there is no reason why a relatively flat site cannot have a manege built on top of it – the fencing is used to retain the various layers, by using timber or concrete boards attached to the fence posts. Bear in mind that the total thickness of various layers can be 350 or 400mm.
Note that topsoil should always be removed.- it contains a lot of organic material which rots and blocks drainage.
Main drainage structure
There are a number of options available for a drainage structure – but they all have one thing in common – channelling water away from the surface as quickly as possible. The most common arrangement is to run a central ‘spine’ down the middle of the school – the centre line – and pipes are then laid at an angle to this in a herringbone pattern, which reach out to the outer edges of the school. The herringbone pipes should be laid at no more than 5 metre intervals. All drains should have a minimum gradient of 6mm per metre length, giving the total fall in drainage from one end of a 20 x 40 school of about .25 of a metre, or 10 inches. You can vary this pattern if, for example the school is built on a hillside – the drains can be laid to discharge water onto the downslope side. Care must be taken to ensure that you dont end up with a concentrated gush of water being discharged onto the hillside and causing erosion.
Drains must be the perforated plastic 100mm land drainage type, laid in a trench roughly twice the depth of the pipe, which is lined with geotextile membrane. The pipe is laid in the trench, which has been lined with membrane, and the trench filled with clean pea gravel. The central spine is then connected to a discharge main, usually a solid 4 inch stormwater pipe is used, which is then directed into the nearest drainage channel such as a ditch.
Once the drainage channels are complete, the entire area is covered in geotextile membrane. This seals the drainage channels and prevents mud from mixing with either the drain channels or the next layer to be added – the actual porous drainage bed lying underneath your surface material.
This is an essential part of any manege – it acts as a reservoir for water falling in heavy downpours, and allows rapid dispersal of water from the working surface. It must be non degradable material – one of the most popular used these days is clean road planings. Crushed rock is ideal – BUT – do NOT use limestone, which gradually breaks down and produces a very sticky, muddy clay which blocks the drainage system very quickly. Igneous rocks such as granite and dolerite, and slate being ideal. The total thickness of this layer should be at least 100mm (4 inches) or more. Translated into volumes and tonnes, you are looking at around 80 cubic metres, (at 100mm thickness) or roughly 180 tonnes – assuming decent sized trucks carrying 12 to 17 tonnes, you are going to need at least 10 truck loads.
On top of the drainage bed, you need another layer of membrane. This keeps the working surface completely separate from the drainage bed. There are two reasons for doing this – one, it is then impossible for the work surface to fill the pores of the drainage bed and block it. Two – you are at liberty to change surfaces simply by raking the material off the membrane layer, and replacing it – the drainage bed is still kept intact and fully functional.
This is the point at which we see the most variance. To some extent it is covered in the next section, selection of appropriate surface, but we’ll briefly discuss surfaces here too. To protect the membrane which covers the drainage bed, we usually use a layer of clean, washed silica sand. . It usually comes from the quarries in which are worked for foundry sand, and contains little or no fines and impurities. You need to allow for a depth of at least 50mm, preferably 100mm. Translated into volumes and tonnes, you are looking at around 80 cubic metres, (at 100mm thickness) or roughly 140 tonnes – assuming decent sized trucks carrying 12 to 17 tonnes, you are going to need at least 9 or 10 truck loads.
What surface to select…
This is a tricky question to answer at the best of times. We always say to people that they need to go and ride as many surfaces as they can before making a decision. If you can’t ride it, ask people. Try to ask professionals who know the effect the surface is having on their horses and riding – and ask showjumpers as well as dressage riders. You will need to give thought to the use to which your manege is to be put – if you are mainly jumping, it is more important to protect the membrane with sand, and to select a surface that gives a little natural spring – if dressage, try to avoid anything that your horse sinks into ar that causes him to drag his feet. In general, surfaces for jumping tend to be bigger, springier materials than those for dressage. A silica sand mix is always a good surface for flatwork.
* A suspect material not to use is bark or woodchip. These work fine for a year or two, but ALWAYS break down into a soggy mess after a year or two. You are dumping tonne after tonne of organic material onto your drainage bed that wants nothing other than to rot down into lovely compost – nice fine, crumbly, clayey brown stuff that clogs everything! Vendors will do anything to convince you that its treated, and wont break down – but it always does in the end – at which point you are left with a blocked drainage system, and a very dusty surface in summer.
* Although not really ‘inappropriate’, shredded tyres are fast becoming obsolete because of environmental concerns. If you are offered shredded tyres – think long and hard before getting it – odds are that someone is trying to offload what is soon to be classified as hazardous environmental waste. Its already banned in Europe.