Adding the Horse Exerciser Footing to the track is the final important step in completing your machine. In our prior Horse Exerciser Track article, we review construction considerations to develop a solid foundation for the sub base and the base of the pad to achieve proper track drainage and track support for the horses. The footing is the final construction step, and will provide your equine athletes with proper traction and impact absorption as they exerciser in the machine. There are many excellent footing options available and each offer cost and performance attributes to consider.
The purpose of the footing is to provide the appropriate impact absorption and support as a horse works around the track. Managing the footing and proper shoeing significantly reduces impact loads to the horse’s joints and ligaments. Barrey, Landjerit and Wolter studied shock and vibration at the hoof with different track surfaces, including asphalt, gavel, gravel+sand, sand, sawdust and sand with various mixes. Good performance is achieved with sand and sand with mixes of softs and is one of the most common fill materials used in Eurocisers. It also tends to be cost effective and locally available. There are a number of excellent synthetics that create good impact absorption and support – they do require greater investment.
The footing material must provide sufficient traction to give the horse hoof purchase as they exercise. The footing must provide this traction while absorbing the impact loads during the exercise. If the footing is too hard, the impact loads are not absorbed and can result in concussive injuries. If the footing gives too much (low shear force), the horse must work harder to generate movement and result in fatigue on ligaments and tendons, causing potential injuries. Over compensating for one attribute can often sacrifice the second attribute. It’s important to achieve a balance of traction and impact absorption.
The footing material will see constant use and can break down over time. It’s important to consider the maintenance cycles and useful life of your footing to get the best performance and lowest life cycle cost before replacement. As the footing breaks down, undesired side effects can form. Soft sands and sands with high silt content that drain proper when exposed to rain, can loose their porous properties as they break down, causing lack of good drainage. Worn footing can also loose some impact absorption properties. Not all sand, synthetics and softs are equal. Investigate the best choices for your track to get the best performance for your horses.
There are a number of synthetic options available on the market that provide great traction and absorption qualities. The investment cost for synthetic footing is higher than alternatives such as sand. And if the material is not available local there are additional shipping costs to consider. We recommend working directly with the specific footing manufacturer to understand the appropriate solution for your track, and get references to understand the proper set up and maintenance of the footing system you plan to invest in. We reference a number of suppliers at the end of this article.
Sand is a great footing material choice, and if specified properly, is one of the best cost and performance options available. A 3-4 inch sand depth is required for the Eurociser and sets on top of the compacted base.
The quality and type of sand varies greatly region by region – not all sand is equal. Soft sand breaks down quicker. High silt content generates more dust. Greater clay content tends to have greater silt content. Round sand does not provide the same traction properties compared to angular sand. Sand can even be categorized differently based on the region you buy it. Therefor it is important to be specific about the characteristics you want in the sand. Below are the more important characteristics to be specific about when purchasing your footing.
For starters, specify sand that meets ASTM C-33. Most quarries carry this sand grade as it’s a standard construction grade, and a common sand grade used for horse arenas. The sand size ranges .05 mm to 2 mm in size, (a fine, medium and course sand mix). The specification provides requirements for the sand mix make up and limits the amount of clay and silt within the sand.
It’s possible specify washed sand to limit the silt content and clay content further. Poor quality clay has high silt content, and silt offers no benefits. In fact, silt is the larger contributor to dust production, and washing the sand allows you to remove the majority of silt. It is worthwhile to add back a quality clay material with low silt content. The clay provides impact absorption properties and helps absorb water to keep the sand moist. The mix should be 80-90% sand, 10-20% clay.
Sand has different hardness levels based on the mineral composition. Quartz/Silica sand is more durable and the preferred choice over Mica or Feldspar type sands. Sub angular and angular sand is also recommended over round sands. The angular sand interlocks under pressure, creating better traction for the horses.
How do you confirm the sand meets the requirements / characteristics you plan to buy from the supplier? Getting references from local arenas can be helpful to see how the sand is performing. Footings Unlimited suggests a simple test by taking 2 inches of sand in a glass jar, add water several inches above the sand, mix and see how much sand falls out of solution after 1 minute. Measuring the new level of sand gives a good percentage estimate of how much of the footing is sand. The remaining soluble dirt, clay and silt stays suspended until it has time to settle. You want 80-90% of the material to be sand for your footing.
Rubber can be added to the sand mix to further increase the impact absorption properties of the footing. Rubber from recycled tires is most readily available and offered by numerous suppliers. Make sure the rubber is clean of debris and has no foreign material (no metal). Its possible to buy rubber material produced just for horse arenas as well. It’s important to not overload the footing with rubber, or too much give is developed within the footing. The rule of thumb is to use 1-2 pound per square foot of surface area. Depending on the size of the machine, plan 1500 pounds to 3000 pounds of material.
Wood Chips and Fiber
Wood chips and fiber are also an option. Care must be taken to keep the track moist as the impact absorption is developed from the wood when it is damp. Dry wood is stiffer and breaks down quickly when the horses work on the track. Hard woods work best for durability. However, wood chips do break down quicker and require periodic replenishment maintenance cycles.
Adding a rubber mat lattice layer below the footing / above the base is a great way to build a cushion layer to the track. About 3 inches of sand footing is added on top of the mat, and sand fills the gaps of the mat. It’s important to have a secure way to keep the mats down and have drainage paths beneath the rubber mat to flush moisture through the sand and mats.
Your track does require maintenance. It’s important to drag and rake out the footing to re-level the material and mix materials, especially in high traffic areas. It also prevents the horses from wearing down the footing to the point where the horses are working on the base of the track. If the horses reach the base, the absorption benefit is removed, and it’s possible to break down and wear the base resulting in further track maintenance.
Maintaining the moisture level in the footing is important as it keeps the material resilient to achieve the impact absorptions properties desired. The moisture content should be maintained at 5-10% by volume (water to footing content). The moisture also keeps the dust level down as the horses work on the track. If your uncertain how to judge the moisture content, pick up a digital moisture meter like a General Tools MMD4E meter. They are on line or at your local hardware store in the irrigation supplies section for about $50. Adding a ground based sprinkler system can make managing the moisture level easier. By establishing your water cycle and understanding the moisture content results, you can simplify the water maintenance cycle of the track.