Understanding Track Surfacing Systems, Project Timeline, and Maintenance
Choosing the appropriate type of surfacing for your running track design is critical to ensuring optimal performance and the safety of your athletes. It is important to begin the planning process in late summer or early fall to be able to accommodate the spring track season.
Landscape Architects Tim West, PLA, and Clay Schneckloth, PLA host this webinar episode on running tracks. They will outline details to help get you started on your planning, discuss running track systems, design processes, construction methods, costs, and leave you with tips that will help you avoid issues during each step in the process.
- Typical Track Cross Section (0:49)
- Common Track Surfacing Systems – SBR Base Mat System (1:41)
- Common Track Surfacing Systems – EPDM Base Mat System (2:35)
- Combination Track Surfacing System (3:14)
- Special Design Considerations (3:59)
- HMA Surface (5:23)
- Running Track Design Schedule (6:29)
- Running Track Construction Schedule (7:40)
- Running Track Cost Considerations (8:17)
- Long-Term Maintenance Plan for Running Tracks (9:56)
Typical All-Weather Track Cross-Section (00:18)
We’re going to start with a breakdown of some of the tracks surfacing and track construction components associated with those specialty surfaces. Synthetic tracks are something that sometimes falls into the background. It’s really difficult to keep a close eye on the track because it’s something that’s always there. It’s usually been constructed a couple of years ago at your school or in your community. So a lot of times, people aren’t keeping as close of an eye on that facility as they should be.
Most of those consist of a cross-section that looks like the one that we show on the screen here. So whether you’re building a new track or you have an existing one that’s been built within, let’s say, the last 15 to 20 years, it probably looks something like this. It’ll consist of about a 1/2″ or 13 mm track surfacing on a 4″ asphalt base. That all sits on top of a granular base. That could be sand. It could be crushed rock. We want that to freely drain to an interior perforated drain tile that would go around the interior circle of the track. About 90 to 95% of the tracks out there have this type of cross-section. It’s a tried and true method for construction on tracks. The important part is making sure the soils and the drainage are done to the appropriate method.
Most Common Track Surfacing System – SBR Base Mat System (1:41)
The most common tracks surfacing system is the base mat system, which consists of some sort of a rubber granule and a polyurethane full pour, which gives it a consistent depth of 13 mm. SBR rubber is a type of synthetic rubber, but it’s usually generated from recycled tires and turned into this crumb rubber for that product. Due to the recycled nature of SBR base mat, it’s only available in black, but it’s the least costly option. It has good resiliency. The polyurethane and the rubber granules bond well together. There is some permeability associated with these systems, so you have to make sure that the asphalt base is built correctly with no ponding so that you’re not experiencing any delamination. But we’ll get to that in a little bit later in the webinar.
Common Track Surfacing Systems – EPDM Base Mat System & Base Mat with Structural Spray (2:35)
The next step up would be a base mat system, but it would be out of an EPDM rubber. The difference in that is that EPDM is a synthetic rubber, but it’s more of virgin or new rubber. So you can colorize that and get almost any color that you’d like on that. The same thickness is established that 13 milometers, but it gives you a large range of aesthetics that you can include in your project. The new aspect of the material is more expensive and recycled material. And then the colorization also costs more. So all in all, the product costs a little bit more than the base mat system to add color to it. We’re also starting to see some combination systems in there. The base mat with structural spray shown on the right you can get by with a little less SBR rubber or the base mat system at 10 mm and move in with a structural spray right away instead of putting it on after the track’s been established for a while. The advantage of this is that a structural spray can hold up to traffic a little better, is more resistant to track spikes, and you can add color to it because it is an EPDM product through the rubber spray. The disadvantage, of course, is that it costs more, and there is some limit to the number of structural sprays that you can put on tracks. So you kind of get the best of both worlds here. But you do limit yourself to the number of structural sprays in the future.
Special Design Considerations for Running Tracks (3:59)
The special design considerations that we take into account mostly revolve around making sure the base is solid. Soil borings are an important aspect to determine soil characteristics. We’re specifically looking for expansive soils and any types of high water table or wet soils where it might indicate we have a water problem that would potentially perch underneath our track pavements. We’re also looking to make sure that we’re draining surface flow away from the track. So if there are any types of hills or slopes that are coming down towards a lower track, we would want to install subdrains to pull that water away from the track and leave that pavement high and dry so that there’s a low chance of water infiltrating and collecting in there and then freezing and thawing over the winter months, beyond establishing subdrains into those conditions. We can also chemically stabilize those subbases if we have a tight schedule or if we just cannot disk and dry out those subsoils by adding fly ash or a similar product incorporating it into this subgrade. We would recommend that we carry some allowance for that anyway because even if the soils are pretty good, we would want to potentially use it if we have an in-ordinary wet spring or the schedules extra tight where we have to have the track done and opened by a certain time frame.
I know you’re going to get into discussions here a little bit later on the fly ash, but that is a costly item that seems to be a surprise to a lot of people when we bring that up. Also, on the HMA mixed design. Tim’s been talking about the top surface portion of it. The HMA, the base that holds this top surfacing, is important. There are a few different things that we make sure we talk about here is that top of that HMA surface, the asphalt, needs to be a smooth surface to be able to put the top coating on top of it. So we’ve designed and worked with asphalt suppliers too on different mixes for this top surfacing of the asphalt. We usually use a 3/8″ rock in that mix to be able to create that smooth surface. By doing that smooth surface, there’s a possibility of some birdbaths. Even with a rougher surface, there’s a possibility of birdbaths. So the importance of making sure we get this at a 1% cross slope and as tight as you can without the bird baths is very critical.
Running Track Design Schedule (6:29)
So as we’re moving into the design schedule, we’ve started the process. We’ve looked at the design of what the actual track is. Now we’re looking into when should we start talking with you and getting this project figured out to move forward into construction. Most of our projects we need to be starting mid-May, and they happen over the summer months. Track is a spring event, so we try and coordinate with the different school districts on the timing of construction. Most of this construction happens over the summer months. We back into bidding this project in-between January, February would be the ideal situation. We’d like to get this out to bid. So which means we’d have to back into a Topo survey, getting the ground figured out what we have in that area, getting the geo-tech work taken care of before that. So we’re talking about October, November, and December of getting the survey geo-tech work, so we can get into doing design getting into the bid of January and February. It does take 10-12 weeks to get the design figured out and approved. A lot of times, we’ll need to go to a city for approval or school boards for approval too.
Running Track Construction Schedule (7:40)
Which leads to the construction schedule. The HMA really needs to be installed by July 15th. It does have a 20-day curing time on it before we can start putting the surfacing on it. Typically it takes them about four to five days to get that surface, always weather dependent on that and getting the surface down on top of the asphalt. Our nighttime temperatures need to be above 45 degrees, and once we get into mid-October, the weather is always up in the air. So we want to try and get all of that taken care of before October, if possible.
Running Track Cost Considerations (8:17)
When we started talking about budget considerations, a couple of keys we like to bring to your attention. There are a lot of discussions that’ll need to occur on how the D areas are treated. That’s the infield area between the playing field and the track curvature. There need to be some decisions made as to whether you’re going to continue to use that in a natural turf format. Do you want to do synthetic turf in the D area, or do you want to complete that with track surfacing, which includes asphalt and drains? We’re usually encouraging people to pave those D areas cause it allows for some multipurpose space. You also can put your high jump and long jump facilities in those within the track circle, and it usually is a little bit cheaper than synthetic turf if you’re considering that. Budget numbers for a new track system, which means going from tearing out the old track and putting in the new rock base, new tiles, new asphalt, pavement, it’s about $600,000 to $700,000. So we’d encourage you to carry that as a rule of thumb budget number. As you start to think about new track construction, if you’re asphalt base is in good shape or relatively new, and you’re just looking to replace your base mat or track surfacing system, $160,000 to $170,000 will probably do it. That allows for some repair of cracking within the surfacing. And if you just need a structural spray, $90,000 as a budget is a number that we’d recommend, which does include a little bit of crack repair as well.
Long-Term Maintenance Plan for Running Tracks (9:56)
Long-term maintenance is important on the track. Sometimes it’s deceiving when you aren’t out there all the time, and the majority of the track is used by either the public or potentially just only by the track team. Yearly inspections are important. You can identify any sort of cracking and repair it right away, so those small cracks don’t turn into large ones. We’d recommend that you walk that with a qualified contractor that specializes in those track surfacings and track repair methods. We’d recommend you also consider a structural spray in years five to seven. That’ll be dependent upon wear on the track and usage. That will allow you to gain another five to seven years over the life of that track. If you let it go all the way without a structural spray, we’ve been seeing a base mat wear out roughly in years 12-15. At that point, you may have to replace the base mat entirely. If you have the structural spring and your 5%, you might be able to get by with another structural spray. So when you start to consider numbers like $90,000 for a structural spray, those numbers need to be included in any projection of budgets down the road. It’s not just about the installation initially, but having a maintenance budget that you can invest into overtime and hit some of these dates.