What to Put Under Stall Mats

What You Put Under Horse Stall Mats Matters as Much as the Mats Themselves

Horse owners often spend significant time comparing mat brands and thicknesses, then give almost no thought to what is going on underneath them. This is a mistake. The substrate under your stall mats affects how the mats perform, how long they last, and how easy the stall is to maintain. A well-selected mat on a poorly prepared substrate will underperform every time.

WB Rubber and Turf Services provides professional horse stall mat installation throughout Texas, and substrate preparation is a core part of that process. Here is what you need to know based on the specific floor type you have.

Concrete Floors: The Most Common Scenario

Concrete is the most common base for horse stall mats in modern Texas barns. Most purpose-built equestrian facilities use concrete stall floors because they are easy to clean, resistant to digging, and durable. Here is what to do with concrete before mats go down:

What to Check First

• Level: Concrete floors in stalls should slope gently toward a drain or toward the stall opening, typically 1/8 to 1/4 inch per foot. This ensures drainage. Flat or bowl-shaped floors trap urine under mats.
• Condition: Check for cracks, especially active or widening cracks that indicate movement. Hairline surface cracks are normal and do not require repair before mat installation. Larger cracks or uneven settled sections should be addressed.
• Cleanliness: The concrete should be swept clean of all debris, shavings, and sand before mats go down. Any debris trapped under mats creates pressure points and can cause mats to rock.

Should You Use Any Underlayment on Concrete?

For 3/4-inch horse stall mats on properly prepared concrete, no additional underlayment is needed. The mats are thick enough to provide adequate cushioning directly on concrete. Adding foam or rubber underlayment between thick stall mats and concrete is generally not recommended: it can create a soft, compressible base that allows mats to flex and shift, creates seam movement, and traps moisture.

The exception is if your concrete has significant unevenness that you cannot level mechanically. A very thin rubber pad (1/8 inch or less) can bridge minor surface variations, but this is a workaround, not a preference.

Dirt Floors: The More Challenging Scenario

Many older Texas barns and run-in sheds have natural dirt or clay floors. Installing stall mats on dirt requires more preparation because dirt floors can shift, settle, and drain unpredictably. Here is what to do:

Grade the Surface

The dirt floor needs to be graded to a consistent level with appropriate slope for drainage. A flat dirt floor under stall mats holds moisture and creates an anaerobic environment underneath that accelerates organic decomposition, produces ammonia, and becomes unpleasant to deal with when you eventually pull the mats.

WB Rubber and Turf Services's flooring preparation services include soil assessment and grading to ensure your substrate is properly configured before mats are installed.

Compaction Matters

Loose or soft dirt compresses under the weight of a horse and the mats over time. This creates uneven settling that makes mats rock and develop gaps at seams. A compacted dirt floor -- either naturally compacted clay or mechanically compacted fill -- provides a stable base.

Consider a Layer of Compacted Gravel or Decomposed Granite

For problematic dirt floors, especially those with poor drainage, a 2 to 4 inch layer of compacted crushed aggregate (pea gravel, crusher run, or decomposed granite) under the mats significantly improves drainage and stability. This is a genuine improvement over bare dirt in many Texas barn environments where clay soils hold moisture after rain.

What NOT to Put Under Horse Stall Mats

A few common mistakes worth calling out explicitly:

• Bedding or shavings: Never lay mats directly over bedding. Shavings pack down unevenly, create pressure points, hold moisture against the mat backing, and shift around causing mats to migrate and create gaps.
• Sand without containment: Loose sand under mats shifts every time a horse moves, creating a perpetually uneven surface.
• Foam padding: Foam is too soft and compressible under stall mats. It creates an unstable surface, compresses under load, and traps moisture.
• Old, wet, or contaminated material: If you are replacing old mats, fully clean the substrate below before installing new mats. Old contaminated substrate left in place creates odor issues immediately under new mats.

Drainage: The Critical Variable

The most important property of a stall floor substrate is that it allows drainage. Whether you are on concrete with a sloped drain channel or on compacted gravel over dirt, liquid needs a path out from under the mats. Stalls that stay wet underneath develop ammonia odor, attract pests, and require mat removal for proper cleaning much more frequently.

In Texas, where horses drink and urinate more due to heat, drainage management is particularly important. Plan your substrate accordingly before the mats go down. Our horse stall mat product page has more information on mat options that support different installation approaches.

The Right Foundation Makes Everything Easier

Horse owners who pay attention to substrate preparation consistently report cleaner stalls, easier maintenance, and longer mat life. The work done under the mats before they go down pays dividends every time you pick up a manure fork. WB Rubber and Turf Services's installation team includes substrate assessment and preparation as a standard part of our stall mat service. Call us from Montgomery, TX to discuss your specific barn setup.

Troubleshooting Problems Under Existing Mats

If you have existing mats that are already installed and you are experiencing problems, here is a diagnostic guide:

Mats rock or shift: The substrate is uneven. This requires lifting the mats, identifying the high and low spots on the substrate, correcting them, and reinstalling. For concrete, this may mean grinding high spots or filling low spots. For dirt, this means regrading and recompacting.

Persistent ammonia smell despite regular cleaning: Urine has accumulated under the mats in an area with inadequate drainage. Lift the mats, clean both surfaces and the substrate below thoroughly with enzyme cleaner, allow full drying, and assess whether the drainage slope is adequate before reinstalling. If the floor slope is contributing to the problem, address it before reinstalling.

Mats curling at edges: This can happen on concrete floors with moisture vapor transmission. The moisture migrating through the concrete affects the underside of the mat differently than the top. A vapor barrier on the concrete before mats are installed prevents this. If mats are already installed and curling, they need to be lifted and a barrier applied before reinstallation.

Soft spots in the substrate under mats: Usually found in dirt-floor stalls where a horse has developed a preferred digging spot. The organic material from consistent digging degrades under the mat and creates a soft, unstable zone. The fix requires lifting the mat, excavating the soft material, filling with compactable aggregate, compacting properly, and reinstalling.

Long-Term Substrate Management

Annual mat lifting for full substrate cleaning and inspection is a practice that the most successful barn managers maintain consistently. It catches problems early, allows the substrate to fully air dry and off-gas annually, and gives you a chance to re-level any sections that have developed variation over the year. For Texas horse owners who want to protect their mat investment and maintain the cleanest possible stall environment, this annual practice is worth the labor involved.