Water might be necessary for life, but it’ll spell the death of your parking lot if it doesn’t drain off the asphalt efficiently. Standing water will inevitably break down the asphalt over time, eventually deteriorating the bonds between the asphalt binder, sand, and rocks that together form the pavement.

Water can also accumulate below the surface of the asphalt if your parking lot has poor drainage. When that occurs, subsurface moisture will progressively weaken the subgrade and aggregate materials, reducing the pavement’s ability to handle traffic load. Ultimately, potholes will form, cracks will materialize, and your once-gorgeous parking area will become a hazardous eyesore.

Fortunately, your asphalt parking lot doesn’t have to fall victim to the consequences of water accumulation. When you understand how to encourage efficient water drainage and implement the appropriate tactics, you’ll enjoy a long-lasting, structurally sound, and aesthetic parking lot.

Let’s take a look at what you need to know.

Ensure the Pavement Has Adequate Slope

The slope of your parking lot is one of the most crucial elements in the fight against water accumulation. Adequate slope will prevent water from pooling on the surface of the asphalt, which will naturally help reduce the risk of pothole development. At Bituminous Roadways, we recommend a minimum of a 1% slope for new asphalt pavement, but depending on your location, you may need more.  

Tend to Routine Asphalt Maintenance

For existing parking lots, proper asphalt maintenance is key to protect the structure from water damage. Here’s what you should tend to regularly to keep your lot in great condition:

  • Cracksealing. Cracks in your asphalt can allow water to penetrate below the surface and cause considerable damage. This is especially true in winter since water expands when it freezes. At Bituminous Roadways, we recommend cracksealing during the spring and summer months to maintain the quality, appearance, and structural integrity of your asphalt.
  • Sealcoating. Sealcoating helps maintain the appearance and structural integrity of your parking lot by protecting it from vehicle fluids, UV rays, rain, and snow. It fills in surface damage to prolong the life of your asphalt and improve its aesthetic appeal.
  • Patching. Asphalt is porous, so water from snow and ice can infiltrate below the surface during winter and cause minor cracks to form. Patching these cracks before they grow severe is an excellent way to maintain the integrity and performance of your parking lot.
  • Pothole repair. Winter weather is notorious for causing potholes in asphalt parking lots all over Minnesota. If you notice holes in your asphalt when the snow and ice melt, tending to pothole repairs promptly will help protect your parking lot from further moisture-related damage.

Encourage Efficient Subsurface Drainage

The materials that comprise the subsurface layer of your parking lot will either encourage or impede subsurface water drainage. A class 5 aggregate base will help water drain away from your parking lot quickly while providing considerable strength and stability. If that’s not enough to encourage efficient drainage, implementing a 12- to 18-inch sand layer beneath the aggregate will further improve drainability.

Drainage tile, also referred to as a French Drain or underdrain, is another option for encouraging efficient subsurface drainage. This drainage solution involves building a subsurface channel below the pavement that features a perforated pipe connected to a stormwater pipe or catch basin. Geofabric, round river gravel, and perforations in the pipe function to filter incoming water, and the pipe then disperses that water away from the asphalt.

Need to Fix Drainage Problems With Your Parking Lot? Contact Bituminous Roadways

Whether your existing parking lot is having drainage problems or you’re looking to create a new parking lot that drains water efficiently, get in touch with our team at Bituminous Roadways. For over 75 years, we’ve proudly served commercial and industrial properties throughout the Twin Cities metro, and our asphalt paving solutions are second to none.

To get started or learn more about how we can help you, give us a call today at (651) 686-7001 or request a free estimate and consultation here.