A double application of chip seal is a very cost effective method to upgrade a gravel road. The first layer is applied to the prepared sub-grade, compacted, and allowed to cure overnight, then swept off the next morning. A second layer is then applied with the same procedure. The finished product is 7/8” to 1” thick. Special consideration may be required for steep grades. Traffic can drive on it at any point in the construction process.
Proper preparation is critical for longevity. Prepare the existing sub-grade first; ditch, grade, crown and compact the road beforehand, including grading the shoulders, if necessary, so water flows off the road. Then spread one and onehalf inches (average depth), of 5/8" minus crushed rock and compact. More rock may be needed, depending on the condition of the existing sub-grade at the time. The finished sub-grade should be compacted firm & tight, with a uniform crushed rock surface. Moisture content is critical for proper compaction, 95% compaction needed. Weed killer may be needed under the double chip seal if sod or roots have been graded over the roadway.
The recommended time frame for chip seal maintenance (re-coating with an additional layer of chip seal), to keep the road in good condition, is 8 to 10 years. However, for the first re-coating, we recommend re-coat within 2 to 5 years. The reason is that the first double chip seal is relatively thin. A third layer within a few years gives it the thickness & body to last to the next 10 year maintenance cycle.
When comparing your options, a good exercise would be to make a 15 year comparison: Double chip seal, with a third layer after 5 years, compared to hot mix asphalt paving, (after 15 years, both types of surfacing would need another layer.) The chip seal becomes cost effective in quantities over 3,500 square yards
Also make a 15 year comparison to gravel roads: Double chip seal, with a third layer after 5 years, compared to gravel road maintenance (grading every year, adding fresh gravel, pothole maintenance, dust control, & additional wear & tear on your cars)
Please contact us to receive a price quote for your situation.