Driveway Sub Base: Why You Should Not Judge A Book By Its Cover

“Don’t judge a book by its cover.” Do you know that this saying doesn't only apply to an individual's personality? In building a concrete driveway, its exterior surface doesn't conclusively define its holistic character, quality and performance; such that, there are driveways that might have no customized logos, engravings or have less designs yet have firm foundation. Likewise, there are driveways with fantastic designs yet very prone to structural damages. Sub base is an important part of concrete driveway and it is on the top of the criteria for judging the performance and quality of your driveway.

A sub base is an interior layer above the subgrade of concrete driveway. The subgrade is the innermost layer underneath your driveway surface and the sub base is laid just above it. Sub base consists of aggregate materials and as a major load-bearing layer for concrete flatworks constructed for vehicular traffic, this is a necessary part. 

Sub base is vital for driveways because the concrete slab can support greater load if the sub base is compacted well and thicker. It also prevents water transporting from groundwater table up to the concrete sleep since it would trap water. Aggregates used to form the layer of sub base can be sand and gravel, or crushed concrete. The mixture of sand and gravel is compacted to interlock their granules and form a sturdy sub base layer. This layer created from these materials however is not that strong as compared to crushed concrete. This is because the granular size in sand and gravel mixture is uniform; as a result, there is less adhesion between the granules.

On the other hand, the granules of crushed concrete are not uniform in size. Crushed concrete is made up cement paste and crushed stones.  Gravel and sand can also be compacted with cement paste and crushed stones. This would produce a combination of large and fine granules that interlock effectively for a stronger driveway sub base

The minimum thickness of sub base for concrete driveways is 4 inches.  Vibratory drum rollers and vibratory plate rollers are used to compact the sub base materials. Drum rollers are preferred for driveways that would support heavy automobiles that require higher compaction density.

In hiring a contractor who will install your concrete driveway, find someone who knows how to apply the saying "Don't judge a book by its cover, '' meaning he will work on all the important parts of your driveway even those that are not seen like the sub base which is very important. All the parts should be given equal attention and quality so you won't just have a driveway beautiful on the surface but ugly in the inside due to a weak foundation.