How to Pour a Concrete Overlay On An Existing Concrete Driveway or Other Flatwork

Most concrete contractors, including myself avoid pouring concrete under 4 inches 
thick over an existing concrete surface. Concrete is normally poured monolithically, 
meaning all at once and almost never under 4 inches. Although customers ask 
concrete contractors to avoid the costs of concrete removal by just pouring concrete 
over an existing concrete structure, we almost always avoid it. Reason being is 
because we know if there are any existing concrete cracks in the existing 
concrete surface, they will almost always continue through the new concrete 
overlay. However, there is a little known way to successfully achieve this 
which will enable a concrete contractor to offer their customers more options.

The ground always settles and concrete structures crack or lower with the ground. 
Sometimes the concrete lowers so much where the concrete begins to slope 
towards the house, instead of away from it. This can cause erosion problems to 
the foundation of the home because water is always supposed to be designed to 
drain away from the house. When concrete is falling at an angle a 
concrete contractor avoids making a concrete overlay because although you 
may be able to pour 4 inches of concrete on one side of the driveway, it may 
only be a few inches thick in other parts of the driveway. I had a customer that 
had such a problem and the customer was pleased with the concrete overlay 
because it solved their drainage problems during torrential rains.

One of the main reasons concrete cracks after pouring a concrete overlay is 
because the concrete moves. Armed with safety glasses we took sledge hammers 
and pry bars and made dimples over the existing concrete to help limit this problem. 
Then we took a jack hammer and made holes in the existing concrete and dug down 
into the soil about two feet deep. We made five holes in the shape of a five on a dice, 
two on each side and one in the middle. We kept these holes at least 
4-5 feet away from the edge of the existing concrete so we didn't weaken or crack 
the substructure. These holes became concrete pillars when we poured the concrete 
reinforcing the strength of the concrete preventing it from moving to prevent cracking. 

We reinforced the area where the automobiles met the concrete with impact 
by digging a six to eight inch footing instead of just four inches. We had to saw 
cut the existing driveway to do this and we ensured the first two feet of the 
impact area of the driveway was 6-8 inches deep. This also helped alleviate 
the chance of the concrete moving and cracking. I believe we may have also 
used fiber mesh concrete which is stronger. The customer was satisfied and 
even voluntarily sent me a complimentary letter.

No concrete contractor can ever guarantee their concrete will not crack  
Although a concrete overlay should still be avoided to ensure happy customers, 
there are times when this technique can be used successfully to offer the customer 
more options. 

Dale B. Adams formed Majestic Publishers in 2000, and is the author and self publisher of the new book, “Care Giving Made Easy – How to be an Awesome Caregiver” Second Edition and the soon to be released, “How to Make Your Home Sell – Even In A Slow Market” His many experiences include being a Security Consultant, General Contractor and Energy Conservation Specialist. To learn more valuable information visit: http://www.majesticpublishers.com.