There are many other factors that could have contributed including insects, rodents such as ground hogs, weather, poor soil quality, etc.

We had a sprinkler system at a house that we though had been removed, but it turned out all the heads, etc were just buried under gras and soil due to disuse.

@Zach Sikes I'm technically north west in Cobb County but I'm open to working downtown, Cobb County, or Sandy Springs/Roswell areas

I'd put my money on the fact that they put the addition on spread footings without doing much to improve the soils under them. 

Large, transverse cracks are the larger worry, as they are more likely caused by differential settlement in your foundation (the soil underneath a portion of your foundation wall dropping, while the rest stays more or less where you want it - look for a "stair-step" pattern in your mortar joints), water trapping against (or worse, inside) the wall and expanding during the winter freeze cycles, or insufficient steel reinforcement - which is not uncommon with concrete masonry, particularly if the house is pre-1950s (ish). 

,Soil characteristics, vegetative cover, and status of mineral rights, andOther factors affecting value.For each comparable sale, the appraisal must include the names of the buyer and seller, the deed book and page number, the date of sale and selling price, a property description, the amount and terms of mortgages, property surveys, the assessed value, the tax rate, and the assessor's appraised FMV.The comparable selling prices must be adjusted to account for differences between the sale property and the donated property.

Sandy.

Ensure that you put the adequate sub base in place and rent a tapper/soil compacter, form the pavement area, order the concrete from your local concrete plant and place it yourself.

@Dennis M.Good ole Sandy Lake, PA?

Law Offices of Mike Florence in Sandy Springs