FOUNDATIONS FOR NEW GARAGES
August, 2008

Most of the garages in Cleveland Heights were built much differently than were the homes--and certainly not with the same level of quality. Many were erected right on the ground, with no foundation at all to support them. Often the floor (concrete or asphalt) was added after the structure was completed. Over the years, many of these garages with no foundations (or with foundations that are inadequate) have seen the bottom third of their walls and structural framework rot out due to ground dampness and snow accumulation. Moreover, the action of the wind pushing against the structure and the repeated freezing and thawing of the ground may have caused the weakened garage to move, with the result that the garage can end up leaning this way or that.

If you are replacing your old garage with a new one, you can avoid such deterioration by installing a good foundation. There are two common types, either of which will satisfy City code requirements. The first type is best, but it does cost more. In this method, a footer is poured first, and then a short wall is added above it, molded from concrete or built from concrete block. The wall, built around the perimeter of the structure, is 6” to 8” wide and extends from 8” above the ground to at least 36” below the soil, or “grade” (so that it goes below the frost line). This perimeter wall is allowed to cure, and then a separate concrete floor, 4” thick, is poured inside it. After the floor has set, the garage walls are built upon and bolted to the foundation wall. This is the strongest design, one that is similar to the way homes are built.

The other type of garage foundation is a monolithic slab (meaning “one piece”) of concrete, poured all at one time. The floor area is 4” deep before it thickens into a short wall formed around the perimeter, 6” wide and 8” above grade and 12” below. The garage framing is then bolted to this perimeter wall as it is erected. The disadvantage to this system is that all the stresses placed on the walls and roof (from soil heaving with the freeze-and-thaw cycle, tree roots. rain, wind, and heavy snow) are transferred to the floor, making it prone to cracking. Because the foundation is shallower, you are also more likely to have burrowing animals, such as skunks, make their home under your garage.

If you are considering a new garage, you should be aware that most contractors' bids are based on the second type of foundation, because it is less costly. Although the first method is more expensive, it can be well worth that additional cost. Not only will the frame last longer and stay straighter, but it is also far less likely that you’ll have to replace your garage floor due to cracking--a project which would cost much more than the additional money you'd spend for the first type of foundation.

It's never easy to decide to spend more money, but a new garage is a long-term investment. When making your choice, look to the future and consider the benefits of a good foundation. The extra money you spend might turn out to be a bargain five or ten years from now.

In addition to this month's tip, you can check out previous articles from Project Repair. And, we'll be back next month with another repair tip...