When you are building a residential garage or accessory structure, after the footing is dug and poured, the slab area is backfilled with sand. The fill is put at the level of where you want your garage slab to start. The reason for this is that sand is a wonderful agent to assist in drainage issues and will keep the ground under the slab free from water, ideally. Never use clay based products for backfilling. Clay holds water and drains poorly. This will make the ground beneath the slab move as the clay expands and contracts, which will potentially crack the concrete slab. Some locations for garages have a great deal of slope. Meaning, it is not level. That problem is also fixed by fill. Having large tree roots and balls can cause "craters" that can require hundreds of yards of fill and or topsoil to bring the area to grade. Residential building contractors cannot guesstimate yardage of fill. Each area has unique qualities and requirements. Talk to your builder before your garage project starts to clarify any questions you may have.
Call H.W. ENTERPRISES, INC. for your next building project. We are experts in erosion and settlement control and can properly address the topography of your property. Call 757-595-4562 for more information.