My husband and I are getting ready to build a new home. We are worried about all the digging that will happen at the site. What should we be concerned about? How do we know that the hole will be correct in both size and depth? What happens if the excavator runs into water? I’m filled with anxiety that there will be problems. Will my house lot look like a wasteland for years because of the heavy machinery? — Amber D., Plano, Tex.
I can understand your apprehension. Backhoes, excavators and track loaders with toothed buckets are not too far removed from dinosaurs. A giant gash in your lot where trees and bushes used to be can absolutely shake you to your core.
The good news is that, with a little water, sunshine and a great landscaper, at the end of the project your lot and the new home will look fantastic. Don’t be too concerned; just try to look at other completed homes that have finished landscaping and imagine that’s where you’ll be soon enough.
That being said, your excavator can make some mistakes. In my opinion, the worst one would be digging the hole too deep. All too often, I see houses where the top of the foundation is just inches away from the ground or grade level around the home.
The building code has strict guidelines for how high the foundation must protrude above the ground and how much slope there needs to be to the ground falling away from the house. The top of the foundation should be at least 14 inches above the highest point within 10 feet of the house line.
Keep in mind that you need to have the ground slope away from the house on every side. Where a house is built into a hillside, you have to create a drainage swale on the uphill side of the house. This usually means constructing some sort of retaining wall uphill from the house to create this drainage feature.
When building houses, I always took precise measurements with my builder’s transit and drew a picture showing how deep the basement hole should be. I didn’t guess. I was there constantly monitoring the depth of the hole.
You also need to be concerned about reaching good soil. Some lots are comprised of fill dirt, and some have buried vegetation. I’ll never forget acting as a consultant in a lawsuit about a home that was built directly on top of an old streambed into which the developer bulldozed trees and then covered with soil. The house eventually started to crack in half as the vegetation rotted and the soil dropped.
A good builder and excavation contractor can almost immediately spot fill dirt. If you have access to old topographic maps of your area, you can often see the old valleys that got filled in by developers.
If you do run into the water table and your lot has a slope to it, you can dig a trench leading from the hole in the ground until the trench daylights. The ground water will drain naturally through this trench. A pipe can be installed in the trench and connected to a foundation drain system around the house so this water permanently has a pathway to the surface.
If you have a nice wooded lot and want to preserve the trees, you need to make sure the construction equipment doesn’t drive over the soil under and near the trees. This may mean creating just one pathway for ingress and egress to the basement hole. It’s well worth the money to hire a certified arborist to develop a plan to protect the trees. In almost all cases, you have to erect sturdy fencing to keep all construction traffic away from the trees.
Tim Carter is a columnist for Tribune Media Services. He can be contacted through his Web site, askthebuilder.com.