I’m writing this article to explain what you should expect when your foundation gets poured on your custom home. At First Choice Custom Homes, we feel that the foundation of your home is one of the most important parts of your home, and if you start with a bad foundation, your project will be a fight from that point on. Therefore, we refuse to use any foundation company that is not the best around. Following is an explanation of what the process looks like.
We start the process by figuring out what the slope of your lot is which helps us to make sure water is draining properly around the house. This helps us determine how deep to dig out for the foundation as well. If there is a lot of fall on the lot, we may have to step the dig in order to limit the amount of concrete that we must pour. In order to keep the foundation company happy, when we dig, we try to make sure the ground is as flat as possible when done. This ensures that the thickness of your footings is as consistent as possible.
For a crawl space foundation, there is an 18-inch-wide footing that is 8 to 12 inches thick. It has 2 pieces of ½” rebar running through the middle of it that sit on rebar chairs, which keep the rebar in the middle of the footing instead of sinking to the bottom while the concrete is curing. In the middle of the building envelope, there are pier footings that are poured on a 7’ grid, with additional pads that are poured with specific load points in mind. After the footings have cured, the foundation company sets up their “short wall” forms which are made of either Wood or aluminum. There is one piece of ½” rebar running horizontally every 12” inside of the wall and a piece ½” vertical rebar running every 3 feet up to within 8” of the top of the wall. The height of a crawl space wall for a typical custom home is 29 inches on top of the footing and 6 inches thick. The foundation company will use 12” sonotubes on top of the pier pads and fill them with concrete as the supports for the beams that go under the floor joists of your custom home. The day after the walls are poured, the foundation company will come out and remove the forms off the wall and break the exposed ties that help hold the forms together while the concrete is wet. Next, we will give the concrete several days to cure and then will fill the garage with gravel to get ready for flatwork and backfill the house. At this point we will also do the rough grade, which makes it easier to work on the house and we can make sure any water flows away from the house as it should. Finally, right before the framers start, we have pea gravel shot into the crawl space.
For a custom home with a basement, there are a few more steps, which are as follows. Just like the crawl space foundation, we start with a footing, and unless the basement wall is going to be 10 feet tall or taller, the specs are the same for the footing. If the basement walls are 10 feet tall or taller, then the basement walls and footing must be engineered in order to satisfy the municipality that we are building your new home in. After the footings are poured, the foundation guys will set up their basement forms. The specs for the rebar are the same as the crawlspace, ½” horizontal rebar every 12 inches and ½” vertical rebar every 3 feet. The height of the wall is typically either 96” or 108” depending on how tall you want the ceilings in the basement of your custom home and they will typically step down towards the back of house if the home walks out in order to save on concrete. we will then build the walls up with wood where the foundation wall steps down. The thickness of the concrete in basement walls is 8 inches instead of 6 to provide more strength. Just like crawl walls, the foundation company will come and remove forms the day after they pour, after this point is where there are a few more steps involved. Whenever we build a custom home with a basement, we install drain tile inside the basement walls and along the outside. Drain tile is a perforated black plastic pipe that allows any water that might find its way under the floor or down to the bottom of the footing outside to collect in the pipe and run harmlessly out the back or lowest point of the house and away with any other drainage. If needed, we will install a sump pit so water can be pumped out of the interior drain tile system and outside. We then cover the drain tile with gravel, add gravel in the basement to the top of the footing and fill the garage with gravel. Next, we have the basement walls waterproofed up to the level of the grade and while that is happening, our plumbers install the plumbing that is needed under the slab and cover it up with gravel once that is complete. We then pour the basement floors, and finally, backfill the home and give the home its rough grade. Because the walls are taller and to protect the integrity of the walls, we like to make sure that the basement floors are poured first, which keeps the dirt from pushing in on the wall from the outside, which could cause the bottom of the wall to move. Because we have high water tables in this area, we recommend that any basement house be a walkout, which makes it easy to “daylight” interior drain tile and make sump pump un-needed. When done well, your foundation will be the start to your custom home that will help make the whole project run smoothly.
By Ryan Green
First Choice Custom Homes