Costly rentals or equipment—you might want to leave this one to a pro.
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What you'll need:
TOOLS
Bull float
Edging tool
Garden sprayer
Hammer
Level
Magnesium float
Metal-cutting blade
Plate compactor
Safety glasses
String
Tape measure
Wood saw
SUPPLIES
1/2-inch diameter rebar
6-mil plastic sheeting
Concrete
Curling compound
Duplex nails
Foam insulation
Forming lumber
Packable gravel fill
Tie wire
Wooden stakes
Wooden kickers
A foundation provides a stable and level base to support the weight your home, make it a critical step in the construction process. If you're taking on the mighty task of building a house and are ready to start, read on to learn how to build a foundation.
Preparing To Build a Foundation
Building a foundation is not a project with a quick turnaround. Before you embark on this expert-level DIY, know that the project will take about one month to complete, usually between three and six weeks.
Before you begin any work, hire a local land surveyor to help you determine your property lines and how close you're cleared to build in proximity to them. The surveyor will mark the boundaries and layout of the foundation on the ground based on architectural plans and local regulations. From there, you must obtain building permits, which should be done well before any work. The last thing you want is to be told you need to make costly changes after work has begun.
Ahead of time, you must decide which foundation type you want to build and the depth you want. Planning this ensures you have enough supplies to complete the job.
Completing this project will not be a one-person job. It will require professional assistance and, at the very least, extra labor to help pour the concrete. Prepare to call in some favors from friends and neighbors.
Prepare the Site
Eliminate any trees, bushes, vegetation, stumps, sizeable stones, or any remains from former construction in the area. Set the slab plot parallel to the border and hammer wooden stakes into the soil to show the boundaries of the spot. Use a tape measure to double-check the dimensions to ensure accuracy.
To prepare the site, you may need to know how to build up soil around the home’s foundation to allow water to drain properly. Otherwise, water could pool and cause damage to the integrity of the structure.
Dig a trench into untouched soil of sufficient bearing capacity. The depth of the excavation should match the needs of the foundation type, taking into account any frost lines for colder regions. Maintain a uniform depth to prevent soft spots or an unstable surface. This step will require the assistance of a professional excavator unless you already own the equipment and are skilled at completing this type of project.
Pack the soil firmly by running a plate compactor over it, digging a 12-inch wide by 12-inch deep trench at the edge to provide extra thickness to the slab's edges. Place plastic sheeting on top of the fill.
Build the Frame:
To strengthen and prevent cracking, install steel reinforcement bars (rebar) in the footings and along the foundation walls. You will need to know how to square a foundation. Start by positioning metal stakes around the perimeter of the wooden forms, about 4 inches in. Cut the rebar, bend it, and splice the lengths together using tie wire to create two rebar perimeters, with one atop the other.
Lay a rebar grid on the plastic sheeting, spacing them 4 feet apart and running the length and width of the site, and then connect the intersections with tie wire.
In locations with a great deal of rainfall, homeowners must take steps to better prepare the grounds surrounding the foundation. This will aid in warding off water damage, one of the leading causes of home repairs, and guard against moisture from seeping in from below the foundation. Taking the time to craft the landscape for optimal water flow around your house can drastically reduce the impacts of flooding.
Plan for the delivery of concrete on a day when the weather is not too extreme, such as heat, wind, or rainfall. Verify that your forms are balanced and aligned with appropriate support. Ensure the forms keep the concrete securely contained, reaching all corners and edges, and are evenly distributed.
You'll need to enlist a few trustworthy friends or laborers who know how to pour a foundation to assist with the pouring process. You don't want to skimp out on help because it can be costly to repair if the job doesn't go right—foundation repair costs range between $2,161 and $7,788, but can be even higher if the initial build isn't done correctly.
A straight 2-by-4 screed board is the perfect tool to level the concrete in a process known as screeding. Double-check that the board is straight by using a string line for accuracy. As you pull the screed board, have a partner or contractor add or remove concrete in front of the board as needed.
Afterward, a bull float can be pushed across the screeded concrete to further flatten it, with the leading edge slightly higher. Up to three or four passes can be made across the surface, though any excess water should evaporate before an edging tool is used to round off the slab edges and give them a smooth finish.
You can begin finishing the surface once the concrete has dried enough to bear your weight. Situating yourself atop foam insulation squares, utilize a magnesium float to smooth out any irregularities from edging and leveling. You may need to put a bit of force into the float if the concrete is hardening too quickly. To give a perfectly smooth finish, hand float it, followed by troweling with a steel trowel.
Cure the Concrete
The process of curing the concrete should be started the day after the pour and repeated two or three times daily. Without sufficient curing, cracks can quickly appear, and the durability of the structure's components will be impacted. This practice is vital for providing enough moisture for the chemical reaction that contributes to the strength of the concrete.
Spray the surface of the foundation with a curing compound using a garden sprayer as directed on the product's label. After the curing process is over, you can carefully remove the forms.
DIY vs. Hiring a Pro
Building a foundation is not a project that can be completed independently. Even if you choose to forgo hiring a professional foundation contractor, you will need extra sets of hands to tackle the job, plus other necessary contractors to help with various steps.
A home's foundation is the primary support for the structure and must be done correctly. Any errors could be costly to fix and result in a great deal of damage to the structure. Your best bet when building a home is to hire a local foundation expert.
Frequently Asked Questions
Slabs are typically the most budget-friendly option for a foundation. Because they don't require building excess space for the home, less material and excavation are required. Eliminating these cost factors will impact the overall budget. If you don't need a basement or crawl space, opting for a concrete slab will suit your home's support just fine.
No, it is not recommended to pour your own foundation. Aside from being time-consuming, the labor of pouring foundation is more than just a one-person job. Assistance from multiple people is required to ensure the concrete is poured accurately. While you may be able to complete this step with friends, hiring contractors for support is best.
Concrete should not be poured directly over grass, as this will impede the necessary tension of the concrete. Grass and soil can draw in moisture, leading to potential cracking. For a solid, lasting foundation, the area must be flat, firm, and completely dry.
