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If you're passionate about DIY projects and enjoy enhancing your home, you've likely considered undertaking a small construction project. One of the most critical aspects of this endeavor is laying the foundation. There are several simple steps to ensure your foundation stands strong over time. With some hard work, patience, and attention to detail, you'll have your foundation poured in no time.
Steps
Preparing Footings for Your Foundation
Determine the depth of your foundation. Typically, foundations are about 3 feet deep (0.9m) into the soil. However, various factors must be considered. For instance, if you're excavating in high-moisture soil or on a hillside, you may need to dig deeper.
- There's a simple method to test soil moisture. Use an empty coffee can, leaving three inches of space at the top, and fill it with water. Time how fast the water soaks in. If it's slower than 1 inch per hour, the soil has very low moisture levels.
- While home methods can help, consulting a professional is advisable. They can conduct diagnostics tests to assess soil conditions, measure soil flatness, and determine if any adjustments to the foundation's height are necessary.
Develop a comprehensive plan for your foundation.
Clear the area surrounding your foundation. Remove grass, roots, and any debris nearby. Utilize the property survey to determine foundation height. If the site isn't level, use a backhoe or shovel to even it out.
Contact 811. Prior to excavation, dial 811 (Digline) to request utility companies mark underground pipes or wires. This prevents accidental damage, ensuring project safety. Call several days before digging commences.
Excavate your foundation with a backhoe. While a shovel works, it's slower and less precise. The footing hole should exceed the foundation size by at least 2 feet on all sides. This extra space facilitates footing installation.
- The perimeter hole should ideally be 2 feet wide and 2-3 feet deep.
- Remember, you're only digging around the building perimeter, not the entire building area. Clear any excess dirt and debris after excavation.
Place rebar for the footings. Proper support is crucial for concrete durability. Purchase rebar suitable for your planned footings. Attach grade pins to lift the rebar, available at most hardware stores.
- First, set the rebar and then position the grade pins atop, spacing them 2 feet apart and 1 foot from corners.
- Lift the rebar and secure it to the grade pins using the manual hooks provided. Avoid using ties or strings, which can damage the footing.
- Ensure the rebar is equidistant from the base and sides of the opening.
Pour the initial layer of concrete.
Smooth the concrete surface using a hand float. Ensure no cracks or crevices remain, providing a smooth base for later construction. Once dry, use a level to confirm evenness.
Constructing Foundation Walls
Prepare wooden frames for the walls. Each board, approximately 2 feet by 10 feet and an inch or two thick, will form the foundation walls. Place the shorter sides of the boards atop the initial concrete layer, ensuring no gaps between boards.
- Add dirt around the outer boards to stabilize them.
- Use metal bars outside the frames to secure the boards tightly.
- Alternatively, use plywood strips across joints and duplex nails to hold the boards together. Ensure sturdy staking to prevent board displacement during concrete pouring.
Prepare and pour the foundation walls. Ensure the correct concrete mixture and form the entire structure at once, preferably with a concrete truck. The amount of exposed wall above ground level depends on your building's resting level.
Secure old foundations to the new one by pinning them. Drill 3-4 holes about 6 inches apart on each side and insert pins into them.
- Pinning is crucial to prevent wall shifting and potential building collapse.
- Pour the second and third walls adjoining the initial one, allowing the concrete to join them over the pins.
- Reinsert pins into the sides of the subsequent walls.
Smooth the tops of the concrete walls. Use a hand float to ensure no cracks or crevices exist. Additionally, use an edger to smooth the edges.
Take off the wooden frames. Once the concrete has dried, remove the frames promptly to avoid sticking. Pull them up from the top to prevent damage to the newly poured walls.
Apply a waterproof coat to your foundation walls. Purchase spray-on waterproofing from hardware stores to add an extra layer of protection against water damage. Make sure to coat both sides of the walls.
Foundation Pouring Process
Spread gravel, sand, and/or crushed rocks over your foundation area. Use a rake to distribute the material evenly between the newly poured walls. Ensure it forms a layer no thicker than 1 inch.
- If using gravel for foundation fill and slab pouring, layer it 6 to 8 inches deep. Compact with a plate compactor in various directions until well settled. Add another 6 to 8-inch layer (lift) and repeat compaction until 4 to 6 inches from the top of the wall.
Place a polyethylene sheet on top of the gravel layer. This serves as a vapor barrier, preventing moisture from seeping into the foundation and causing cracks. Opt for a custom-sized sheet matching your foundation dimensions.
Install wire mesh and rebar over the vapor barrier. Follow local building codes for specifications. Wire mesh reinforces the concrete, reducing the risk of cracking.
- Add bar chairs to support the wire mesh, inserting them directly into the plastic sheeting at intervals of two to three inches.
Integrate radiant floor heating and drainage pipes. Position drainage pipes along the outer edges of the foundation to prevent water buildup beneath the structure. Install radiant floor heating if required, directly above the polyethylene sheet.
Mix and pour the foundation concrete. Ensure the concrete consistency is correct. How to Make Concrete Use a bull float to smooth the surface, then an edger for the edges. For minor inconsistencies, wait for slight drying, then use a hand float atop foam to refine details.
Embed anchor bolts into the concrete before it sets. These can be purchased from your local hardware store. Anchor bolts are crucial as they secure the building to the foundation slab. Position them with about half protruding from the concrete, spaced one foot apart and one foot from the corners.
Allow 7 days for curing before construction begins. No waiting is necessary for the foundation to settle into the ground, as construction should occur on undisturbed soil.
Helpful Tips
- Prioritize additional features like drainage or radiant heating before pouring a concrete foundation. These must be considered beforehand.
- Start with smaller projects such as laying a foundation for a shed or gazebo. Once you've mastered the basics, progress to larger, more complex undertakings like house foundations.
Warnings
- Seek guidance from licensed contractors or engineers if you encounter difficulties with any step. Proceeding uncertainly can lead to unintended building code violations or critical errors in your foundation construction.
- Uneven dispersion of sand or gravel on the foundation floor can result in cracking or irregularities in the concrete foundation. Ensure uniformity in height when spreading to avoid any significant variations.
Essential Supplies
- Rake
- Shovel
- Tape measure
- Concrete mix
- Water
- Crushed rocks, sand, or gravel
- Vapor barrier
- Wire mesh
- Rebar
- Foundation anchors
- Drill
- Hand float
- Bull float
