Digging footings is a crucial step in the construction process, laying the foundation for any building project. This guide will walk you through the necessary preparations and considerations to ensure a successful footing installation before pouring concrete.
Before you begin digging footings, it is essential to ensure that you have the following in place:
- Building Permit: Confirm that you have obtained the necessary building permit for your project.
- Subgrade Preparation: Ensure that the pad is to subgrade and has passed proof rolling.
- Pre-Pour Meeting: Conduct a pre-pour meeting with all involved parties to discuss the project details.
Ordering Rebar
Ordering rebar is a critical step that should be done early. Here are some tips:
- Order Early: Ensure that the rebar is on-site when you are ready to dig.
- Order by Need: Only order the amount of rebar you need at the time to prevent loss or theft.
- Rebar Chairs: Decide whether to use concrete bricks or rebar chairs for supporting the rebar, and confirm with the inspector if necessary.
Concrete Ordering
When ordering concrete, always specify the mix design numbers. For example, if you require 4000 psi concrete, ensure you order it by the correct mix number to avoid receiving an unsuitable product.
Scheduling and Coordination
Proper scheduling is vital for a smooth operation:
- Footing Crew: Schedule the footing crew at least two weeks in advance to ensure their availability.
- Concrete Plant: Contact the concrete plant to get on their schedule about three days before the digging begins.
- Third-Party Inspection: Schedule a third-party inspection to ensure compliance with building codes.
- Pump Scheduling: If you plan to pump the footings, arrange for the pump in advance.
- Surveyor Coordination: Schedule a surveyor to lay out building corners or batter boards to assist the footing crew.
Weather Considerations
Start monitoring the weather a week before digging. Be prepared to make arrangements for concrete blankets if rain is forecasted, or consider rescheduling the crew if necessary.
On the day of digging, follow these steps:
- Inspector Coordination: Call your building inspector to confirm their arrival time.
- Verify Elevation: Double-check the bottom of the footing elevation before installing rebar to ensure it has been dug to the correct depth.
- Stockpile Spoils: After digging, stockpile the excavated material for later use or for the grader to haul away.
Dynamic Penetration Test
Before setting rebar, have a third-party conduct a Dynamic Cone Penetration (DCP) test to assess soil suitability. If the soil is too soft, you may need to perform undercutting, which should be documented on the unsuitable soils form.
Installing Rebar
Once the footing is confirmed to be suitable:
- Rebar Installation: Install the rebar according to the approved drawings, ensuring it is properly supported.
- Dowel Lines and Anchor Bolts: Lay out dowel lines and anchor bolts based on the surveyor's layout.
- Anchor Bolt Templates: Prepare anchor bolt templates in advance to avoid delays during the pour.
Concrete Pouring Preparation
Before pouring concrete:
- Check Access: Ensure there is adequate access for the concrete pump to avoid complications during the pour.
- Concrete Ticket Verification: Check the concrete delivery ticket to confirm the correct mix is being delivered.
- Third-Party Testing: Have your third-party inspector present to test the concrete and take cylinders for quality assurance.
Post-Pour Procedures
After pouring the footings:
- Cap Rebar: Cap any rebar that is protruding from the footings.
- Temperature Management: If temperatures are low, cover the footings with blankets to retain heat.
- Surveyor Follow-Up: Have the surveyor pin the footings the next day while the concrete is still green for easier adjustments.
- Documentation: Keep your forms updated to document the concrete strength and any issues with anchor bolts, as this is required for OSHA compliance.
Conclusion
Successfully digging footings requires careful planning, coordination, and adherence to building standards. By following these steps, you can ensure that your footing installation is efficient and compliant, setting a solid foundation for your construction project. With the right preparation and execution, you will be ready to move on to the next phase of your build: setting steel.
