Building Up: The Process of Making Concrete Stair Steps

Creating a durable and stable concrete staircase requires careful planning and execution. This guide will walk you through the entire process, from initial measurements to the final curing of the concrete, ensuring a solid and professional result.

Part 1: Planning and Safety

Before you begin, proper planning and safety precautions are non-negotiable.

• Determine Dimensions: Measure the total rise (vertical height) and total run (horizontal length) of your staircase. Divide the total rise by your desired individual riser height (typically 7-8 inches) to get the number of steps. Calculate the tread depth (typically 10-12 inches) based on the total run and number of steps.
• Essential Safety Gear:
  • Gloves and Boots: Concrete is caustic and can cause skin burns. Always wear waterproof gloves and boots.
  • Eye Protection: Protect your eyes from concrete splatter and dust.
  • Dust Mask/Respirator: Wear a mask, especially when mixing dry concrete, to avoid inhaling fine particles.

Part 2: Formwork Construction

The formwork is the mold that gives your stairs their shape. Building it correctly is the most critical part of the process.

1. Create the Stringers: Cut two side forms, known as stringers, from plywood or 2×12 lumber. Mark out the riser and tread dimensions you calculated, and cut out the profile of the steps.
2. Assemble the Forms: Attach the stringers to a backboard and stakes driven into the ground to create a sturdy, box-like structure.
3. Install Risers and Treads: Cut and attach wooden boards to form the front of each step (the riser) and the bottom (the tread). Ensure all corners are perfectly square and all surfaces are level. Use plenty of screws to make the formwork rigid.
4. Brace for Support: Add cross-braces to the formwork to prevent it from bowing outward when filled with the heavy concrete.

Part 3: Mixing and Pouring Concrete

With the formwork in place, it’s time to pour the concrete.

1. Mix the Concrete: Use a wheelbarrow or a mechanical mixer to combine the concrete mix with water according to the manufacturer’s instructions. The goal is a slump-free, workable consistency—like thick oatmeal—that is easy to spread but not too watery.
2. Pour the Concrete: Begin pouring the concrete at the bottom step, working your way up. Use a shovel or a hoe to pack the concrete into all the corners of the forms, ensuring there are no air pockets.
3. Vibrate the Mix: Use a trowel or a piece of rebar to gently “vibrate” the concrete. This helps it settle and eliminates trapped air bubbles, leading to a stronger, more uniform finish.

Part 4: Finishing and Curing

The final steps give your stairs their professional look and strength.

1. Screeding: Use a straight board to level the concrete on each tread, scraping off any excess mix to create a flat surface.
2. Troweling: After the concrete has begun to set and the surface water has evaporated, use a bullnose trowel to smooth the surface of each tread and round the edges of the steps for a clean, finished look.
3. Curing: Immediately after finishing, cover the steps with a plastic sheet or a special curing compound. Proper curing for at least 7 days is essential for the concrete to reach its full strength and prevent cracking. Do not remove the forms or put weight on the steps until the concrete is fully cured.