How To Make Steps With Concrete

This article will explain how to make concrete steps like a professional mason. Constructing concrete stairs involves building the formwork, mixing the concrete ingredients in the proper proportions (unless using a pre-packaged mix), pouring the concrete and allowing for the curing process to take effect. The installation of a short flight of exterior concrete stairs beginning at the finished first floor and extending down to the grade level will be used as an example.

Tools and Materials Needed

• Wheelbarrow
• Portable cement mixer
• Shovel
• Form lumber
• Hammer
• Nails
• Premixed concrete or
• Concrete ingredients: Portland cement, sand, aggregate, water
• Trowel
• Screed board

Step 1 - Design the Stairs' Dimensions

The first step is determining the size of the stair components by obtaining the overall dimensions. A step consists of a riser (the vertical face) and a tread (the horizontal surface). A measurement is taken from the first floor level down to the grade and divided into risers of equal height, providing the riser height does not exceed local building codes. An overall vertical height of 30 inches would give 4 risers each at 7 ½ inches, a standard height found in many residences. The overall horizontal length of the stairs is more arbitrary; treads 11 inches or greater in width will give a comfortably sized step and are fairly common. The number of risers will determine the number of treads; the number of treads is always 1 less than the number of risers. 3 treads at 11 inches each will therefore give an overall horizontal length, or a total run of 33 inches.

The stairs will require a foundation, which is typically a slab poured to a depth of 6 inches below the grade level, with a perimeter equal to the footprint of the stairs (the total run by the total width of the stairs). 

Step 2 - Build the Form

Form-work can be built using plywood or structural framing members (2 x 4, 2 x 6 etc...) and is usually made from scrap or low-grade lumber. To begin, layout and cut the side forms according to the tread and riser calculations, so that they resemble a 2-dimensional side elevation of the stairs. The forms should be fastened tightly and securely to the building’s foundation so that the new stairs will bond to the foundation wall in a seamless connection. Wooden stakes are used as bracing to resist the outward thrust of the poured concrete and are nailed every 12 inches along the outer surface of the form. Install the boards that will form the face of the risers (they should have a width equal to the height of the riser) and add bracing to the center if needed. Use a level to ensure that the forms are plumb and the surface of the treads are level from side to side.

Step 3 - Mix the Concrete

The volume of concrete to be used is small enough so that mixing can be done manually. Concrete can be purchased as a pre-mixed, ready-to-use product that requires only adding water. If an alternate or specialized mix is preferred, the four basic ingredients, Portland cement, sand, aggregate and water, can be obtained separately. Water is added to the mix as needed (more will give a fluid, workable mix; less will result in a stronger concrete). A good rule of thumb when mixing concrete is to use 6 gallons of water per bag of cement.

Step 4 - Pour the Concrete

Start at the bottom step and pour one step at a time. Once the concrete is poured it should be spread evenly throughout the form, while spading or roding the mix to remove trapped air.

Step 5 - Finish the Concrete

Several finishing methods can be employed to achieve a smooth surface. A screed board worked front to back in a side to side motion will drag excess concrete from the treads.  A wooden float can be used to get an even, level surface. Hand-troweling will provide a finer finish.

The concrete should be kept wet or damp for up to a week after pouring and be protected from rain during the initial curing process. After this time the concrete has attained its final set and the form boards can be removed.