How To Build Concrete Steps

Building concrete stairs or steps using a concrete form and concrete finishing tools.

how to build concrete steps

The keys to building concrete steps are taking time to have the proper set up of the forms and finishing of the concrete. This article describes how to build concrete steps that are 3 risers high or less.

Keep reading to learn how to build concrete steps.

brief how to

In this article, you will find information about:

  1. Figure Out The Size Of The Concrete Steps

  2. Prepare The Ground

  3. Install Flashing

  4. Build The Form Panels

  5. Set The Form Panels In Place

  6. Layout And Install The Steps On The Form

  7. Pour The Concrete Steps

  8. Finish The Top Of The Concrete Steps

  9. Finish The Faces Of The Concrete Steps

  10. Cure The Concrete

tools and materials

  • 1/2" Plywood to build a form with
  • 2x4x16' to reinforce the concrete form
  • Nails
  • 2x8 lumber for stair risers
  • Steel Stakes
  • Pencil
  • Framing Square
  • Level
  • 1/2" x24" rebar
  • Circular saw
  • Hammer Drill with 1/2" bit
  • Shovel
  • Magnesium Trowel
  • Edger Trowel

step 1 Figure Out The Size Of The Concrete Steps

When building concrete steps, or any steps, the first step is to figure out the floor to floor height and the length of the stairway. These dimensions are calculated by finding the floor to floor height and dividing it by the number of risers and adding up the up the lengths of the treads. Exterior concrete steps are most comfortable with a 12" tread and a riser height between 6 to 7 3/4" with 7 1/2" being the most desirable.

How To Figure Out The Riser Height:

  1. Measure the floor to floor height
  2. Divide the height by the number of risers. You want a riser height between 7 and 7 3/4" Change the riser number until you get close to the optimal 7 1/2" stair riser height.

How To Figure Out The Total Run Of The Stairs: If you are using the top landing as the last tread then there will be one less tread than there is risers. For a simple 3 riser set of concrete steps there will be 2 treads.

  1. Determine your tread length, (12" is very common for exterior concrete steps).
  2. Multiply the tread length by the number of treads, the answer is your total run.

Figure Out The Width Of The Stairs:

When you build concrete steps plan on making the steps at least 6" wider than the door it is in front of and may be wider if you desire. Code requires that they are at least 36" wide but they are more comfortable when they are wider than the doorway.

Landings: If you are pouring a concrete landing at the same time as building the concrete steps remember that the landing must stick out from the house 36" and be at least the width of the door. (09 IRC, 311.3). But it is generally best to make the landing and steps 6" wider on each side of the door.

Codes Relating To Building Concrete Steps: There are some basic code requirements relating to the tread depth and riser heights of stairs. Your local building department may enforce another code so check with them before building. The requirements that apply to building concrete steps in the 2009 IRC (International Residential Code) are as follows:

  • Minimum tread depth is 10" (09 IRC, 311.7.4.2)
  • Maximum riser height is 7 3/4" (09 IRC, 311.7.4.1)
  • No more than 3/8" variation between the tallest and shortest riser height and the shortest and largest tread run. (09 IRC, 311.7.4.1 & 2)
  • No nosing is required on concrete stairs if the tread is at least 11 inches (09 IRC, 311.7.4.3x1)
  • Grippable handrail required if there are 4 or more risers (09 IRC, 311.7.7)
  • Minimum tread width 36" (09 IRC, 311.7.1)

Stair Height Example: If you have a floor to floor distance of 22 1/2" inches then you will have 3 risers at 7 1/2 inches each. With 2 - 12" treads there will be a run of 24" (unless you put an angle on the face of the steps and then the total run will be less)

step 2 Prepare The Ground

After you figure out the floor to floor height and the run length of the steps you will next prepare the ground to hold the concrete. The dirt should be compacted very well. If the soil where the stairs are going to be poured has been dug up recently then you should rent a mechanical compactor and compact the soil. Concrete stairs are very heavy and will sink if the earth is not properly compacted and proper drainage is allowed away from the stair location, even then there are no guarantees when you build concrete steps so make sure you do everything you can to get the soil compacted properly, there is nothing worse than building concrete steps that sink and / or separate from the house. It is common to compact the soil and then put a pile of dirt or hay bale under the stairs to save on concrete and weight.

concrete steps compacted soil

step 3 Install Flashing

There is no image of this but if the stairs are being built up against wood then metal flashing should be installed from the door down to 2 inches below the top of the foundation. It should extend out from the sides of the stairs at least 2 inches past the edge of the concrete.

step 4 Build The Form Panels

Wood forms are what holds the sides of the steps when the concrete is poured. They are typically built out of 1/2" OSB (Oriented Strand Board ) and 2x4's. It is easier to build concrete steps using form panels than to use lumber stacked up.

  1. Make the wood panels at least a little longer and higher than the finished stairs will be.
  2. Frame the panels similar to a exterior wall with a perimeter board and then boards across the face of the panel at 16" on center.
  3. Use two nails on each end of each board, at each connection.

concrete steps form framing

step 5 Set The Panels In Place

The wood panel forms are a key component to building concrete steps. They will hold the heavy concrete while it sets. These are the steps to setting the form panels in place when you build concrete steps:

  1. Make sure the form is on flat compacted ground and is fully supported along its base.
  2. Use wood pieces to fill any gaps between the form and the foundation or porch.
  3. The form should be plumb, straight up and down, or the sides of the steps will be angled.

concrete steps form panels

step 6 Install Steel Reinforcing

To hold the concrete steps to the house you should always drill 1/2" holes into the concrete foundation and hammer in 1/2" rebar. Use the hammer drill with a 1/2" drill bit to drill holes 4" deep and about 8" apart along the wall. Make sure the holes are at least 4" from the outside edges of the stairs and landing.

concrete steps rebar

step 7 Layout And Install The Steps On The Form

Using the riser heights that you decided on in step 1 draw the stair riser and tread outlines on the inside of the form panels. These marks are used to install the stair risers and will be the level of the top of the concrete when it is poured.

concrete steps layout risers

Cut the riser boards to length and nail them to the form panels by driving nails from the outside of the panels into the ends of the riser boards. A 2x8 board is actually 7 1/4" in height and often works well for the riser board without needing to be cut. To get the riser height perfect you will need to rip a 2x10 board to the exact riser height. If the form panels are not long enough to fit in all the stair treads then you can extend the form using 2x10 boards as shown in the image below.

concrete steps wood form

step 8 Brace The Concrete Forms

When it comes to bracing concrete forms you can never have too much bracing. Concrete is very heavy and will blow out a form if the form has an area that is weak. If you are in doubt then add another stake or angled brace.

  • Use 2x4 boards placed at an angle to the sides of the panel. Go from the form panel down to the ground.
  • Install a steel stake into the ground where the angle brace meets the ground to hold it in place.
  • Install 2 nails into the 2x4 where it meets the form panel nailing it to the form panel.

Tip: Ask the concrete truck driver what they think, they have watched a lot of forms blow out and have an idea of what looks strong.

concrete steps braced form

step 9 Pour The Concrete Steps

After everything is set up you are now ready to pour the concrete. Make sure to keep a pile or bucket of concrete so you will have extra cream when you rub the faces of the risers, see step 10

  1. Form Oil: Spray the inside of the forms with form oil or diesel fuel so they will more easily release when it is time to take them off.
  2. Concrete Mix: Make sure the concrete is not too runny. Overly wet concrete will try to slump down and push up under the lower steps. If the concrete is too runny you can pour the lower step and wait a bit before pouring the higher steps.
  3. Screed Off The Steps. Screeding is done with the mag trowel because you will not be able to get a longer piece of wood between the form boards. Make sure to follow the lines that were drawn to mark the tops of the stair treads.

screed top concrete steps

concrete steps form filled

step 10 Finish The Top Of The Concrete Steps

When building concrete steps each part of the troweling process is done multiple times as the concrete cures to bring out the best finish. As the concrete hardens the tools are able to put a "tighter" finish on the surface.

  1. 1st Mag Trowel: Use the magnesium trowel the first time to smooth the rough surface of the concrete from screeding it. On the first pass with the mag trowel you will see imperfections in the surface, these will smooth out on the next pass.
  2. 1st Edge: Use the edger to clean the concrete edges up and make sure that you are at the height of your surface lines on the form panels. Use the edge of the edger to scrape the cream off the top of the form boards and put it onto the edge of the concrete. Cream is necessary to get a good edge with the edger.
  3. Wait A Little Bit.
  4. 2nd Edge: This time use the edger first because it leaves a line on the surface that you will clean up next. If you need to you can scrape cream off the surface of the step and put it onto the edge.
  5. 2nd Mag Trowel: Use the mag trowel to smooth the surface again. Bring a little more cream to the surface to smooth out any bumps.

First edging.

concrete steps edging

First Edging

concrete steps edging

First Trowel

Second Edging

concrete steps second edge

Second Trowel

concrete steps second trowel

step 11 Finish The Faces Of The Concrete Steps

After the concrete is set up enough you will remove the stair riser boards. DO NOT REMOVE THE FORM PANELS! These are the steps to finish the faces of concrete steps:

  1. Remove the nails holding the two ends of each riser.
  2. Use a hammer to tap the face of the riser board and loosen it from the face of the step. Slowly slide the board upward, parallel to the face of the riser. Watch to make sure large pieces of concrete do not come with the board. If large pieces of concrete come away with the board then you need to wait a little longer. Small stone sized pieces of concrete may come off but they can be rubbed out using cream from the concrete.

This image shows removing a form board from the face of a porch cap but the process is the same.

concrete steps remove riser board

Use the mag trowel to rub the face of the riser. It helps to use concrete cream that you saved when pouring the steps. There will be pock marks on the face. Put cream on the mag trowel and rub it into the holes and imperfections.

concrete steps rub riser face

Use the edger to clean up the edges again.

Broom the surface: Use a concrete broom to put the final finish on the concrete steps:

  1. Dip the broom tip into water.
  2. Lightly pull the broom across the surface of the concrete to produce your desired finish.

step 12 Cure The Concrete

After the concrete has set up for 24 hours you are ready to cure it. This is a often overlooked step but will produce a much stronger set of stairs.

  1. Remove the form board panels by taking off all the bracing and lifting the panels parallel to the concrete surface while tapping on the back of the form with a hammer. Any imperfections in the concrete may be patched later.
  2. Lightly spray the surface of the concrete steps with water until there are puddles on top of the concrete.
  3. Cover the concrete steps with plastic so the water cannot evaporate.
  4. Let it sit for 7 or more days.
  5. Do not walk on the steps for at least a week.

Enjoy your new steps!

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