How to Build Deck Stairs

If you have a deck area that has been elevated to a decent height in the area. You will definitely need a staircase section that can take you up and down from the area. While there may be a lot of intricacies involved, by thoroughly going through the necessary procedures, you can take the time and make the effort to construct a proper flight of stairs leading up to your deck area.

Tools required

  • Circular saw and hand saw
  • Tape measure
  • Sandpaper
  • Level
  • Plumb

Materials required are

  • Plywood (pressure treated)
  • Concrete
  • Masonry anchors
  • Deck Screws (galvanized)


  1. Analyze your deck area and have an idea of how your stairs will fit in and what section of the deck it will be installed to lead to. Try and design the stairs so that it can hold more than one person at a time. Make a plan that will have all the measurements. To do this you will have to calculate the number of steps, the height, length, and width of the stairs.
  2. Start by finding the total rise of the staircase, which is the total height of all the stairs together, and the tread which is the width of each step of the stair. We calculate the total rise by measuring the distance from the ground to the base of the deck, it will lead to. Then divide the figure you get by 7½ (7.5) this will represent the number of steps the stair will have. More likely the figure will be a decimal, so round off the number to the greater whole number.
  3. Next, we need to find out the average rise of the stairs, which is the height of each individual step. To calculate this you will have to divide the total rise of the stairs by the number of stairs. The same rule applies in regard to the result being a decimal. Find the length of the staircase by multiplying the number of steps by the depth of the staircase (known as the tread).
  4. With all this information you will now be able to have a clear understanding of where each segment of the staircase will go be placed. Mark the location where the stairs should leave the ground and where it should enter the deck section.
  5. Clear the area at the base where the staircase will start and remove all the unwanted objects then dig up the area about 6 inches deep. Make sure the area is leveled off and mix a batch of gravel, concrete mix, and water with a shovel to make your mortar. Pour it into the foundation area until it covers that area then use a trowel and a level to smooth off and level the area then allow the concrete to set and dry.
  6. Now cut out all the pieces that will be needed to make the staircase for the deck. First, we cut the stringer which is the side of the staircase steps. For this article, we will use 2*12 boards. Measure and mark off the sections of the stringer with a framing square, using the measurements from the average riser (height of the step) and the tread (width of the step). Start from the top corner of the board and mark off and cut out the pieces with a circular saw. Use the hand saw to cut out the pieces at the corners. One less riser will be needed because the first step of the stairs will start from the ground.
  7. Place the bottom end of the stringer onto the concrete base and the top end onto the face of the deck and attach them using the deck screws (3 inches). Use a plumb and a level to secure that they are placed properly.
  8. Use the circular saw again to cut out a 2*6 board to connect the stairs to the concrete base using masonry anchors. Then fasten the board between the two stringers at the base with more deck screws.
  9. The next step is to cut out the stair tread pieces. Use 2*6 board pieces and the circular saw to cut them out. Make the stair tread so it overlaps the stringer by about 1 inch. Start from the base of the stairs and attach the tread board against the back of the stringer, make sure it is centered and when installing ¼ inch of space should be left between the first and second tread piece then use deck screws to attach each side. Repeat this process until you reach the top of the stairs.
  10. Now we will go into the details of making the railing for the deck stairs. For this, we will use a 4*4 wood stock for the posts for the lower section of the railing. We will have to notch out a piece of the first tread to install the posts for the railing so mark off this point using the posts and cut out the notch with the handsaw. Then use more deck screws to connect the railing post.
  11. Now we will use a 2*4 board to cut out the railing section that will connect the top of the lower posts to the top of the upper posts on the deck, and then connect it with deck screws. Cut out more pieces for the lower railing and the balusters. Then install the lower railing exactly parallel to the upper railing.
  12. Join the balusters between the upper and lower rail supports so that it runs parallel to the main railing posts with approximately 3 – 6 inches of gap between each.

Tips and Warning

  • Make a conscious effort to always purchase the best wood for the deck stairs, preferably the same that was used for the deck area. The wood should be firm with no damage and getting advice from a specialist is always a good idea.
  • While you are cutting and assembling all the sections of the stairs, you should always check with the plans to make sure the measurements match that on paper.
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