Deck stairs withstand the punishment of the elements, so installing carpet on those deck stairs needs to be done properly for it to stay in place. Use carpet rated specifically for outdoor use only. This kind of carpet is not only able to put up with the elements, it is also durable enough to assist in the installation. Take your time on this installation as you will not get many chances to fix any errors. You will be using methods and materials that will create a permanent carpet installation on your deck stairs, so plan this out well in advance.
Step 1 - Preparation
Installing carpet on deck stairs does not create any kind of surface for mold to grow, so when you prepare your steps for installation all you are doing is making a clear surface to work with. Any debris caught under the steps could cause bumps that would look unattractive and make the steps uncomfortable to use.
Sweep the surface of each stair with a stiff bristled broom. Then use a garden hose with a nozzle on it to create a strong water stream and use it to clean the stairs thoroughly. Allow the stairs to dry before installing the carpet.
Step 2 - Starting with the Top Step
Lay the carpet on the top step and press down on the carpet to form it to the step. Use a staple gun with weather resistant staples to staple the carpet in place. Staple as close to the edge of the step as you can on each side.
Step 3 - Working Your Way Down the Steps
When you move down to the next step make sure you are pulling the carpet tight to make it fit to the stairs. Staple the carpet down to the next step in the same manner as you did the first step. Be careful not to injure yourself with the staple gun.
As you work the carpet into place on each step, be sure to hold it as you staple. If you let the carpet get away from you, then you will start to get wrinkles in the carpet and it will be uneven. Work the carpet all the way down all of the steps until you get to the last step.
Step 4 - Cut to Form
Use a utility knife to cut the carpet to size on the stairs. Leave some carpet at the bottom to finish the job. Cut the carpet as close to the edge of each step as possible. If the steps do not have any kind of frame along the side then wrap the carpet around the edge of each step before cutting it. If there is a frame along the edge of the steps then cut the carpet so that it is flush with the wooden frame.
Step 5 - Securing the Rug
Install a row of staples down the middle of each step to help secure the rug and prevent it from slipping when people walk on it.
Test the rug once you have stapled it to make sure it is not moving. If the rug moves, continue to staple it until it is secure.