Installing carpet on stairs is a great way to tie in a carpeted floor to a tile or hardwood floor. If you have bare stairs they can seem dull and are often looked over but with carpet they can seem warm and inviting especially if they are visible from you front entrance way. We recommend that you do not carpet the entire stair but instead leave a small strip of wood showing on each side of the step. When wood and the carpet are properly matched it can make for an exquisite stair case.
Before we get started let us explain the materials and parts of the stairs to you so you are not confused later on during your installation. There are two parts to a staircase the tread and the riser. The tread is the part you step on and the riser is the vertical piece that supports the tread. The materials you will be using are: tack strips, Carpet padding and a carpet runner. The tack strips are thin strips of plywood with same nails sticking out of the tops of them. These will be nailed onto the riser next to the tread to prevent the carpet from shifting. The carpet padding is a lining that goes underneath the carpet to give it more support and to add cushioning to make the carpet feel soft on your feet. The carpet runner is the strip of carpet that will run the length of your stairs and give the finished look.
First start by measuring the length of your stairs, measure the tread and the risers all the way down. Then add one inch to your measurement for each stair to make sure you have a little bit of extra to work with. It is always better to have too much carpet than not enough. If your measurement is in inches you will need to convert it to yards so take your total measurement and divide it by thirty six. You will need to buy the same length of carpet and carpet padding. Depending on what you have decided buy carpet to fit the entire width of your stairs or you can take off about three inches on each side so a little bit of you stairs will show and in most cases this is a much more appealing choice.
Before you start any work on your stairs go over them and scrap up any bumps or lose material that is on your stairs and give them a good vacuum. Now cut your tack strips to be about two inches shorter than the total width of your carpet so that they will not stick out from underneath your runner. Next nail the strips in the corner where your tread and riser meet, on both the tread and the riser, making sure they are centered to the width of your stair. The strips must have the nails pointing into the corner or the runner will not be able to be pulled tight when installing later. When you nail the strip to the riser you will want it to have a three quarter inch gap between it and the tread, you can use a three quarter inch piece of scrap to help hold it up for you. You need to have the same size gap for the strip you install on the tread as well. Repeat this process for each stair.
Now you will install the carpet padding. You will want to have your padding only about a quarter inch shorter than the width of your carpet runner so it will fit neatly underneath. Measure from the edge of the tack strip to the lip of your tread, add about three inches so you will be able to wrap it around and under the tread. Then using a utility knife cut your piece of padding. Center the pad on your tread and push it tight to the edge of your strip and using a nailer place some nails next to the strip. Now pull the padding tight and wrap it over the end of your tread and nail the padding to the underside of the tread with about three inch gaps between nails. Continue this for each stair.
It is now time to install your carpet runner. Check the bottom end of the runner to make sure the end is square. If it is not, use a framing square and a utility knife to cut it straight. If you do have to cut the end apply some carpet glue to the cut seam the keep the carpet from fraying. Start at the bottom of the stairs roll the carpet up a few steps so it is out of your way. Making sure your runner is tight to the floor begin nailing it on to the riser, again with approximately three inch gaps between nails. Next pull the carpet tight to the underside of you tread and nail it in place. Making sure your runner is still in the center of you stair, pull it up and on top of your first tread. You will need a knee kicker for this next part. A knee kicker is a tool used to push the runner tightly over the tack strips so they hold it firmly in place and a lot tighter than doing it by hand.
Push the runner into the corner of the tread and riser and then place the knee kicker about two inches away from the tack strip and use your knee to pound the end of the kicker. This should push the runner over the strips and hold it firmly in place. Start at one side of the runner and work along the step until the whole runner is taut. Finish the step by using a carpet tool and a rubber mallet to pound the runner into the corner of the step between the two strips (see picture below). If you do not have a carpet tool. you can use an awl instead. Continue the process on every riser and tread making sure that the runner is still in the center of the stair.
When you get to the top of the stairs if there is a lip that you can tightly fit your carpet up to simply nail the carpet at the top of the riser and make a clean cut and take off any of the excess carpet you have left. If you do not have a lip you can use a stair cap that will cover up the edge of your top stair.