Attaching wood stairs to a concrete or stucco wall can crack the stucco and cause the coating to break if it is not attached correctly. Follow these steps to easily wood stairs to a concrete or stucco wall with a few tools.
Step 1 - Measure the Steps and Ledger
You need to create a flat surface on the wall first. If the wall has a heavily textured surface, scrape or sand it down lightly without damaging the stucco. Measure the side or end of the steps that will be attached to the wall in order to gauge how long the piece of hardwood board ledger must be. The ledger will be attached to the wall, then the stair to the ledger. Attaching in this manner provides a wide area of attachment, putting less pressure on small areas of the stucco.
Step 2 - Cut the Ledger to Size
Cut the ledger to size. If the steps are going directly into a doorway, make the ledger 6-inches wider than the door frame, or as wide as the steps, whichever is the wider. Remember to angle the ends of the steps to the ledger for a neat finish. Use an angle measure to do so.
Step 3 - Drill Holes in the Ledger
Drill the holes down the center of the ledger board 12-inches apart. The holes should be big enough for the bolts to fit. Get your helper to hold the board in place on the wall and poke your pencil through the holes to mark where the bolts will be placed in the wall. If the stairs are large or heavy, double the holes, one row above the other, every 12-inches. If you have wood or drywall behind the stucco, you must mark and drill into the wall studs.
Step 4 - Build Supports
If the steps are being attached to the wall along one side, you must install posts to support the other side. Place a support post at the top of the steps. If they are long, do so every 4-feet until you reach the bottom. Cut the tops of the posts to fit. Even if the stairs are light and you have attached them well to the wall, if they are not supported on the non-wall side, there will be enough movement to pull at the stucco and damage it.
Step 5 - Drill the Wall
Drill the holes into the walls at the marks. If you are using lag bolts, drill into the basement or wall space. Line up the board with the holes and screw in the bolts. For solid walls, use expansion anchors.
If your wall is made of hollow concrete blocks, you will need to fill the spaces with grout before using expansion anchor bolts. These hollow blocks are not strong enough to hold stairs. Without the grout, they will loosen, which will damage the stucco.
Make sure the steps are firmly attached to the wall. Any movement will damage the stucco. If you are worried about the stucco, you can build separate supports for the steps so they do not actually touch the wall at any point.