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How to Attach Stair Stringers to Headers

Attaching a stair stringer to a header is a very important part of the stair installation process. This is because the stringers carry the main load of the materials used for the stairs, as well as the weight of the individuals who use the stairs on a daily basis. After attaching a stair stringer to a header, a portion of the stringer will rest up against the header. One of the most common ways to attach a stair stringer to a header is to allow a full tread at the top of the stairs; this means that the tread will protrude one full step out from the finished floor at the top of the steps.

  1. Make marks on the header where the stair stringers will be installed. Use a speed square to make straight vertical lines so that the stringers are plumb when installed.

  2. Raise the first stringer once it has been cut to the proper size so that it rests against the header. If necessary, use an A-frame ladder to reach the top of the stringer.

  3. Place a stair tread on the top stringer to make sure the top surface of the tread is flush with the finished floor. The tread must be flush with the finished floor to prevent tripping.

  4. Hammer a nail into the top of the stringer at a slant so that it will penetrate both the stringer and the header, securing the stringer into place.

  5. Toe nail the sides of the stringer into place using 16d nails. Toe nailing is when the nail is hammered into the stringer at a slant so that it penetrates the stringer and then enters the header. Repeat the toe nailing at least five times on each side of the stringer to secure it into place. Repeat this process with any other stringers that may be used for the stairs.

  6. Slide a 2x4 ledger under the stringers so that the wide face of the board rests against the header. The thin edge of the 2x4 should be pressed firmly against the stringers.

  7. Nail the ledger to the header using 16d nails. The ledger is added to support the stringers in accommodating the combined weight of the stairs.