How to Brace Pressure Treated Stairs

Adding a Stringer

• 1

  Access the space under your pressure-treated stairway by clearing away paneling or lattice work if necessary. Measure the rise and run, or height and depth, of each step along the stairway with a framing square. Make your measurements between the existing stringers, or notched lumber that support the individual pressure-treated stairs.

• 2

  Transfer your measurements to a pressure-treated 2x12 with a pencil. Account for all irregularities within the stairway and include a line to designate the level of the ground where the stairway's current stringers rest.

• 3

  Cut out the form of the new stringer by laying your 2x12 across two sawhorses and cutting along your pencil lines with a circular saw. Cut along the line that indicates the level of the ground as well.

• 4

  Place the stringer under the pressure-treated stairway at the site where you took measurements. Screw it into place by driving deck screws through the lumber diagonally and into the treads and risers with an electric screwdriver or drill.

Installing Brackets

• 5

  Access the space beneath your pressure-treated stairs and locate any problem areas. Check for gaps, treads that flex when stepped on, or treads and risers that are beginning to pull away from stringers, revealing the nails or screws that hold them in place.

• 6

  Install galvanized steel angle brackets wherever there are 90-degree angles between pieces of pressure-treated wood that have weakened. Use deck screws and an electric screwdriver or drill, screwing through all of the holes that are predrilled on the brackets.

• 7

  Install galvanized steel seismic ties using the same process as angle brackets. Screw them in wherever there is a solid section of the stairway that is perpendicular to, but not abutting, a weak point.

  For example, galvanized steel seismic ties can be used to attach the bottom of a riser to the face of a stringer if there is not enough space for an angle bracket.