http://www.homebuildingandrepairs.com/repairs/stair/index.html Click on this link for more videos and information about stair building, repairs and new home construction. Sometimes the exterior would stair stringer will need to be replaced, but for those situations where the damage is minimal, you might be able to use the information in this video to make the necessary repairs. The most important suggestion I could make with this repair would be to make sure the stairway is securely braced and supported to where it will not move at all if you will be cutting or removing any part of the stringer.

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