• In this video, This Old House general contractor Tom Silva shores up an old deck with new supports.

    Steps:
    1. Install temporary 2x4 posts beneath the outer deck beam.
    2. Cut free any diagonal bracing with a reciprocating saw.
    3. Pry out the nails securing the existing vertical posts to the deck frame. Pull out the old deck posts and discard.
    4. Set a metal post base on top of the concrete pier, then drill a ½-inch-diameter x 3-inch-deep hole down into the pier with a hammer-drill and carbide-tipped masonry bit.
    5. If there's a metal pin or rod protruding from the top of the concrete pier, cut it flush with a reciprocating saw.
    6. Secure the metal post base to the concrete pier with an expansion anchor. Tighten the anchor with an impact wrench.
    7. Cut a new post to fit between the post base and underside of the deck frame. Fasten the post with galvanized hanger nails. Install one post under each corner of the deck.
    8. Use metal hangers to attach existing lattice panels or rails to the new posts.
    9. Stretch a tight chalk line between the two corner posts. Position the line 16 inches down from the top of the deck beam.
    10. Measure down to the chalk line at a midpoint between the two corner posts. If the midpoint dimension is 16 inches, then you know the beam is straight.
    11. Cut and install a post between the two corner posts. If the beam sags down, cut a post long enough to raise and straighten out the beam.
    12. With the new posts securely fastened in place, remove the temporary 2x4 posts.
    13. Install 2x4 diagonal bracing between the posts and deck beam. Secure each brace with 3-inch decking screws.

    See Products and Services from This Video
    • Difficulty: Moderate
      Mid-level carpentry skills required
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      Tools List

      • hammer
        Hammer
      • reciprocating saw
        Reciprocating saw
      • cat's paw pry bar
        Pry bar, for pulling nails
      • hammer drill
        Hammer drill fitted with ½-inch-diameter masonry bit, used to bore anchor holes in concrete piers
      • impact wrench
        Impact wrench, for tightening expansion anchors
      • miter saw
        Miter saw
      • sledge hammer
        Small sledgehammer
      • impact driver
        Impact driver

      Shopping List

      2x4s, for making temporary posts

      Pressure-treated 4x4s, used as posts

      Pressure-treated 2x4s, to make diagonal braces

      Metal post base and expansion anchor, used to secure the post to the pier

      3-inch decking screws, used to attach diagonal bracing