How to Install Post Bases & Side Rim Joints

Preparation

• 1

  Drive in one stake in each corner of the area that will be covered by the deck, using a hammer. Measure between the stakes and adjust as needed to create the size of deck you want. Dig a hole where each stake is 24 inches deep and 10 to 12 inches across using a posthole digger. Position cast concrete post footings on the ground, if you will be using them.

• 2

  Cut 4-by-4-inch posts for each footing using a circular saw, just an inch or two longer than needed. Stand one post in each hole, or in the top of the footing blocks.

• 3

  Cut your rim joists from 2-by-8-inch lumber to fit the outside dimensions of your deck. Cut the long sides to the exact length of the deck and your short sides to the width of the deck, minus 3 inches.

• 4

  Drill two holes 1 1/2 inches in from each end of the width pieces, one 1 inch down from the top and one 1 inch up from the bottom. Do the same on the long pieces, 3 inches in from each end. Use a 1/4-inch bit.

Construction

• 5

  Fit the two width rim joists to your corner posts at each end, so that the ends of the joist are flush with the outside faces of the posts. Set the joist at the correct height with a tape measure. Use a level to adjust the joist as needed until the bubble is centered in the indicator.

• 6

  Drive one 3-inch lag bolt, 1/4 inch thick, through each hole in each joist into the face of the post to anchor them in place using an impact driver. Position the long side joists so that the ends of the joists are flush with the outside faces of the shorter end joists. Drive one lag bolt through each hole to anchor them in place.

• 7

  Fill the postholes with gravel up to 2 inches below grade, if you used postholes. Pack the remainder of the holes with soil and tamp it in firmly. Trim the tops of the posts off flush with the top edges of the joists with a reciprocating saw to complete the project.