Extending the top of a wooden privacy fence with lattice adds additional privacy while making your fence more attractive and decorative. The process is relatively straightforward: You must extend your existing posts and then add lattice to the top along the post extensions. In a simple project, you can add the lattice as is, but for a nicer, more finished appearance, first encase it in a wooden frame and then mount each framed panel along the top of the fence.
Cut the 4 by 4 posts to the lengths required for your extension. Your extension can be whatever height you choose, but a height between 1 and 2 feet will typically suffice.
Attach the post extensions to each of the existing fence posts using a metal tie plate and screws. Simply screw the plate to the post and to the extension. For added stability, you can use a layer of wood glue between the post and the extension.
Cut the lattice into sheets the right size (height) for your extension using a table saw.
Construct a frame for each piece/panel of lattice using the 2 by 2s. If you cannot find 2 by 2s, you may need to buy 2 by 6es and cut them into the appropriate size. To construct a frame, you'll use a router saw to cut a groove into one side of the 2 by 2. The lattice will fit into the groove. You'll also use the mitre saw to cut the corners for your frame so they meet along 45 degree angles.
Insert one side of the lattice into one edge of the frame at a time. Make sure all four sides of the frame will fit tightly around the lattice. Then sink screws into the corners of the frame to hold it together.
Paint, stain or finish the lattice panels as preferred.
Attach the panels along the top of the fence to the post extensions using more screws.
Be sure to wear all safety gear when working with saws. Sand your work after each cut to remove any splintering.