Build & Install a Picture Post
by John Pickle
by John Pickle
Consider purchasing a plastic lumber post top - it will last for many years with no maintenance! The plastic top can be drilled just like wood, or attached to an existing structure. Click here for purchasing information.
Materials (Cost ~ $20-$30)
- 7 to 8 foot 4" x 4" post (consider pressure-treated lumber or plastic composite lumber)
- 9-inch diameter plywood disc, 3/4" thick
- 5-inch plywood octagon (2-inch sides) 3/8" to 1/2" thick
- Permanent marker or paint with fine tipped brush
- Four 3" to 3.5" coarse thread exterior drywall screws
- Glue (exterior quality)
- Polyurethane (exterior quality)
- Portable drill and 1/8" drill bit
- Shovel or post-hole digger
- GPS (Global Positioning Satellite device)
Step 1: Build the Post Head
Step 2: Placing the Post
- Choose a location best suited for your interests (e.g. your garden, wooded area, meadow, favorite tree, pond, etc.).
- Consider accessibility by others.
- If public, make laminated instructions to post.
Step 3: Installing the Post
- Dig a hole at least 3 feet deep and wide enough for the 4x4 post. You want 4 feet of the post above ground.
- For stability, the bottom of the post must be below Frost Depth. For the Boston, MA area, this is 3 feet. Talk to local builders to see what is recommended in your area.
- You may attach post head to an existing post or secure structure.
- Keep the post vertical, back fill the hole with dirt, tamp dirt until firm and post is stable.
Step 4: Assembling the Post
- Center and level post head (from Step 1) onto post.
- Take and record the GPS reading from the top of the post to find the latitude and longitude.
Step 5: Aligning the Post Top to True North
- Find True North for your location.
For Boston, MA area in early 2006, magnetic north is 15 degrees west of true north (see photograph of compass). Notice that the compass is held so that the white tip of the compass, which points north, points 15 degrees west of north.
- Align an edge of the 5" octagon east/west with respect to true north
Step 6: Securing the Post
- Double check alignments and drill four holes through the post head into the post.
- Secure with the drywall screws.
- Using permanent marker or paint, label the post head with location information and basic instructions (see photograph in lower right).
- Seal with polyurethane.