Building taller posts

Adding Stability to Posts/Pillars

Adding Stability to Posts/Pillars    Print this Document

Download (.pdf) How-To Sheet #140

Option 1: Adding Strength with a Concrete Pile & Sonotube

Layout AB Courtyard Post/Pillar

Mark the layout of the post

Remove Sod and Dig to Correct Depth

Prepare the foundation pad

Dig Hole for Additional Reinforcement

Prepare hole for sonotube

Insert Concrete Form, Plumb and Brace

Install the sonotube, level and brace

Fill with Concrete and Insert Required Reinforcement

Fill sonotube with concrete to create the concrete pile

Prepare Post Base

Install base material for post blocks

Build Base Course

Install first course of the post

Continue Building Post/Pillar

Build next course of the post, alternating the blocks to offset the vertical seams

Finished Reinforced AB Courtyard Post/Pillar

Build post to desired height

Using Glue to Add Strength

Secure the blocks together with flexible concrete adhesive to add strenght to the post

AB Courtyard Reinforced Post/Pillar section

You Will Need:

  • 8 in. sonotube (200 mm), cut to desired length
  • Posthole digger
  • Ready mix concrete
  • Rebar (as required based on application)

Note For All Post/Pillar Construction:

The soil beneath the foundation pad must be a good quality compactable material. If soft soils are encountered, you will need to remove and replace them with additional base rock. A good foundation will ensure a stable post/pillar for years to come.

Step 1: Layout

Determine the location of the post/pillar and lay the first course of block to establish where to dig the foundation pad.

Step 2: Foundation

Mark the location of the post/pillar with a shovel, remove the blocks and dig a 24 in. (600 mm) square, 4 in. (100 mm) deep hole. Using a post hole digger, dig a hole for the sonotube approximately 3 ft (1.0 m) deep with a 8 in. (200 mm) diameter to accommodate for a 8 in. (200 mm) sonotube in the center of the foundation pad.

Step 3: Sonotube

AB Courtyard Reinforced Post/Pillar Section

Mark and horizontally cut the sonotube so that the tube will extend up within the top 3 courses of the post/pillar. Install bracing (if necessary) on the sonotube 12 in. (300 mm) from the bottom. Next place the sonotube in the post hole and install vertical bracing to hold the sonotube in a level upright position.

Step 4: Concrete Piles

Pour the concrete mixture into the top of the sonotube until both the sonotube and the post hole are filled. Make sure the sonotube is level and plumb. (Rebar can be added while concrete is wet, as required based on application). Allow concrete to set a minimum of 4 hours before proceeding. Once the concrete is set, remove the vertical and horizontal bracing on the sonotube.

AB Courtyard Reinforced Post/Pillar layout

Post Layout

Step 5: Foundation

Fill around the sonotube with 4 in. (100 mm) of base rock to build the post/pillar foundation. Use a hand tamper to compact. Level foundation pad from front to back and side to side, making adjustments where needed. A level foundation pad will ensure a level and plumb post/pillar.

Step 6: Base Course

AB Courtyard Corner Block

Corner Block

AB Courtyard Reinforced Post/Pillar

Install the first course with 4 Corner Blocks with the long sides facing out. Square up the blocks, tamp into place and level.

Step 7: Continue Building

Continue stacking courses, alternating between the patterns to offset the seams from the course below until the desired height is achieved. Do not stack the blocks up in stacked bond (seams should not create a straight line the full height of the post/pillar).

Step 8: Finish

Finish the post/pillar with two Post Caps. Secure the Wall Caps in place with a bead of flexible concrete adhesive along the outside edge of the top course of Corner Blocks and then set the Post Caps in place.

More Options: Building Posts/Pillars in Soils or
Adding Additional Stability

Use one of these three additional options when building in soft soil conditions. If building with posts/pillars and panels, interlock the panels into the posts/pillars for additional stability. See How-to sheet #230: Interlocking Walls and Posts.

Install Concrete Footing Below Post
Install Concrete Footing with Bell
Increase Base Depth and Width