Adding Stability to Posts/Pillars
Adding Stability to Posts/Pillars
Option 1: Adding Strength with a Concrete Pile & Sonotube
Mark the layout of the post
Prepare the foundation pad
Prepare hole for sonotube
Install the sonotube, level and brace
Fill sonotube with concrete to create the concrete pile
Install base material for post blocks
Install first course of the post
Build next course of the post, alternating the blocks to offset the vertical seams
Build post to desired height
Secure the blocks together with flexible concrete adhesive to add strenght to the post
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
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.
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
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.