CHOOSE AND PUT IN A FOUNDATION FOR YOUR FENCE

Fencing in the backyard enhances both your privacy and safety. Although fairly straightforward, fencing must be done properly. A fence can be put up in five different ways: posts can be set in spikes, piles, concrete footings or form tubes, or sunk directly into the ground. The choice of foundation depends on the area, soil conditions, fence model, and, of course your budget.

This project details each completion stage for the five types of foundation and specifies the ideal soil and ground conditions for each type.

TOOLS

  • Post-hole auger
  • Gloves
  • Hammer
  • Sledgehammer

  • Screwdriver
  • Carpenter’s level
  • Line level
  • Tape measure

MATERIALS

  • Posts
  • Gravel, 0-¾
  • Stone dust
  • Concrete mix

  • Form tube (sonotube)
  • Metal spikes
  • Piles
BEFORE ASSEMBLY
NOTES

Municipalities have regulations and bylaws that govern the installation of fences and hedges, and it is up to you to be aware of any regulations that might apply.

Before you undertake a fencing project, locate the precise boundary of your property, lay out an installation plan, then measure the total length.

Make sure there are no pipes or electric cables in the ground where you’ll be working.

The installation of a fence can be accomplished in four ways: posts can be set in metal spikes, piles or form tubes, or driven directly into the ground.

Digging can be done with an excavator or an auger. It is simpler and less physically demanding to work with an auger.

Before inserting wood posts into the ground, apply a wood preservative to protect against rot.

The shorter the distance between posts, the more solid your fence structure will be.

STEPS
This is the most common method; it is simple and provides a sound foundation for a fence on regular terrain. It consists of digging a hole in the soil, inserting a post and then filling the hole with concrete or stone dust.

1. Determine the location

1.1. Put in stakes and run a string around the perimeter of the proposed fence; you can also use spray paint.

1.2. Mark locations for the 4" × 4" treated-wood posts. Spacing, centre to centre, may be at 4', 6' or 8' intervals depending on the size of the fence panels.

1.3. Use a posthole auger to dig holes 8" to 10" in diameter and 3' 6" to 4' deep for optimum stability and to prevent the posts from loosening when frost occurs.

2. Set the foundation

2.1. Lay a bed of 0-¾ crushed stone 6" deep at the bottom of every hole.

2.2. Apply a wood preservative to the section of the posts that will be below-ground.

2.3. Insert a post, then holding it upright, use a carpenter’s level to make sure it’s vertically level.

2.4. Put concrete or stone dust around the post to stabilize it.

2.5. Maintain the post in a vertical position, then use a level to make sure it’s plumb.

2.6. Posts may be higher than the desired height; you can trim them when the fence installation is complete.

2.7. Fill the cavity with stone dust up to ground level and water lightly to compact the stone dust. Ask someone to help you. Note that you may also use pre-mixed concrete: put the concrete mix and water
into the portable mixer, close the lid and mix for approximately 30 seconds. When it’s ready, pour the concrete into the holes.

2.8. Always verify your measurements between postholes before proceeding to the next posthole foundation.

2.9. Make the concrete mound-shaped around the post, an inch above ground-level; water will drain from around the post, keeping it dry.

POSTS SUNK DIRECTLY INTO THE GROUND
Using form tubes for posthole foundations is the most time-intensive method, and also the sturdiest. The fence can be secured solidly to the ground. It can be installed on uneven terrain and can withstand heavy winds. Both wood and metal posts are suitable.

1. Determine the location

1.1. Put in stakes and run a string around the perimeter of the proposed fence; you can also use spray paint.

1.2. Mark locations for the 4" × 4" treated-wood posts. Spacing, centre to centre, may be at 4', 6' or 8' intervals depending on the size of the fence panels.

1.3. Use a posthole auger to dig holes 8" to 10" in diameter and 3' 6" to 4' deep for optimum stability and to prevent the posts from loosening when frost occurs.

2. Set the foundation

2.1. Lay a bed of 0-¾ crushed stone 6" deep at the bottom of every hole.

2.2. Insert the form tube (sonotube).

2.3. Secure the tube by screwing it to an outer frame.

2.4. Make sure the distance between form tube centres is indeed 4', 6' or 8', depending on the size of the fence panels.

2.5. Insert the post and steel reinforcing bar into the tube.

2.6. Pour the premixed concrete and water into the portable mixer.

2.7. Close the lid tightly and mix for 30 seconds.

2.8. When the concrete is ready, pour it into the tubes.

2.9. Maintain the post in a vertical position, then use a post level or carpenter’s level to check that it’s plumb.

2.10. Make the concrete mound-shaped around the post; water will drain from around the post, keeping it dry.

2.11. Fill the cavity around the tube with stone dust, one inch above ground level.

2.12. Lightly water the surface in order to compact the stone dust.

2.13. Posts may be higher than the desired height; you can trim them when the fence installation is complete.

POSTS INSERTED INTO FORM TUBES (SONOTUBES)
Installing posts into footings set in concrete is a very secure method. It also means that replacing wood posts that may have rotted over time is relatively simple. Once the form tube has been filled with concrete, the footings are placed on the still-malleable concrete. Different models are available. This method provides very solid and stable results, and it’s suitable for a sloping terrain. Footings are ideal for 4" x 4" or 6" x 6" posts.

1. Determine the location

1.1. Put in stakes and run a string around the perimeter of the proposed fence; you can also use spray paint.

1.2. Mark locations for the 4" × 4" treated-wood posts. Spacing, centre to centre, may be at 4', 6' or 8' intervals depending on the size of the fence panels.

1.3. Use a posthole auger to dig holes 8" to 10" in diameter and 3' 6" to 4' deep for optimum stability and to prevent the posts from loosening when frost occurs.

2. Set the foundation

2.1. Lay a bed of 0-¾ crushed stone 6" deep at the bottom of every hole.

2.2. Insert the form tube (sonotube).

2.3. Secure the tube by screwing it to an outer frame.

2.4. Make sure the distance between form tube centres is indeed 4', 6' or 8', depending on the size of the fence panels.

2.5. Pour the pre-mixed concrete and water into the portable mixer.

2.6. Close the lid tightly and mix for 30 seconds.

2.7. When the concrete is ready, pour it into the tubes.

2.8. Place the footing on the surface.

2.9. Use a carpenter’s level to make sure the footing is level.

2.10. Make the concrete mound-shaped around the post footing; water will drain from around the post, keeping it dry.

2.11. Fill the cavity around the tube with stone dust, one inch above the ground.

2.12. Lightly water the surface to compact the stone dust.

2.13. Posts may be higher than the desired height; you can trim them when the fence installation is complete.

POSTS SET IN CONCRETE FOOTINGS (FOUNDATION SOCKETS)
If the ground where you want to install your fence is flat, in an urban environment, or sheltered from severe weather conditions and you want to put up a fence quickly, metal spikes are a good solution. This method is not recommended if the subsoil is clay or if the ground dries out during the summer (the ground will shrink away from the spike and become loose).

1. Determine the location

1.1. Put in stakes and run a string around the perimeter of the proposed fence; you can also use spray paint.

1.2. Mark locations for the spikes. Spacing may be at 4', 6' or 8' intervals depending on the size of the fence panels.

2. Drive the metal spikes into the ground

2.1. Fit a piece of sawn off wood post in the socket to avoid damaging the rim of the socket when you drive the spike into the ground.

2.2. Drive the spike into the ground until the base of the socket is level with the ground. Use a sledgehammer.

2.3. Check regularly that the spike is going in vertically and square with the run of the future fence.

2.4. Realign the spike in the ground if it begins to twist out of line.

2.5. If you are unable to set the spike support accurately, lever it out and try again.

Fence post foundation with metal spikes2.6. Repeat previous steps, and drive the spike into the ground again with a sledgehammer.

POSTS INSERTED INTO METAL SPIKES WITH SOCKETS
These post sockets are literally screwed into the ground. They are easy to install, but soft ground is a requirement. This method is not recommended for a sloping terrain or in areas exposed to a lot of wind.

1. Determine the location

1.1. Put in stakes and run a string around the perimeter of the proposed fence; you can also use spray paint.

1.2. Mark the locations where the anchor piles will be screwed into the ground. Spacing, centre to centre, may be at 4', 6' or 8' intervals depending on the size of the fence panels.

2. Screw the anchor piles into the ground

2.1. Use a screwdriver to screw the anchor piles in the ground.

2.2. Check regularly that the pile is going in vertically, level and
aligned with the run of the future fence.

2.3. Realign the anchor pile if it starts to twist out of line.

2.4. If you are unable to set the pile accurately, remove it and start again.

2.5. Screw the pile in again with a screwdriver.

POSTS INSERTED INTO ANCHOR PILES