The construction process for mounting a fence into a driveway is virtually identical to building a fence over soil. The difference is the method used to set the posts. Driveways are typically built from asphalt or concrete. Depending on which material the driveway is made from, there are two approaches. Mounting a fence into asphalt requires breaking a hole in the asphalt and setting the posts into soil with quick drying concrete. Mounting a fence into concrete requires drilling into the concrete and securing a galvanised bracket designed and engineered to support posts.
Measure and mark the location of where each 4-by-4 post will be mounted. Draw a string line to represent exactly where the fence will be positioned. Using a measuring tape and marking paint, measure and spray a mark along the string line where each 4-by-4 post will be mounted.
Break apart the asphalt with a small jackhammer at each marking. Make sure to break apart each opening in a circular shape 6- to -8 inches in diameter. Remove the broken pieces of asphalt.
Dig out a post hole 18- to 24-inches deep using post hole diggers.
Set the 4-by-4 posts. Mix each bag of concrete in a wheelbarrow with water from the water hose. Mix the concrete with a mason's hoe. Each 4-by-4 post must be set in each post hole before filling the hole with concrete. The 4-by-4 post must be perfectly vertical and barely touch the string line. Pour the concrete in the hole around the 4-by-4 post until the hole is full. Test and correct the post to make sure it is still perfectly vertical and barely touching the string line. Allow the concrete to dry 24-to-48 hours.
Attach the remaining fence materials to the posts to complete the fence.
Measure and mark the location where each post will be installed. Tie a string line that represents exactly where each face of the fence is positioned. Using a measuring tape and marking paint, measure and spray a mark at each location along the string where the post will be installed. This is where the galvanised brackets for the posts will be attached to the concrete.
Mark the concrete with a pencil where each bracket will be installed. Hold the bracket over the post location and trace around the outside and through the hole at the bottom. This is exactly where the bracket will be fastened to the concrete and where the hole will be drilled for the anchor screw.
Using a rotohammer and masonry drill bit slightly smaller than the anchor screw, drill a hole into the concrete 5 inches as previously marked for the anchor screw.
Slide a washer over the anchor screw and drill the anchor screw through the bracket into the drilled hole in the concrete.
Position the post with a level in the bracket so the post is perfectly vertical. Use an assistant as necessary. Fasten the post to the bracket by drilling SDS screws through each hole on each side of the bracket into the post. Repeat for each post.
Continue building the fence after all the posts are secured to the existing concrete.