How to Cut Asphalt for Fence Posts
Sometimes, the fence you need to have installed runs over an existing parking area or roadway. This means that there’s a layer of asphalt (or tarmac if you’re not in North America!) that you will need to contend with.
Let’s take a closer look at how to cut asphalt for fence posts, dig holes without damaging the surface, and repair the surface after you’ve finished.
How Thick Is Asphalt Usually?
The layer of asphalt on a road or parking lot is usually about 25 millimeters or about an inch. Under that layer, there is usually a layer of six to eight inches of well-compacted road gravel. However, below that, you will usually have the natural soil that was there before the roadway was laid.
This is why you can’t bolt and baseplate a fence to an asphalt surface – there’s just not enough structure there to support it.
Mark Holes Carefully
Proper fence setting out is always important, but it’s even more crucial when you’re doing something like cutting through asphalt to place your fence posts.
Measure everything carefully and double-check everything to be absolutely certain your holes are marked in the right place. Mark the position of your holes carefully so that you can find the exact spots to cut and dig each post hole.
How to Cut Asphalt
The best way to get a nice clean hole in your asphalt is to use a grinder to cut all the way through the asphalt on all sides of the hole and then use a pick or other tools to break up the asphalt inside the cut hole.
This helps to ensure that you only break up the asphalt inside the cut edges, which means there’s less to repair when you’re done.
How Big Should Your Hole In the Asphalt Be?
The problem with asphalt is that once it’s been in place for a while, it becomes hard and brittle. This means that once you start digging your fence post holes, it’s very easy to catch the edge of your cut hole and break more off than you intended to.
This means it’s a good idea to cut your hole a couple of inches bigger than your fence post hole will be so that you have more room to maneuver while digging.
How Can You Dig Your Fence Post Holds?
Once you’ve cut and removed the asphalt layer from your fence post holes, you can use any method you normally use to dig the actual holes – whether that’s a shovel or an augur.
Since the dirt removed from these holes will include some gravel or sub-base, you will probably have to remove it from site rather than spreading it out on a garden bed or similar.
How to Repair Asphalt After Your Fence Posts Are Installed
After your fence posts are installed, you will probably need to repair the asphalt or tarmac surface around them.
You could pour concrete up to the bottom of the asphalt layer and then use cold tar or cold asphalt in bags to replace the layer, compacting it well to create a durable finish.
Another option is to fill the hole with concrete all the way to the top of the surrounding asphalt. Once the concrete is dry, you can also paint it with black or charcoal grey paint to match the surrounding surface.
