For very steep grades and severe flood conditions, super silt fence may be more effective than an ordinary silt fence. Super silt fence is a combination of chain link and synthetic mesh fencing, and it stands more than double the height of regular silt fence. Installation does not require any specialized tools or specialized experience.
Step 1: Layout the Fence Line and Posts
Install stakes at the corners of your super silt fence. Stretch out the string between the corners to establish a straight line. If the fence line is meant to curve, install additional stakes along the length to form the curve. Pull the string tight between the stakes, especially in windy conditions. If necessary, use additional stakes to keep the fence line where you want it to end.
Step 2: Dig a Trench
Dig a trench beneath the string line. The bottom third of a silt fence is always placed in the trench, folded so that the extra material lies flat on the ground facing towards where the water flow will come from. The trench should be 8 to 12 inches deep, and approximately 2 feet wide. Use paint to mark a dot beneath the string at 10 foot intervals. These marks are where your posts will go.
Step 3: Install the Posts
To install the stakes or posts for a heavy construction fence, use a sledgehammer. The guideline for setting a fence post is that 1/3 of the length should be below ground level. Keep in mind that the depth of your trench will make up some of the post depth when it is filled in. To save yourself some time, mark the posts with a pencil or marker, and then drive them in to the mark. This can save you a lot of time in checking and rechecking the depth of each post.
Step 4: Install the Fence
Install beginning at a corner and working in a consistent direction along the fence line. Attach silt fencing to the posts or stakes with roofing tacks and tabs. Tabs are typically round, flat pieces of thin metal that serve to increase the hold of roofing tacks, effectively extending the size of the tack head.
Step 5: Permanent Fencing
If the super silt fence is a permanent installation, you may need to dig post holes and fill concrete around the bottom of the posts. Unless you experience a problem with posts that fall over or are pushed down by the force of water, this step may not be required, but it will correct the problem if necessary.
A permanent silt fence is rare, but they are sometimes done installed the banks of streams to prevent their being contaminated by accidental spills or frequent flooding conditions.