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A snow fence is a lightweight fence, usually plastic or wood, with holes or slats covering much of its surface. The ideal snow fence is 40 to 50% porous, meaning these openings cover about half the surface area. A fence with a much lower or greater porosity will be much less effective.  Each hole or slat is usually 2 to 2.5 inches (5–6 cm) wide. Openings wider than 6 inches (15 cm) are not effective.  Before buying a fence, read on to learn about truss-type and sheet fencing. This is a series of wooden panels supported by a rigid framework. Truss-type fences are cheaper to install and easier to remove (for temporary fences), but take up more space and are less effective on slopes. There are several different designs for this type of fence, so refer to the manufacturer's instructions if possible. Here's a common example of what this installation might look like:  Drive rebar posts into the ground at a 30–45º angle. These posts can typically be shorter and more widely spaced compared to the standard set up described below.  Set the framework against these rebar posts. Set the panels at a 15º angle to the ground over the framework. Overlap the panels. The other main type of snow fence comes in rolls of sheeting or slats, to be strung across standard fence posts. This is the best choice for slopes, and for areas with limited horizontal distances available. Keep reading for detailed instructions on this type of fence. You can spray paint the ground, or secure a line of brightly colored string to keep the fence to a straight line. Although the fence is light, these are load-bearing posts that must stand up to the weight of a snowdrift. First, add 10 to 15% of the fencing height to allow for a gap between the fence and ground. Next, choose posts that are tall enough to support this fence when 2/3 of the post is above ground.  For example, if your fencing is 4 ft (1.2 m) tall, the top of the fence will be 4 x 1.1 = 4.4 ft (1.3m) off the ground. Your posts should be 4.4 x (3/2) = 6.6 ft (2 m) tall.  Drive #5 rebar into the ground every couple of feet and weave it through the sheet of fencing. . Use a post hole digger to create holes deep enough to bury 1/3 of the post height. The taller the fence, and the stronger the wind is in your area, the closer the posts need to be to resist wind force. Consult local building codes for a recommendation, or follow these guidelines for a strong fence (withstanding winds up to 100 mph or 160 km/h):  Space steel T-posts 8 ft (2.4 m) apart to support a 4 ft (1.2m) tall fence. Space them about 4.5 ft (1.4 m) apart instead to support a 6 ft (1.8 m) tall fence. Wooden post spacing varies with type of wood and circumference. Consult a lumber store employee or a local handyman. If the ground has already frozen, digging will be much more difficult. You can thaw the ground by building smalls fires over the post hole locations, contained under vented metal containers. You can also rent ground-thawing equipment for large jobs. . Bury each post 1/3 of its height and secure it firmly. Pack in about 6 inches (15 cm) of soil at a time. Between each layer, tamp down the soil firmly and confirm the post is level.  A layer of pea gravel at the base of the hole will improve drainage. You may use concrete instead of soil. Leave a gap above the ground about 10–15% the fence height. Paradoxically, this gap lets the fence trap more snow. If the gap is too small, a deeper upwind snowdrift will partially bury the fence, making it less effective and potentially damaging it. Pull the fencing taut and secure it to the posts with cable ties. In high wind areas, reinforce this attachment by sandwiching the post between the metal post and a wooden slat before tying them together. Fasten ties about every six inches (15cm) along the height of each post. For even more security, slip foam insulation over the post, then sandwich the fencing between that and a wooden batten. Proper maintenance will help the fence to perform the best. Regularly check the anchoring system and look for missing or damaged parts that need to be repaired.

Summary:
Check the fence porosity. Consider a truss-type fence. Continue reading for sheet fencing. Mark the line where your fence will go. Calculate the height of the fence post. Dig the post holes Drive in the fence posts Plan to leave a bottom gap. Secure the slats to the posts. Maintain the fence.