HOW TO INSTALL A McGREGOR DEER FENCE: CEMENT FOOTINGS
EARLY STEPS, CONTINUED
Video: Installing Cement Footings
In certain cases, some metal deer fence posts should be put in cement footings. Determining which ones need this requires a bit of common sense. In New England, where snow typically falls before the ground is fully frozen, the corner, end, and gate posts of all deer fences should be put in cement footings. Beyond that, there is always some risk that the combination of a heavy snow load and unfrozen ground will be able to tilt the fence posts enough to require major repairs or even replacement of the fence. To reduce this risk, do not allow heavy snow loads to remain on the fence, and also consider setting some of your line posts into cement footings--as many as every other line post on a metal hexagrid fence or every third line post on a polypropylene or welded wire fence. You do not need to put your corner posts in cement footings if these posts are not braced; but all the posts that are braced, or to which earth anchors are attached, should be placed in cement footings.
Note that if your fence never needs to deal with heavy, wet snow at a time when the ground is unfrozen, that relieves its ground-gripping parts of an immense potential weight burden. Similarly, if you are putting up light polypropylene fencing weighing say a tenth of a pound per foot, that requires less ground-gripping power than metal hexagrid fencing weighing about a pound per foot. And if you are putting up a short fence with no run longer than, say 40 feet, that also reduces the potential stress. So if you a protecting a small California vegetable garden with 40-foot sides using polypropylene deer fencing, you may reasonably decide to forego the joy of installing any cement footings.
To create a cement footing, start by digging a 10 to 12-inch diameter hole with an auger or manual post-hole digger. This hole should be below the frost line if there is deep winter ground frost, and 2 feet deep if frost is not a problem. If the hole is, say, 3 feet deep, fill the bottom 12 inches with large rocks (softball to hardball size), place the post in the hole, and measure to ensure that the top is 7 feet above the ground, adding or removing rocks as necessary to obtain the proper height. If the hole is 2 feet deep follow the same procedure without initially placing rocks but adding rocks if necessary.