An aluminum fence is fairly simple to install. The post holes only need be 6" diameter x 30-36" deep, so relatively small amount of concrete is required (gate posts should be 9-12" diameter). The panels are pre-assembled and posts are pre-routed for the rails. 

The fence can be "raked" 12" over a 72 1/2" section to run on slopes. Slopes greater than 12" over 6' must be "stair-stepped" to follow the slope. Since the line and corner posts are pre-routed with holes on two sides of the posts, the holes will be in the wrong place on one side for "stair-stepping". In this case end posts must be ordered instead of line posts, so the other side holes can be "field" cut in the appropriate place. The aluminum posts cut easily with most metal blade hole saws. Just install the post using one end that is pre-routed with that side on the high side panel and calculate the drop for the next panel and cut the holes in the appropriate places for the next "stair-stepped" panel.

The thumbnail above depicts a slope that is less than 12" drop over 6' and although the fence appears to be level to the rear, it actually falls uniformly with each section "raked" so the top stays straight and looks good. The sections could not be installed perfectly level because that would leave excessive space at the rear allowing the family pet to escape. This is a concept that many homeowners do not readily understand. You can have the fence close to the ground so "Fido" can't get out, or you can have it level. You can't have both unless each picket is longer than the last as the fence goes downhill. That is a difficult, custom installation that will cost you more in material and labor.

The photograph shows the residential style of aluminum that is not intended as a high security fence. The pickets, rails and posts are smaller sizes, both square and wall thickness, than the commercial grade in the same style. Also the near 4" spacing of the pickets and rail spacing may not meet local swimming pool codes. Another version has 1 1/2"-1 5/8" picket spacing for meeting building codes (styles 300+).

1. Locate the position of the posts to prepare for digging
The "opening size" of your gate is the distance between the inside of the gate posts. The gate finish size will be smaller to allow for the hinges and latch. Since the hinges and latch types may vary the space allowed for them will vary. The only measurement you can trust is what we call the "opening size". Use this measurement to space the two gate posts. Measure across your opening on the ground and mark the ground indicating the edge of each post. A 16' opening gate would have two marks 16' apart. Now to better visualize where the post must go, draw the post on the ground. A 6" sq. post would require that you draw a 6" square with the edge of the post on your opening size mark. See the sketch below.

2. Draw a circle around the gate post marks
The size of the circle, which represents the area to be excavated, should be larger than the post to allow for the proper amount of concrete. Multiply the diameter of the post at its widest point (diagonal on a square) by three and draw a circle with the post as the center using that calculation. If you are going to drill with an auger, simply mark the center of the drawn post marks to indicate the center of your auger. Now you have located the position of the holes to be dug.

3. Dig the holes
Dig the holes straight down to a depth of 36" minimum to 48" maximum. The depth required depends on the frost line depth in your area and the size of the gate. The depth of the hole is critical in avoiding leaning posts and sagging gates. Use the 48" depth for wide gates over 96" wide or heavy gates over 100 lbs. A 42" depth works for nearly any gate in most areas. If you are not sure, dig deeper. You only have to dig the holes one time--if you do it right. On small diameter holes, 6"-9", you could be limited to a depth of 36", because you can't get tools into the hole to clean it out. That is fine, if you followed the guidelines set forth thus far. The post will be shorter than the depth of the hole, i.e. 36" deep hole with 24" of the post in it. This is not unusual since the post does not need to extend the full depth of the hole. A common error is to assume the hole only needs to extend the length of the post. Make the shape of the hole so that the diameter at the bottom of the hole is wider than the top diameter. This we call "belling" since it resembles the shape of a bell. This will anchor the post and help to avoid post heaving due to frost. See below sketch. Under no circumstances should your hole resemble a carrot shape where the top of the hole is larger in diameter than the bottom.

Raking and Stair Stepping Panels

When the grade of the property follows a slope a decision must be made on the method of installation. It will affect the type of posts that need to be ordered, if they are pre-routed to accept rails.

A line post has pre-routed holes on two sides opposite each other and the holes line up with each other so panels can be installed level to each other. On level ground this is fine. If panels are to be "raked", these posts will work also. "Raking" is shifting the panel out of square as in the following illustration.

There is a limit that some panels can be raked. With ornamental aluminum the limit is 12" over a 6' wide panel in most cases. Certain styles may rake more or less than this amount. Some styles can not be raked at all. This may be the preferred method in order to keep a uniform small space under the fence, so the family pet can't get out. If the grade is steeper than that or the style can not be raked, "Stair Stepping" is necessary.

In this case, order end posts instead of line posts, because the second set of routed holes must be higher or lower than the first set in each post. Since it is tricky to estimate the amount of drop or rise, it is best to field route the second set of holes to the desired offset. Each panel could be slightly different for a custom fit.

The same principle may apply to a corner post, if a "stair step" must be made at the corner. Order an end post for that corner also.

It is not unusual to have an angle other than a 90 degree corner. You can use a corner post or a line post, depending on the angle. Basically, anything wider than 90 degrees, use a line post. Less than 90 degrees, use a corner post.

For the purposes of the online ornamental fence calculator, any angle must be entered as a corner post. The reason is that each line up to that angle must be entered in order for sections and line posts to be calculated properly. Each of the angled posts will be listed in the material list as a corner, but in reality, line posts must be substituted for those particular posts where appropriate.

To better understand the use of a line post versus a corner post, study the drawing below. Each of these must be entered in the calculator as a corner post, even though you intend to change it when ordering. If in doubt, you can always order a blank post (one with no holes) or an end post with the intention of cutting the other holes on the job, when you can better assess which is best.

You're Done! Obviously, this is just an overview of installing your new vinyl fence. It is intended to give you perspective before you start the project. As with any DIY project, give yourself plenty of time and have sufficient help when you begin. If this seems more than you want to take on, we suggest you locate a local fence installer. Although more expensive than doing it yourself, in the long run you will have a quality installation and a new fence system you will be proud of! If you enjoy Do-It-Yourself Project, this will be fun and rewarding project! For specific questions on Duramax fence installations please call Customer Service at 1-800-987-4337.