Fence & Wall Layout Sheet

Sections, line posts and the ones on the ends

A run of fence has one more post than it has sections, which sounds obvious and is still the commonest arithmetic slip in a fence order. Eight sections need nine posts. Where the sheet helps is that a real fence is several runs meeting at corners, and the post on a corner belongs to both runs — count it once, not twice.

Then the ends and the gates. Every corner and every end is a terminal post, which on a chain link fence is a heavier post than the line posts between them. Every gate opening needs a post on each side, and one of those is usually already there.

Spacing, and when to close it up

Eight feet between posts is the usual maximum and it matches standard 8 foot rail stock with no waste. Drop to six in a windy spot, or where the boards are heavy, or where the ground moves. The saving from stretching to ten feet is one post, and the cost is a fence that sags.

The hole matters more than the post

Three rules, and they are all about the hole:

• Diameter is three times the post width. A 4×4 post — actually 3 1/2 inches — wants a 10 to 12 inch hole. Less concrete than that and the post is a lever with nothing to push against.
• Depth is at least a third of the height above ground, and always below your local frost line, whichever is deeper. Frost heave lifts a shallow post out over a winter and it never goes back.
• Gravel goes in the bottom. It gives water somewhere to run, and the depth of gravel comes off the depth of concrete, which the sheet accounts for.

An 80 pound bag yields 0.60 cubic feet, a 60 pound bag 0.45, a 50 pound bag 0.375. Those are the numbers that turn a hole into a bag count.

A retaining wall buries its first course

The height you want to see is not the height you build. The bottom course sits below grade on a compacted gravel base, so a wall standing 24 inches proud of the ground is five courses of 6 inch block, not four. Drainage stone goes behind it, and on anything much over three feet you are into engineering and permits rather than a weekend.