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Fencing & Decking Material Calculators

Accurately calculate 4x4 posts, 2x4 horizontal rails, dog-ear pickets, post-hole concrete bags, composite & wood deck boards, framing joists, and hidden fastener boxes.

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Fence Structure & Deck Framing Engineering Standards

Contractor standards for post hole depth, frost lines, composite joist spacing, and ledger flashing.

Post Hole Depth & Frost Line Rule

Fence posts must be set at a depth of 1/3 to 1/2 of the above-ground post height (typically 30–36 inches for 6ft privacy fences) and extend below the local frost line to eliminate winter ground heaving. Use 2 bags (50lb fast-setting) per hole.

2-Rail vs 3-Rail Privacy Fencing

6ft wood privacy fences strictly require 3 horizontal 2x4 rails (top, middle, and bottom). Installing only 2 rails on 6ft fences allows cedar/pine pickets to warp and curl severely under summer sun exposure.

Composite Joist Spacing (12" vs 16" OC)

While standard treated lumber supports 16" on-center joist spacing, composite decking (Trex, TimberTech) requires 12" on-center framing for diagonal patterns and eliminates deck board sponginess.

Deck Ledger Board Flashing

90% of structural deck collapses occur at the ledger board connection. Install continuous Z-flashing and membrane tape over the ledger board and fasten with 1/2-inch hot-dipped galvanized or structural ledger screws staggered into house rim joists.