シダーフェンス計算ツール

Western Red Cedar and Northern White Cedar carry natural oils and tannins that resist decay and insect damage without a chemical pressure treatment, which is the main reason cedar commands a higher price than pine for the same board. The post, rail and picket formulas behind this page are the same ones the general wood fence calculator uses for every species; this page simply defaults the material to cedar and its common board sizes, since that is the usual reason someone lands here specifically rather than on the general tool.

Cedar's tannins react with plain steel fasteners, leaving black streaks down the face of a picket, so stainless steel or hot-dipped galvanized nails and screws are worth budgeting for alongside the lumber itself. A privacy layout, the most common cedar fence style, has no gap between boards, so the picket count is just run length divided by board width before waste, the same formula this calculator applies for cedar's standard 1x6 or 1x4 dimensions.

Against the other premium species covered on this site, redwood shares cedar's natural rot resistance and similar fastener requirements at a different price point and regional availability, while pressure-treated pine relies on chemical treatment rather than natural oils and is the lower-cost option most builders compare cedar against. None of the three change the post or rail formulas; the difference is entirely in cost, expected service life, and the fastener and drainage details each species calls for.

Posts set in concrete benefit from a gravel drainage layer under the footing regardless of species, which the fence post calculator accounts for when sizing holes. Once the lumber order is set, the fence stain calculator figures out how much finish a cedar fence needs once it has dried enough to accept it. How much does a wood fence cost and how to install a wood privacy fence cover budgeting and the build sequence, and the fence materials guide and wood fence installation guide go deeper on both. The wood fence calculators hub links every other species and style.

Kiln-dried cedar is close to its final dimension and ready to stain right away, while green, unseasoned cedar needs 2 to 4 weeks of drying time outdoors, until moisture content drops below roughly 15 percent, before an oil-based stain will take properly. That distinction does not change the board, rail or post counts this calculator returns, but it does change the project timeline, since staining too early on green cedar traps moisture under the finish rather than protecting the wood.

Keeping the bottom of cedar pickets at least a couple of inches above soil or mulch, rather than letting them sit in contact with wet ground, is one of the more overlooked details on a cedar build, since cedar's natural rot resistance is strongest against airborne decay and weaker against sustained ground moisture wicking up through the end grain. A sacrificial pressure-treated rot board along the bottom of the run is a common, low-cost way to protect the cedar pickets above it without changing the picket count itself.

Cedar also varies by cut and grain orientation in ways that affect how it weathers: vertical-grain boards, cut so the growth rings run roughly perpendicular to the face, resist cupping and warping better than flat-grain boards over time, which matters more on wider pickets than on narrow ones. Where a supplier offers both, vertical-grain is usually worth the modest premium on any board wider than about 6 inches.

Climate also shapes how a cedar fence should be detailed: in consistently dry regions, cedar needs less aggressive moisture management than in humid or rainy climates, where ventilation gaps at the bottom of the fence and more frequent sealant reapplication matter more to keeping rot at bay. None of this changes the board, rail or post counts this calculator returns, but it does shape how the installation and maintenance schedule should be planned once the material order is placed.

Cedar heartwood, the reddish inner wood, carries the species' natural rot resistance, while the pale sapwood band near the bark does not, so a board with a significant sapwood streak on a structural or ground-contact piece is weaker against decay than one that is mostly heartwood, even though both are labeled the same species and grade. Checking boards for sapwood content, especially on posts, is worth the extra look when the lumber yard has mixed stock.

Regional cedar species also vary: Western Red Cedar, common in the Pacific Northwest, and Eastern White Cedar or Northern White Cedar, more common in the Northeast and Upper Midwest, differ somewhat in density and natural oil content, which affects weathering and workability more than it affects the board, rail and post counts this calculator returns for a given run length and height.

Checking a board's grade stamp or mill marking before it goes into the ground is a quick habit that catches a mismatched or mislabeled board before it becomes a structural post buried under concrete, where a mistake is far more expensive to correct.