How long does a cedar fence last and how to make it last longer
Cedar is a good fence material for Vermont. It is naturally resistant to decay, it takes stain well, and it looks right in this landscape. A cedar fence installed correctly and maintained occasionally will last fifteen to twenty-five years. One installed with the wrong post depth or left completely untreated will start showing problems in five. Here is what makes the difference.
Post depth and concrete setting
The posts are the part of a fence that fail first. A post that is not set deep enough will heave in frost and lean over time. In central Vermont we set fence posts at a minimum of 42 inches, which gets us below the frost line for most sites. Posts go in concrete, not just packed gravel, and we let the concrete cure before we hang any boards.
The post itself should be a rot-resistant species or pressure-treated to at least UC4A rating for ground contact. Standard construction lumber in the ground will rot in a few years regardless of how well the rest of the fence is built.
What to do about the boards
Cedar boards do not need to be painted, but they benefit from a penetrating oil-based stain or sealer applied within the first year and reapplied every three to five years after that. The stain slows moisture absorption and UV degradation. Untreated cedar will gray out, which some people like, but it will also check and crack faster than treated cedar.
Back-priming or back-sealing the boards before installation, meaning treating the side that faces the post, is a step that adds time but reduces moisture uptake from the back face. We do this on all our cedar fence installations.
Things that shorten a fence's life faster than anything else
Soil contact on the boards is the biggest one. If your fence boards touch the ground, they will rot from the bottom up regardless of species. Keep at least two inches of clearance between the bottom board and the soil.
Sprinkler systems that hit the fence regularly are also hard on wood. If you have irrigation, aim it away from the fence line. And trim back any shrubs or vines that grow against the fence. They hold moisture against the wood and block airflow.
A cedar fence is a reasonable investment if it is installed right and given a little attention every few years. The maintenance is not complicated, just consistent.