How to Set Fence Posts That Won’t Rot
Keep moisture and insects from destroying your cedar fence posts.
IntroductionCedar has a reputation for durability, but unless a few guidelines are followed, cedar posts can fail in as few as five years. Three factors contribute to this early failure: poor drainage, low-quality wood and poor protection against insect damage. Here's how to install new cedar fence posts and avoid the problems that made your old posts rot.
- Caulk gun
- Posthole digger
- Acrylic caulk
- Wood preservative
Project step-by-step (5)
Pick the Right Posts
- Don’t use posts that contain sapwood. Instead, use heartwood, because it’s denser and more insect-resistant.
Treat the Post With Preservatives
- Soak the bottom of the posts in a wood preservative containing copper napthanate, such as Cuprinol.
- Note: Available at some paint stores and home centers, this wood treatment is specifically designed for in-ground applications.
- Place about 6 inches of aggregate in the bottom of the posthole to allow for drainage.
- Pro Tip: The bottom of the post should extend a few inches into the aggregate as shown.
Pour in Concrete
- Concrete should be 2-3 inches above the soil level.
- Trowel the top smooth and slope it so that water runs away from the post.
Caulk Around the Fence Post Base
- Apply high-quality exterior acrylic latex caulk, or silicone specifically designed to adhere to concrete, at the base of the post.
- Note: This will seal the gap between the concrete and post that's caused by freeze/thaw cycles.