2021
Posted by Sika Expert
Outdoor Projects: How to Install a Mailbox Using Sika® PostFix® Fence
Post Mix
A properly installed mailbox enhances both the functionality and curb appeal of your property. With the innovative, ready-to-use expanding foam mix, Sika® PostFix® Fence Post Mix, you can securely set a mailbox post in minutes and skip the hassle of heavy concrete bags, messy mixing, and long drying times. Here’s how to get the job done quickly and cleanly. Mark your spot, ensuring it’s accessible, away from potential hazards (like snowplows and other vehicles), and following local regulations
Supplies & Tools
- Sika® PostFix® Fence Post Mix
- Mailbox post (wood, plastic, or metal)
- Shovel or post-hole digger
- Level
- Safety goggles and gloves
- Scissors
- Gravel or soil (optional)
- Top covering (mulch, soil, etc.)
Step 1: Dig the Hole
Using a post hole digger or shovel, dig a hole to the proper depth and diameter depending on post size, soil conditions, and frost depths. See the product data sheet for coverage depth and diameter chart. If there is standing water in the hole, backfill partially with soil or gravel until water is no longer visible or pump the water out.
Step 2: Position the Mailbox Post
Place the mailbox post in the center of the hole. Use a level to ensure the post is straight on all sides.
Step 3: Prepare and Pour the Sika® PostFix®
With safety goggles and gloves on, and positioned immediately adjacent to the hole, roll the pouch in the direction of the arrows shown on the label, working towards the “burst seal” and allowing components A and B to combine.
Mix
Then, shake the bag vigorously for 15 seconds to further mix the two internal components.
Cut
Once mixed, cut open one corner of the bag with scissors.
Pour
Pour the entire contents into the hole immediately (the product begins to expand in seconds).
Pro Tip: Pour some of the material on the section of the post set to be below grade to improve support, sealing, and protection.
Step 4: Let It Expand and Set
Hold the post in place for 3–5 minutes while the foam expands and hardens. Within minutes, Sika® PostFix® will fully cure, stabilizing your post.
Trim
Trim away any excess material above ground level if needed.
Attach Mailbox
Once the foam is fully cured, attach your mailbox per the manufacturer’s instructions. Cover the application area with your choice of top covering (mulch, soil, etc.).
Why use Sika PostFix?
- Lightweight & Easy to Use: No hauling concrete bags or mixing with water.
- Fast Curing: Sets in minutes so you can finish the job quickly.
- Strong & Durable: Expanding foam provides excellent holding strength for long-lasting stability.
- Weather-Resistant: Works in a variety of soil conditions and climates.
Perfect for More Than Just Mailboxes
Sika® PostFix® isn’t just for mailboxes—it’s also ideal for setting fence posts, signs, gates, and even light posts
Wrap-Up
Installing a mailbox doesn’t have to be an all-day job. With Sika® PostFix® Fence Post Mix, you can achieve professional-grade results in a fraction of the time, with no mess, no stress. Your weekend to-do list just got easier!
Need the product?
Click here to get Sika® PostFix®
Let us know how your installation goes by tagging us on social media with your finished project! #SikaDIY