How to Install a Granite Mailbox Post
A granite mailbox post is one of the most durable and timeless upgrades you can make to your home’s exterior. Built to handle harsh winters, snowplow impact, and years of weather exposure, granite offers unmatched strength and classic New England curb appeal.
Here’s a step-by-step guide to installing one properly.
What You’ll Need
Tools & Materials:
Steel pick/tamp (to loosen soil and remove stone)
Post hole digger
Tape measure
Spray paint
Granite post
Mounting bracket
Underboard
Mailbox
Hammer drill
Drill
Screws
Anchor bolts
Step 1: Mark the Location & Call Dig Safe
Before digging, mark the location for Dig Safe.
Your mailbox post should be positioned 30 inches back from the edge of the road. Use your tape measure and spray paint to clearly mark the location.
Contact Dig Safe and wait until the area has been cleared for underground utilities. This step is critical for safety and required before excavation begins.
Step 2: Dig the Hole
Once Dig Safe has cleared the area, you can get to work.
Using your steel pick/tamp and post hole digger:
Dig the hole 30 inches deep
Make it approximately 12 inches wide
The steel pick is especially helpful for loosening compacted soil and removing stones — something common in New England soil conditions.
Step 3: Set the Granite Post
Once your hole is dug, carefully place the granite post into the hole.
Granite posts are heavy — around 300 pounds. We use a crane system to lift and lower ours into place to prevent the risk of injury and ensure precise placement.
After the post is in the hole:
Align it with the angle of the street.
Make sure it is straight and properly positioned before securing it.
level, level, level
Alignment matters. Taking your time here ensures a clean, professional look.
Step 4: Secure the Post
With the post aligned, begin securing it by tamping in layers of gravel and dirt.
Add a layer of gravel.
Tamp it down firmly.
Add soil.
Tamp again.
Repeat this process in layers. Proper tamping is key — after enough compacting, the post should not move at all. A well-secured granite post will withstand freeze-thaw cycles and resist shifting over time.
Step 5: Measure & Install the Bracket
Next, measure 41–45 inches up from the road surface and mark the location on your granite post. This is where the top of your bracket will sit (standard mailbox height range).
Center your bracket on the post and mark the drill holes.
Using a hammer drill:
Drill the holes into the granite.
Attach the bracket using anchor bolts.
Granite requires the proper masonry bits and anchors. Precision drilling ensures a secure and long-lasting attachment.
Step 6: Attach the Underboard & Mailbox
Once your bracket is secured:
Attach the underboard to the bracket.
Make sure it is level.
Secure it with screws.
Attach your new mailbox to the underboard.
Check that the mailbox door opens freely and that everything sits straight and secure.
Personalize Your Installation
To really elevate the finished look, consider adding:
Custom street name decals
Reflective address numbers
A decorative granite cap
Small details like these enhance visibility, improve curb appeal, and give your mailbox a polished, personalized finish.
Built to Last
When installed correctly, a granite mailbox post:
Holds firm through winter freeze and spring thaw
Adds long-term value to your home
A properly installed granite post is a functional and permanent upgrade.
Thinking about upgrading to granite?
Mailbox Doctor specializes in professional granite mailbox post installations built to withstand New England conditions — safely, securely, and done right the first time.
