Product Description
OZ-Post® T4-850 Wood Post Anchor — 4″×4″ (Fits 3-1/2″×3-1/2″) — 34″ Length
- Heavy-Duty 34" Anchor Drives Deep in the Ground for Maximum Support
- Easy Install - Drives Into the Ground in Minutes Using a Jackhammer
- Installs in Asphalt & Other Hard Surfaces
- Wind Tested to 120MPH for Privacy Fencing - Install with Confidence
- Lengthen the Life of Your Wood Posts - Prevents Rot & Insect Damage that Happens Below Ground
- Reduces Post Heave - Designed to Reduce Frost Heave in Cold Climates
- Works with Fence Posts, Deck Posts (w/ OZ-Deck), & Any Other Outdoor Project that Uses 4x4s
- Hot-Dip Galvanized for Long Lasting Performance
The T4-850 OZ-Post is a 34" Long, Heavy-Duty Wood Post Anchor that Works with 4 x 4 (3-1/2" x 3-1/2" Actual) Wood Posts. This hot-dip galvanized anchor is approved for use with ACQ treated lumber. Forget about digging post holes and pouring messy concrete; those are the tools of the past. OZ-Posts are the future of outdoor post installation. These anchors can be driven into the ground in minutes, reducing time and effort on the project. Best of all, they perform similarly to a post hole that is filled with 6-8" of concrete, so they are more than capable of holding up your posts for the long term.
T4-850 anchors can actually be driven into the ground in 3 ways:
- Insert a spare piece of 4x4 into the OZ-Post sleeve so that it sits 5-6" above the sleeve height. Use a sledge hammer to pound down on the wood, driving the anchor in the ground. This technique is good installing a small number of OZ-Posts in a reasonable amount of time.
- Use the Manual Driving Kit, which uses weight and gravity, to drive the OZ-Post into the ground.
- Use the Jackhammer Driver Kit (JDK) along with a rented jackhammer to drive in as many OZ-Posts as you need. This is the quickest and least labor intense way, but may not be as cost effective for small projects (1-5 posts)
Why Choose This
- Cleaner jobsites — No digging, no concrete, minimal mess
- Drive-and-build workflow — Set posts and start framing the same day
- Extra depth — Longer anchor helps where post height or load is greater (always follow local code)
Specifications
| Model | T4-850 (Item #30160) |
| Fits Post Size | 4″×4″ nominal wood post (actual 3-1/2″×3-1/2″) |
| Anchor Length | 34″ overall |
| Top Sleeve Length | Approx. 6″ sleeve |
| Material / Finish | Hot-dip galvanized steel; compatible with pressure-treated (ACQ) lumber |
| Driver Options | Manual Driver Kit (MDK-13) or Jackhammer Driver Kit (JDK-10) |
| Included | T4-850 post anchor (post fasteners not included) |
| Typical Usage | Wood fencing, small signs, landscape structures (verify code for decks/rails/gates) |
Installation
Lay out post locations and call 811 to locate utilities. Using a manual driver or jackhammer driver kit, drive the T4-850 to grade keeping it plumb. Insert the 4×4 post and fasten through the sleeve. If securing holes land below grade, inject a polyurethane adhesive/sealant to help reduce moisture intrusion. In rocky/bedrock conditions, pre-drill or use an alternate footing.
Resources: Manufacturer’s Warranty
Buying Guide
- Soil & load: Choose T4-850 for deeper embedment on taller/heavier runs. For very dense/rocky soils, T4-600 (24″) may drive easier.
- Project type: For light posts like mailboxes, MB-24 (27″) is a good fit.
- Code check: Always follow local building requirements for footing type and post sizing.
Frequently Asked Questions
- Do I need to pour concrete?
- No. T4-850 is a drive-in anchor designed to eliminate digging and concrete in qualifying applications.
- How does T4-850 compare to T4-600?
- T4-850 is 34″ long (deeper embedment) while T4-600 is 24″. Pick based on soil conditions, post height, and load.
- Is it compatible with pressure-treated lumber?
- Yes. The galvanized construction is suitable for ACQ-treated wood.
- Which tools do I need?
- Use a manual driver kit for small runs or a jackhammer driver kit for faster installation on larger projects.
- Can it drive through rock or asphalt?
- It can be driven through asphalt and will often deflect around small rocks; solid bedrock typically requires pre-drilling or a different foundation.
Comparison
| Option | Strengths | Considerations | Best For |
|---|---|---|---|
| T4-850 (34″) (this item) | Deeper embedment; ideal for taller posts/heavier runs | More driving effort than shorter models | Fence lines where extra depth is preferred |
| T4-600 (24″) | Easier driving in hard/rocky soils | Shallower embedment | Dense soil sites; shorter posts |
| MB-24 (27″) | Great for simple, light-duty posts | Not intended for taller/heavier loads | Mailboxes and similar projects |
Need help choosing between OZ-Post anchor sizes for your soil and fence height? Contact us and we’ll help you plan a clean, durable installation from anchor to fasteners.
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Product Reviews
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Post and Pier foundations
Great product for no concrete foundations.
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Easier than Concrete
This is the 3rd fence I've installed. For the first 2 I used the dug holes and poured concrete. This time, I had to have the fence up ASAP to meet regulations (red tape), so I decided to try post anchors with a jackhammer. While it didn't cut the time in half, it did save me a couple of hours and the fence seems to be as sturdy as the first 2. So far, I'm very happy.
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Worked As Advertised
Replaced 4 fence posts with ozposts in about 2 hrs. Set 'em right in the same hole then covered it up Expensive but still worth it for this old timer. Doing more soon
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Very Quick and Easy
I used the post anchor to replace a stop sign post that had been snapped off by a careless driver. Since the post had snapped off at ground level, I could re-use the shortened 4x4. Anchor was relatively easy to drive with a large sledge hammer. It was much quicker than buying a new 4x4, digging a hole, mixing and pouring concrete, etc.
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Oz post
great quality and service.
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Nice
I used because I needed to remove the fence post from ground thus cement was not an option. I thought the Oz T4-850 would not keep the post stable but I was wrong. The post mounted in this anchor is actually more stable than the ones in cement.
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Purchase of Oz-Post T4-850
I chose your business to order from because I could order the exact number of posts I needed rather than having to buy in case lots. Your web site and order fulfillment processes worked just fine as well.
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Purchase of Oz-Post T4-850
I chose your business to order from because I could order the exact number of posts I needed rather than having to buy in case lots. Your web site and order fulfillment processes worked just fine as well.
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Oz-Post T4-850 - 4x4 Post Anchor (Case of 6)
Oz-Post T4-850 - 4x4 Post Anchor (Case of 6)
