How to Build a Post and Rail Fence on a Slope

This blog post will tell you how to build a post and rail fence on a slope. I can’t imagine a more obvious blog post title, right? But for whatever reason, there are many people who think about building fences on hills and mountains. The fact is that an uneven terrain or steep hillside makes things much easier for us. Why? It’s because we install the posts closer together!

The post and rail fence is a trellis-style fence that works well on terrains that are on a slope. Learn how to build a post and rail fence for your garden, or to enclose an outdoor patio.

🛠️ What This Is About

Installing a post‑and‑rail fence on a slope—ensuring stability while making it visually pleasing on uneven ground.

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📏 Two Common Techniques

1. Contour (Raked) Fence
   • Rails follow the slope.
   • Posts remain vertical.
   • Best for mild slopes (under ~15°).
2. Stepped Fence
   • Rails and panels stay level, but each section “steps” down the hill.
   • Ideal for steeper slopes (> 15°).

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📋 Materials or Tools You’ll Need

• Posts: concrete, metal T-posts, or pressure‑treated wood
• Rails: typically 1×6 or 2×4 boards
• Fasteners: exterior‑grade screws or lag bolts
• Tools: post hole digger, level/plumb bob or laser, string line, concrete mix, saw
• Post anchors: especially for sloped surfaces

⚙️ Step‑by‑Step Instructions

1. Prep & Measure

• Mark fence line using stakes and mason line.
• Measure slope (“rise over run”) to determine how steep it is.

2. Choose Method

• Slope < 15° → Contour (raked) fence.
• Slope > 15° → Stepped fence.

3. Install Posts

• Dig holes (~⅓ of post length deep).
• Use anchors or concrete to secure posts–ensure vertical alignment with level or plumb bob.
• For stepped fence: string line marks top cuts for each post.

4. Attach Rails

• Contour method: run rails at angle following slope. Set height via string line and attach .
• Stepped method: build level panels. Each drops uniformly down slope. Posts are pre-cut at top to match step drop .

5. Install Fillers/Pickets (if used)

• Leave ~4″ gap under fence bottom for water drainage and ground movement.

6. Finish & Inspect

• Trim post tops if needed for uniform look, using laser/string and saw
• Check alignment and adjust as needed.

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✅ Pros and Cons

Method	Pros	Cons
Contour	Smooth, follows landscape, no bottom gaps	Limited to mild slopes, tricky on steep hills
Stepped	Works on steep slopes, simple to build	Noticeable gaps, stair‑look visual

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💡 Expert Tips

• Use anchors designed for slopes for added stability .
• A laser level or tight string line helps keep top rails even.
• “Cut‑after” method: leave posts long, install, then trim tops evenly for clean finish .
• Keep bottom of rails at least 3–4″ above ground to allow drainage.

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👷 Who Should Use This

• Homeowners with sloped yards wanting a durable, attractive fence.
• DIYers comfortable with leveling tools and concrete.
• Anyone looking to avoid gaps at bottom or wanting smooth transitions.

Building an angled fence that follows the contours of your yard. This is a more time consuming method but it will be less expensive since you won’t have to purchase as much material to level out your yard.

If you decide on leveling out your yard between posts, here are some tips for doing so:

Use wedges or other stabilizing materials under each post to ensure that they are stable once installed in the ground. If possible, drive them into solid soil or fill with concrete rather than just using wood wedges because wood wedges will fail over time and could cause your posts to shift after installation. Cement filled metal posts are also available for this purpose if you don’t want to use concrete; however, these can cost more than concrete filled metal posts

When you’re building a fence on a slope, it’s important to pay attention to the details. If you don’t, your fence could be unsafe or even collapse.

In this article, we’ll show you how to build a fence on a slope by using post and rail fencing. We’ll also discuss some common mistakes that people make when they build fences on slopes and how to avoid them.

If you want to learn more about constructing fences, check out our “How to Build a Fence” guide for everything from choosing posts to installing pickets and gates.

Building a fence on a slope can be a challenge, but it’s not impossible. The key is to build the fence so that the posts are level with each other.

First, you’ll need to install your fence posts on level ground. Use stakes and string line to make sure all of your posts are plumb (straight up and down), then dig holes for them.

Next, add concrete footings around each post. You’ll need to create a trench around each post at least 2 feet wide and as deep as the height of your fence (3 feet or less). Add concrete footing forms around each post and fill with concrete.

Step 3: Install Fence Rails

Next, install the rails for your fence — these should be attached to the bottom of your posts with lag screws and washers or carriage bolts. For extra support, use metal angle brackets attached directly to the post instead of attaching them directly to the rail itself. You might also want to use wood blocks between rails if they’re spaced far apart from each other; this will keep them from sagging over time. If you plan on adding panels (such as lattice) between sections of railings, attach these now as well

📌 Quick Checklist

Final check for plumb, level, gaps

Decide on contour (raked) vs stepped style

Measure slope angle

Set posts vertical, with slope-specific anchors

Run rails—angled or level based on method

Leave bottom clearance for drainage

Trim post tops uniformly after install

Item	Description
1. Railroad Ties	Wooden Ties: Typically more expensive, offering a natural look. Plastic Ties: More budget-friendly, easier to handle but less natural aesthetics.
2. Tools Required	Level: To ensure the wall is even. Shovel: For digging the trench. Measuring Tape: For accurate measurements. Hammer: For driving in spikes or nails. Saw: To cut ties if needed.
3. Planning the Layout	Determine the Location: Decide where the wall will be built. Measure the Area: Use the measuring tape to mark dimensions. Angle of Slope: Assess the slope that needs to be retained.
4. Building the Wall	Excavate a Trench: Dig a trench where the wall will sit. Lay the First Row: Position the first row of ties and check for level. Build Upwards: Stack ties with staggered joints for stability. Install Drainage: Consider drainage to prevent water build-up behind the wall.
5. Finishing Touches	Backfill: Fill the area behind the wall with soil. Trim Edges: Cut any excess ties if needed. Add Plants: Option to landscape around the wall for aesthetics.