How to Plan, Price, and Build an Open Cedar Post-and-Rail Fence

A cedar split rail fence looks simple: posts, horizontal rails, and open space. Yet planning can go wrong quickly if nominal rail length is mistaken for installed post spacing, incompatible components are mixed, or a retailer’s component price is treated as the full project cost.

The reliable approach is to choose one compatible rail-and-post system, calculate quantities by actual fence sections, and adapt the installation to the property. Soil, drainage, frost depth, slopes, gates, wind, animal pressure, and local requirements can all affect the final design.

This is a planning guide, not a site-specific construction specification. Product instructions and applicable local requirements should control dimensions, footing details, and containment design.

What a cedar split-rail fence is—and where it fits

The common modern cedar split-rail fence is a component-built system rather than a row of prefabricated panels. Separate cedar rails have shaped or tapered ends that fit into mortises—openings cut into posts. As each post is installed, the rails connect it to the next post.

This article focuses on that mortised post-and-rail configuration. “Split rail” can also describe zigzag fences made from stacked, interlocking rails, double-post designs, and freestanding buck-and-rail fences. Those forms use different layouts and should not be estimated or installed as though they were mortised systems.

The defining visual feature is openness. A two- or three-rail arrangement can mark a property edge, frame a driveway, separate landscape areas, or create a decorative rural-style boundary without blocking much of the view. Whether that rustic appearance suits the property is a design preference, not an objective performance advantage.

Suitable applications include:

• Open property-line definition
• Decorative roadside or driveway boundaries
• Landscape and garden-area definition
• Visual separation between parts of a large yard
• A framework for a separately specified mesh or wire barrier

A standard open split-rail fence is not, by itself, a secure enclosure for dogs, other small animals, or small children. The wide spaces between and below the rails generally require a separate containment layer. Home Depot’s installation guidance similarly says an open split-rail fence can define a boundary but will not confine pets or other small animals (Home Depot split-rail installation video).

Agricultural or wildlife-control use calls for more analysis than selecting two, three, or four rails. The animal, its behavior, expected pressure on the fence, terrain, gate design, visibility, and any mesh, woven wire, or electric system all matter. Treat the cedar rails as one part of the enclosure—not as proof that the finished system will contain livestock or deter wildlife.

Rails, posts, and configurations: how the system goes together

A mortised cedar split-rail system usually has three primary post types:

• Line post: Continues a straight run. Its mortises pass through the post so rails can enter from both directions.
• End post: Terminates a run. Its mortises extend only partway through, capturing the ends of the final rails.
• Corner post: Changes direction. Its mortises are cut on adjoining faces so one run can meet another.

A straight run with four sections looks like this:

END          LINE          LINE          LINE          END
 POST         POST          POST          POST          POST
  |====rails====|====rails====|====rails====|====rails====|
       Section 1     Section 2     Section 3     Section 4

The two end posts terminate the run. Each line post serves the section on both sides.

A corner changes the geometry:

Run A  ==================== [CORNER POST]
                                  ||
                                  ||
                                  ||
                                Run B

The corner post’s mortises must face the directions of both runs. Once the holes and rail elevations have been established, rotating a wrongly oriented post to serve one run will misalign it with the other.

Two rails versus three rails

Each section is bounded by the same two posts regardless of whether it has two or three rail levels:

Two-rail section                Three-rail section

POST             POST          POST             POST
 |================|             |================|
 |================|             |================|
                                  |================|

For a fence with S sections:

• Two-rail design: 2 × S rails
• Three-rail design: 3 × S rails
• Four-rail design: 4 × S rails

Adding a level therefore adds one rail to every section. It may also require taller three- or four-hole posts rather than simply adding rails to posts designed for two levels.

Hoover Fence lists two- and three-rail cedar systems as readily available and describes its four-rail material as special order with a lead time of four to six weeks. That is specific to its product offering, not evidence that four-rail cedar systems have the same availability in every market (Hoover Fence cedar split-rail specifications).

Components beyond posts and rails

A realistic order may also need:

• Gates
• Gate posts
• Hinges
• Latches
• Gravel
• Optional concrete
• Mesh, woven wire, or another containment layer
• Appropriate attachment hardware
• Finishing products, if desired
• Replacement or waste material

Do not assume these items are included with the posts and rails.

Gate openings deserve particular attention. Home Depot describes gate posts as thicker than ordinary posts and says their openings do not pass completely through. Tractor Supply recommends end-type posts at gates. These examples show why the opening, post type, hardware, and footing should follow the selected gate system rather than an improvised line-post layout (Tractor Supply split-rail installation guide).

A gate also introduces loads that an open rail section does not. Obtain the gate manufacturer’s requirements before selecting posts, hole dimensions, or a setting method.

Rail lengths and seller-specific grades

Commercial cedar listings in the reviewed material include 8-foot and 10-foot rails, while general split-rail installation guides also discuss 11-foot rails. These are product lengths, not automatic post-spacing dimensions.

Hoover Fence uses the labels Pony, Standard, and Jumbo for three Western red cedar rail options:

Seller label	Listed length	Average girth	Approximate weight	Seller’s bundle quantity
Pony	8 ft	9–12 in	9–10 lb	200
Standard	10 ft	10–12 in	14 lb	155
Jumbo	10 ft	At least 12 in	20 lb	110

These dimensions, weights, and bundle counts are supplier-specific ordering information, not universal specifications. Hoover Fence also says its own grades use common mortise and tenon dimensions, allowing its posts and rails to work together across those grades (Hoover Fence cedar rail options).

Another supplier may use the same label for a different girth, taper, species, post size, or mortise pattern. Compare measurable specifications, not names.

How rail length changes the project

Shorter rails create more sections over the same run. More sections mean:

• More posts
• More post holes
• More excavation and tamping
• More opportunities for alignment error
• Potentially higher labor and delivery costs

For example, a lower-priced 8-foot rail does not necessarily produce the lower-cost fence if it requires substantially more posts and excavation than a compatible 10-foot system.

Do not use nominal rail length as post-center spacing without confirmation. Rail ends must seat, engage, or overlap inside the post mortises. Home Depot’s general guide recommends center-to-center spacing approximately 10 to 12 inches shorter than rail length to allow overlap, but the correct deduction belongs to the selected product rather than a universal formula (Home Depot split-rail installation video).

Before ordering, obtain written confirmation of:

• Actual rail length
• Tenon dimensions and shape
• Mortise dimensions
• Intended center-to-center post spacing
• Cedar species
• Seller’s grade definition
• Treatment status and intended ground-contact use
• Two-, three-, or four-rail compatibility
• Current stock and lead time
• Bundle minimums
• Delivery area and unloading requirements
• Freight charges
• Return terms for unused or incompatible components

Mixing suppliers is risky unless both confirm compatibility.

How to calculate cedar rails and posts

Count cedar split-rail material by sections, not by applying a generic linear-foot multiplier.

A section is the span between two adjacent posts. Once the section count is known, the rail count follows from the number of rail levels, and the preliminary post count follows from the number of section boundaries.

Calculation sequence for each uninterrupted run

1. Get the actual installed section spacing. Use the supplier’s center-to-center dimension, not merely the rail’s nominal length.

2. Divide the run length by section spacing.

text Raw section count = run length ÷ actual center-to-center spacing

3. Round up for a preliminary whole-section count. Rounding up is a planning step, not proof that rigid rails will fit. Before finalizing quantities, reconcile the physical run by adjusting the fence length or an opening, using a supplier-approved short terminal section, or making only a supplier-permitted modification.

4. Calculate rails.

text Rail quantity = whole sections × rail levels

5. Calculate the preliminary post count for a simple run.

text Post quantity = whole sections + 1

6. Classify every post. Identify ends, lines, corners, and gate posts. Do not order every post as a line post and expect to sort out the mortise patterns during installation.

7. Adjust for gates, shared corners, and approved short terminal sections.

Why nominal rail length is not enough

A 10-foot rail does not necessarily produce 10-foot centers. The shaped ends extend into the posts, and some systems require overlap within a through-mortise. If specified centers are shorter than nominal rail length, laying out posts at the full rail length can leave too little engagement or prevent assembly.

The supplier’s installed center-to-center spacing should therefore drive both staking and quantity calculations.

Documented 100-foot example

Menards’ suggested two-rail design for 100 feet lists:

• 20 ten-foot rails
• 9 line posts
• 2 end posts
• 10 sections
• 11 total posts

The arithmetic is consistent with two rail levels across 10 sections: 10 × 2 = 20 rails. A straight 10-section run has 11 post positions. Menards presents this as a suggested design and material list, not a universal kit, guaranteed complete bill of materials, or code-compliant prescription (Menards 100-foot cedar split-rail material list).

Do not automatically apply that list to another 100-foot project. Another system may use different centers, post dimensions, rail engagement, or termination details.

Corners and gates

A corner often changes the post type without increasing the physical post count. If one correctly mortised corner post serves both runs, it replaces the separate end posts that might otherwise terminate those runs.

Run 1: End — Line — Line — Corner
                               |
                              Line
                               |
                              End
                             Run 2

Calculate each run separately so section lengths remain clear, then count the shared corner only once in the combined post total.

A gate divides a fence run and creates new termination points. Subtract the confirmed gate opening from the rail run, calculate the sections on each side independently, and follow the selected gate system’s instructions for posts, hinges, latch, opening dimensions, and footings.

Quantity worksheet

Complete one row for every straight run between an end, corner, or gate:

Input	Run A	Run B	Run C
Measured run length
Gate/opening width deducted
Net rail run
Actual section spacing
Raw sections
Preliminary whole sections
Physical fit reconciled?
Rail levels
Rails required
Base posts: sections + 1
End posts
Line posts
Corner posts
Gate posts
Approved short terminal sections
Project-specific waste allowance

After completing the table, combine shared corner posts only once. Set a waste allowance according to the actual product, return policy, likelihood of split or malformed pieces, and distance from replacement stock—not an invented universal percentage.

Sketch the entire route before ordering. Number every post, mark its type, and draw the direction of each mortise. This is especially useful on irregular boundaries, slopes, and layouts with multiple gates.

Material prices—and what the advertised numbers leave out

The prices below are retailer snapshots observed in the supplied listings and may change by date, location, configuration, inventory, tax, and delivery method. Except for the dated Menards promotion, the listings did not provide a price date; verify every figure before ordering.

Example rail and post prices

Mill Outlet Lumber displayed a standard-weight 8-foot rail at $13.75 (Mill Outlet Lumber cedar split-rail listings). American Fence & Supply displayed a 10-foot rail at $16.55 and a jumbo 10-foot rail at $21.75 (American Fence & Supply split-rail catalog). These listings do not establish that similarly named components from the two sellers are interchangeable.

American Fence & Supply also displayed these post prices:

Post configuration	Two-hole post	Three-hole post
Line	$18.45	$21.59
End	$18.45	$21.59
Corner	$18.45	$21.59

Its catalog also listed a split-rail latch at $7.90. Prices and configurations require confirmation before purchase.

Cedarbrook displayed a $23 base price for a three-hole post, with $4 options for an end or corner configuration. The listing describes the post as 6 feet 6 inches long and compatible with 8- and 10-foot rails, but buyers still need to verify all system dimensions before comparing it with another seller’s posts (Cedarbrook three-hole post listing).

The 100-foot price example needs context

Menards displayed an approximate price of $564.39 for its suggested 100-foot, two-rail cedar material list. It also advertised a $502.31 value after a $62.08 mail-in credit, valid through September 6, 2026. The credit was for future in-store purchases, not an immediate reduction in the original transaction (Menards 100-foot cedar split-rail material list).

The same page describes the list as a suggested design rather than a complete kit, warns that prices and materials may vary, does not guarantee code compliance or completeness, and states that delivery is extra. The figure is therefore a dated material-list example—not an installed price or universal 100-foot budget.

Gates and freight can reshape the budget

American Fence & Supply displayed gate prices from $295.90 for a smaller two-rail gate to $495 for a larger three-rail gate. Its abbreviated catalog descriptions make it important to confirm dimensions, rail count, included hardware, and required posts on the individual product page (American Fence & Supply split-rail catalog).

Freight can erase apparent savings from a distant supplier. Hoover Fence says most orders ship by common carrier and estimates freight for small orders beginning around $425. Bundle quantities, unloading requirements, and large-truck access can also affect whether a remote order is practical.

Project budget worksheet

Price the exact quantities from the section worksheet:

Cost category	Quantity	Unit price	Extended cost	Notes
Rails—type/length 1
Rails—type/length 2
Line posts
End posts
Corner posts
Gate posts
Gates
Hinges
Latches
Gravel
Optional concrete
Mesh or wire				Separate design
Attachment hardware
Delivery or freight
Taxes
Tool purchase or rental
Site clearing/preparation
Excavation or rock charges
Labor
Finishing products
Waste/replacement material				Project-specific
Total

A single installed cost per linear foot would imply comparability the available evidence does not provide. Regional labor, freight, terrain, rock, disposal, gates, frost requirements, and supplemental containment can create materially different totals.

Planning the route before any holes are dug

Resolve the route before buying material or excavating. A small layout change can alter section counts, post types, gate placement, and whether standard rails fit.

Pre-dig checklist

• Confirm the legal property boundary rather than relying on mowing lines, old fences, or informal markers.
• Identify known easements and access rights.
• Check applicable setbacks and fence-height rules.
• Determine whether a permit or plan review is required.
• Review HOA or similar private restrictions.
• Discuss a shared boundary with the adjoining owner.
• Establish gate positions, widths, swing direction, and clearances.
• Identify drainage paths, buried irrigation, and private utilities.
• Contact 811 before digging and follow the locator’s instructions around marked services.
• Confirm local frost-depth and footing requirements.
• Identify wet areas, soil movement, rock, fill, erosion, and steep grades.
• Assess wind exposure, animal pressure, and gate loads.

Lowe’s and Tractor Supply both identify property lines, easements or permits, association rules, neighboring owners, and buried-utility checks as pre-installation considerations. Both direct readers to contact 811 before excavation (Lowe’s split-rail installation guide).

These steps are not replaced by a retailer’s material list. Menards expressly says its suggested list is not guaranteed complete or compliant with local codes.

Stake and reconcile the layout

Stake every end, corner, and gate opening. Run string between them, then mark post centers using the installed spacing specified for the chosen system. Compare the field layout with the material worksheet before ordering or digging.

A nominal 100-foot boundary may not accommodate ten identical sections once actual center spacing, corners, and gate openings are included.

Lowe’s recommends allowing a split-rail fence to follow a slope and notes that an extreme grade may call for a different fence type. Even on an ordinary slope, each post still needs the correct mortise elevation and orientation.

When full sections do not fit

If a run does not divide evenly, the principal options are:

1. Adjust the total fence length.
2. Move or resize an opening.
3. Use a supplier-approved shorter terminal section.
4. Modify a rail or post only if the supplier permits it and confirms adequate engagement.
5. Change to a system with more suitable spacing.

Lowe’s notes that precut rails may not fit a landscape exactly and describes changing the overall length, adjusting openings, adding shorter end sections, or carefully trimming rails as possible responses. It also warns that trimming rail ends to fit can be awkward (Lowe’s split-rail installation guide).

Settle short-section details during layout. Cutting a rail after most holes are dug may change the end shape and reduce its engagement in the mortise.

Before deciding hole depth or backfill, obtain site-specific answers about:

• Required frost depth
• Soil bearing and movement
• Seasonal saturation and drainage
• Terrain and erosion
• Fence height
• Wind exposure
• Livestock or impact pressure
• Gate weight and leverage
• Post treatment or intended ground-contact use
• Manufacturer instructions
• Applicable permit or code conditions

The available sources do not supply universal specifications for these conditions. Where they matter, use the selected manufacturer’s instructions and local professional or regulatory guidance.

Installation sequence and the post-setting decision

The general assembly process is straightforward, but the details remain conditional on the selected system and site.

A qualified installation sequence

1. Verify approvals, boundaries, and utility markings.
2. Stake the route and string each run.
3. Mark post centers from the selected system’s installed spacing.
4. Confirm the post schedule: end, line, corner, and gate.
5. Excavate holes to the product- and site-appropriate diameter and depth.
6. Provide suitable base drainage where the approved method calls for it.
7. Set the first end or terminal post.
8. Check elevation, mortise direction, and plumb.
9. Insert rails as adjoining posts are placed.
10. Recheck string-line alignment, spacing, rail engagement, and ground clearance.
11. Backfill and tamp according to the approved method.
12. Use temporary bracing where needed to hold alignment during assembly.
13. Install gates and supplemental barriers to their separate specifications.
14. Inspect after settlement and re-tamp posts that loosen.

Lowe’s specifically recommends setting end posts first, checking posts for plumb, inserting rails as work progresses, tamping the backfill, and using temporary bracing where needed.

There is no universal post depth

The reviewed guidance differs materially:

• Home Depot specifies at least 18 inches for its demonstrated 3.5-foot fence.
• Cedarbrook says its 6-foot-6-inch three-hole post is typically set about 27 inches deep.
• Hoover Fence describes posts in its system as typically installed about 30 inches deep.
• Lowe’s and Tractor Supply describe placing approximately one-third of the post underground (Tractor Supply split-rail installation guide).

These figures should not be averaged into one rule. They may concern different post lengths, fence heights, soils, products, and assumptions. Follow the selected product instructions and whichever applicable local requirement is more demanding after accounting for frost depth, drainage, soil movement, terrain, fence height, wind, gates, and other loads.

Also distinguish post burial depth from total hole depth. Lowe’s one-third method calls for excavation below the post to accommodate gravel, so those measurements are not interchangeable.

Soil, gravel, or concrete?

The sources do not support an absolute rule.

Lowe’s and Tractor Supply describe gravel beneath the post for drainage and compacted backfill. Hoover Fence describes approximately 30-inch direct burial without concrete and recommends gravel backfill. Home Depot says posts can be backfilled with gravel or soil and that concrete may be needed depending on soil conditions.

Treat concrete as a site-specific structural and drainage decision:

• Compacted native soil may be permitted by some products on suitable sites.
• Compacted gravel may be permitted as backfill and used for drainage.
• Concrete may be required by local rules, manufacturer instructions, soil conditions, or structural loads, particularly at gates.

Concrete is neither universally required nor universally harmful. Confirm the method with the selected product instructions and applicable local requirements.

Whatever backfill is approved, check plumb in two directions and verify that the post remains on the string line while the backfill is tamped. Temporary bracing can help maintain alignment while adjoining rails are inserted and the post is secured.

Lowe’s and Tractor Supply recommend at least 6 inches between the ground and the lowest rail. Treat that as general planning guidance subject to the chosen post’s mortise positions, slope, vegetation, drainage, and any separately designed containment layer.

Inspect the fence after the soil settles and re-tamp posts that loosen or lean, especially after wet conditions. Hoover Fence specifically warns that installed posts may need re-tamping after settlement.

Optional: hand-splitting rails

A documented garden-fence project used an auger, mortise axe, felling axe, crosscut saw, and small gravel for drainage. It demonstrates that traditional hand fabrication is possible, but it is not a complete engineering, safety, or installation standard (hand-built cedar split-rail project).

Weathering, upkeep, and containment limitations

Appearance maintenance and structural performance are related but not identical.

Cedar can be left unfinished to weather toward a silver-gray color. If retaining more of the original color is the goal, an exterior finish intended for the particular cedar product may be considered. The available evidence does not establish a universal staining interval for cedar split-rail fencing or support a single service-life claim.

Posts deserve different attention from rails because posts are exposed directly to soil, splash, and moisture at the ground line. Periodically inspect:

• Post bases and the ground line
• Drainage and ponding
• Leaning or movement
• Loose or settled backfill
• Rail ends inside mortises
• Cracked or damaged rails
• Gate alignment and sag
• Mesh or wire attachments, if present
• Vegetation trapping moisture around the fence

Do not interpret general statements about cedar’s natural properties as a guarantee against rot, insects, fungus, moisture damage, warping, or ground-contact deterioration. Species, grade, treatment, drainage, climate, installation, and exposure all affect performance.

Containment is a separate design problem

The wide openings of a standard cedar split-rail fence make it unsuitable as a complete barrier for pets, other small animals, or small children. Home Depot and Tractor Supply both state this limitation in their installation guidance.

Adding mesh or wire may preserve the visible cedar framework while closing openings, but the additional layer needs separate specifications. Those specifications may need to address the animal or child involved, expected pressure, opening size, attachment method, corrosion exposure, terrain, gates, and inspection. Do not select mesh and fasteners solely because they are sold near the cedar components.

A documented garden project planned to add electric strands for deer deterrence, which shows only that its builder considered the open cedar rails insufficient by themselves. It does not prove that the same arrangement will control deer at another property.

Final buyer-verification list

Before paying or accepting delivery, verify:

• Actual cedar species
• Seller-defined grade and measurable dimensions
• Treatment status
• Ground-contact rating or intended post use
• Actual rail length
• Tenon shape and dimensions
• Mortise dimensions and orientation
• Installed center-to-center spacing
• Required line, end, corner, and gate posts
• Gate opening, post, hinge, and latch requirements
• Written installation instructions
• Warranty and exclusions
• Current availability and lead time
• Bundle or minimum-order quantities
• Freight, unloading, and delivery access
• Return and restocking terms
• Replacement availability for damaged or mismatched pieces

Frequently Asked Questions

How many posts and rails do I need for 100 feet of cedar split-rail fence?

It depends on the selected system’s actual center-to-center spacing and the number of rail levels.

As one documented example, Menards’ suggested 100-foot two-rail design lists 20 ten-foot rails, 9 line posts, and 2 end posts. That represents 10 sections and 11 total posts, but it is a retailer-specific suggested material list rather than a universal kit.

For another system, divide 100 feet by the manufacturer’s installed section spacing and round up for a preliminary section count. Then reconcile how the rigid components will physically fit, multiply the finalized sections by the number of rail levels, and begin with one more post than sections before adjusting for shared corners and gates.

How deep should cedar split-rail fence posts be set?

There is no single depth for every cedar split-rail fence. The reviewed guidance ranges from at least 18 inches for one 3.5-foot demonstration, to about 27 inches for one particular 6-foot-6-inch cedar post, to about 30 inches in another supplier’s system; two general guides recommend approximately one-third of the post.

Use the selected manufacturer’s instructions and applicable local requirements, accounting for frost depth, soil, drainage, terrain, fence height, wind, gate loads, and animal pressure. Distinguish burial depth from total hole depth when gravel is placed below the post.

Do cedar split-rail posts need concrete?

Not always, but concrete may be appropriate or required in some conditions. Several guides describe compacted soil or gravel and use gravel for drainage, while Home Depot says concrete may be needed depending on soil conditions.

The correct method depends on applicable rules, product instructions, post treatment or intended use, frost movement, drainage, soil stability, fence dimensions, and loads. Avoid blanket claims that concrete is always necessary, always damaging, or never appropriate.

Can a cedar split-rail fence contain dogs, small children, livestock, or deer?

An open split-rail fence generally cannot serve as a complete barrier for dogs, other small animals, or small children. Home Depot and Tractor Supply expressly identify this limitation.

Livestock and wildlife control also cannot be determined from rail count alone. A separately designed layer of mesh, woven wire, electric fencing, or another system may be needed. Obtain specifications appropriate to the animal, site, gates, terrain, and local requirements.

Can cedar rails and posts from different suppliers be mixed?

Do not assume so. Hoover Fence says the mortise and tenon dimensions are common across its own Pony, Standard, and Jumbo product grades, allowing compatibility within that seller’s system. That does not establish compatibility with another manufacturer.

Before mixing components, compare actual rail length, tenon dimensions, mortise size, post-hole orientation, intended center spacing, rail girth, species, and treatment status. Obtain confirmation from both suppliers.

The practical decision rule

Choose a cedar split-rail fence when an open, rustic boundary suits the property. Then select one compatible supplier system, calculate the project by actual sections, and price every post, rail, gate, accessory, and delivery charge.

Before digging, resolve boundaries, permits, utilities, drainage, frost depth, soil, and load conditions. If the project must contain animals or protect children, use the cedar rails as the visible framework and obtain separate, locally appropriate specifications for the actual containment barrier.