Fence Building Tools: Everything From Posts to Finish

Layout and Marking

Before you dig a single hole, mark the fence line precisely. A string line between corner stakes defines the path. Drive stakes at each corner and gate post location, then run mason's line between them. Mason's line ($5 to $8 for a 500-foot roll) is preferred over regular string because it does not stretch or sag. A line level ($3 to $5) on the string checks for consistent height if you want the fence to follow a level line rather than the ground contour.

Mark each post location along the string. Standard post spacing is 8 feet on center for most residential fences, which works with standard 8-foot rail lengths. For 6-foot fences using 2x4 rails, 8-foot spacing is the maximum before rails start to sag under picket weight. Some builders prefer 6-foot spacing for a stiffer fence, especially in high-wind areas.

Measure from corner to corner and adjust spacing so you do not end up with an awkward short section at the end. If your total run is 52 feet, seven sections at 7.4 feet each looks better than six sections at 8 feet plus one at 4 feet. Spray paint or landscape flags mark each post hole location on the ground. Call 811 (the national utility locate line) at least 48 hours before digging to have underground lines marked.

A 100-foot tape measure ($15 to $25) is necessary for layout. A 25-foot tape works for individual sections but not for running the full fence line. Battery-powered laser levels ($50 to $150) project a reference line across long distances, which helps on uneven terrain where a string line is hard to read.

Post Holes and Setting

Post holes need to be about 3 times the width of the post and one-third the length of the post deep, plus 6 inches for gravel at the bottom. For a 6-foot fence with 8-foot posts (4x4 lumber), that means about 10 to 12 inches in diameter and 30 inches deep. A two-person post hole digger (clamshell type, $30 to $45) works for a few holes in loose soil. For more than about 10 holes, or for hard clay or rocky ground, rent a two-person gas auger ($50 to $80 per half day). It cuts the work from hours to minutes.

One-person electric augers like the XtremepowerUS 1500W ($150 to $200) handle light-to-moderate soil but stall in heavy clay or rocky conditions. They are practical if you have 10 to 20 holes and reasonably cooperative soil. For rocky ground, a digging bar ($20 to $30) breaks up rocks that the auger cannot get through.

Drop 6 inches of gravel in each hole for drainage, set the post, and check plumb with a post level. Post levels ($8 to $15) strap to the post with rubber bands or magnets so your hands are free to brace and adjust. The Johnson Level 175-O and Empire 340-2 are both reliable options. Check plumb on two adjacent faces simultaneously.

Fill with concrete. Fast-setting concrete mix like Quikrete Fast-Setting ($5 to $7 per 50-pound bag) does not need water premixed. Pour it in dry around the post, add water to the hole, and it sets in about 30 minutes. Each post hole typically requires 2 to 3 bags. Brace each post with angled 2x4s staked to the ground until the concrete fully cures. Check plumb one more time before you walk away from each post.

Rails and Pickets

After the concrete cures (at least 24 hours for standard mix, 4 hours for fast-set), attach the horizontal rails. Use two rails for a 4-foot fence and three for a 6-foot fence. A cordless drill or impact driver with structural screws, or a framing nailer with galvanized nails, handles the fastening. GRK RSS or SPAX PowerLags ($12 to $18 per box of 50) are popular structural screws for rail-to-post connections.

Toe-screw the rails directly into the post faces, or use metal rail brackets (Simpson Strong-Tie FB24 or FB26, $2 to $3 each) for a stronger connection. Brackets are especially important for the bottom rail, which takes the most stress from wind loading. Position the top rail with its top edge 6 to 8 inches below the top of the post. The bottom rail sits 6 to 8 inches above grade.

Pickets go on the rails with a consistent gap between them. A spacer block cut to the desired gap width (typically a quarter inch to three-eighths inch for privacy fencing) speeds the work and keeps everything uniform. An impact driver with exterior-rated screws is faster and more secure than nails for picket attachment. Two screws per rail per picket means six screws per picket on a 6-foot fence with three rails.

A string line across the top of the pickets keeps the tops even. Snap the line at the desired height, then align each picket as you attach it. For dog-ear or flat-top pickets, the top of each picket should touch the string. A circular saw trims pickets to length if your posts are not perfectly level, which they rarely are on sloped or uneven ground.

Gates

Gates are the trickiest part of a fence because they move and carry their own weight. A gate that works perfectly on day one can sag within a year if the frame is not properly braced. Build the gate frame from the same lumber as the fence, but add a diagonal brace from the bottom hinge side to the top latch side. This brace prevents sagging by transferring the gate's weight diagonally back to the hinged post. Without it, every gate eventually droops and drags on the ground.

Gate hinges need to be heavy-duty. Do not use the lightweight 3-inch hinges from the general hardware aisle. Use strap hinges or T-hinges rated for the gate weight. For a standard 3-foot wide, 6-foot tall privacy gate weighing 40 to 60 pounds, hinges rated for at least 75 pounds each are appropriate. The National Hardware N129-726 heavy-duty T-hinge ($8 to $12 per pair) and Everbilt 8-inch strap hinges ($10 to $15 per pair) are commonly used.

A drill and lag screws (3/8 inch by 3 inches, $0.50 to $1 each) attach the hinges to the post. Pre-drill pilot holes to prevent splitting the post. A self-closing spring hinge ($15 to $25) is worth considering for gates that provide pool access (often required by code) or gates that children leave open. Gate latches range from simple thumb latches ($8 to $15) to lockable options ($15 to $30). Match the latch style to how the gate will be used.

Leave a half-inch gap between the gate frame and the posts on each side to allow for wood expansion in wet weather. A gate that fits perfectly in dry conditions will bind and stick after rain if there is no clearance. For double gates, a drop rod ($10 to $15) holds the stationary gate panel in place.

Finishing

Unfinished wood fences weather to gray within a year or two. If you want to preserve the original wood color, apply a stain or sealant within a few weeks of building. New pressure-treated lumber should dry for 2 to 4 weeks before staining, as the treatment chemicals can prevent stain adhesion. Sprinkle water on the wood surface: if it beads up, the wood is not ready for stain. If it soaks in, it is ready.

A pump sprayer ($20 to $40 for a 2-gallon model) is the fastest application method for fences. It covers large areas quickly and gets stain into the gaps between pickets. A roller works on flat surfaces but misses the gaps. Brushes get full coverage but take 3 to 4 times longer than spraying on a long fence.

Back-brush after spraying to work the finish into the wood grain and catch drips. Use a 4-inch stain brush ($8 to $12) for back-brushing. Stain both sides of the fence if possible. Moisture enters from both directions, and finishing only one side can cause the boards to cup and warp. Let the stain dry for at least 24 hours before leaning anything against the fence.

Manufacturer specs for popular fence stains like Cabot Australian Timber Oil ($35 to $45 per gallon), Ready Seal ($30 to $40 per gallon), and TWP 1500 ($40 to $50 per gallon) recommend reapplication every 2 to 3 years for transparent stains and 3 to 5 years for semi-transparent. Coverage rates average 150 to 300 square feet per gallon depending on wood porosity. For a 100-linear-foot, 6-foot-tall fence (both sides), plan on 8 to 12 gallons.

Frequently Asked Questions

How Deep Should Fence Posts Be?

One-third of the total post length should be underground. For a 6-foot fence using 8-foot posts, that means about 24 to 30 inches deep. In areas with frost, posts should extend below the frost line to prevent heaving. Frost line depth varies by region: 12 inches in the southern U.S., up to 48 inches or more in northern states and Canada. Your local building department can tell you the frost line depth for your area. Add 6 inches of gravel at the bottom of each hole for drainage regardless of depth.

Should I Use Concrete or Gravel to Set Fence Posts?

Concrete is stronger and more stable, which matters for gate posts, corner posts, and end posts that take lateral force. Gravel provides drainage and allows post replacement later without breaking out concrete. A common approach is concrete for high-stress posts and gravel for straight-run line posts. In wet soil or areas with poor drainage, gravel can actually last longer because concrete can trap moisture against the post base, accelerating rot at the ground line.

How Long Does It Take to Build a Fence?

For a 100-linear-foot privacy fence, plan on 2 to 3 full days with a helper. Day one: layout, dig holes, set posts. Day two: rails and pickets. Day three: gate, trim details, and stain. Solo work roughly doubles the timeline. The biggest variable is hole digging. Rocky or clay soil can triple the time for that phase compared to sandy soil. Renting a power auger for a half day is one of the best time investments you can make on a fence project. See our borrow-or-buy guides for more on rental decisions.

Related Reading

• Concrete Finishing Guide
• Patio Paver Tools