A garden fence with concrete posts goes up in five stages: layout, dig, set gravel, pour concrete, plumb and brace, then fix panels after cure.
Building a neat boundary that stays put starts with a plan and steady steps. This guide walks you from first string line to the last panel. You’ll see the tools, the layout, the digging rhythm, and the way to mix and pour so posts stay plumb.
Setting A Garden Fence On Concrete Posts: Step-By-Step
Here’s the road map you’ll follow. First, mark property lines and call your local utility-marking service before any digging. In the U.S., use Call 811 to get lines marked. Next, set your layout with string and stakes, dig the holes, drop in compacted gravel, and set each post in concrete. Keep each post level while the mix sets, then hang rails or panels once the base has cured.
Tools And Materials
- Tape measure, bright twine, stakes, and line level or laser
- Post hole digger or auger; spade and trenching shovel
- Wheelbarrow and mixing tub (unless you’re using no-mix fast-set)
- Spirit level (600 mm or longer) and post level
- Timber braces and screws for temporary bracing
- Drainage gravel (10–20 mm clean stone)
- Fast-setting or standard concrete mix; water source
- Concrete posts and fence panels or rails with fixings
- Rubber mallet, saw for gravel boards, PPE (gloves, boots, eye protection)
Plan Your Spans And Post Positions
Measure the total run. Most garden panels are 6 ft wide (about 1.83 m), so plan centers at panel width plus post thickness if you’re using slotted posts. Keep a consistent rhythm along the line; small gaps at the end look better than one oversized panel in the middle. Add a gravel board if you’re keeping timber off damp soil.
Quick Sizing Guide And Mix Picks
Use this compact table to pick a hole depth and a rough bag count per hole based on typical 6 in (150 mm) post diameters and common panel heights. Adjust for soft ground, high wind, slopes, and larger posts.
| Fence Height | Hole Depth* | Fast-Set Bags/Hole** |
|---|---|---|
| 4 ft (1.2 m) | 18–24 in (450–600 mm) | 2–3 |
| 5 ft (1.5 m) | 24–30 in (600–750 mm) | 3–4 |
| 6 ft (1.8 m) | 30–36 in (750–900 mm) | 4–5 |
| 7 ft (2.1 m) | 36–42 in (900–1050 mm) | 5–6 |
| 8 ft (2.4 m) | 42–48 in (1050–1200 mm) | 6–7 |
*A common rule is to bury roughly one-third of total post length. **Bag counts assume 50-lb (22.7 kg) fast-setting mix and a bell-shaped hole. Use a calculator from a mix maker such as QUIKRETE instructions to refine the number.
Site Checks Before You Dig
Property Lines And Permissions
Confirm the boundary on your deed or survey. Talk with neighbors if the line is shared. Local rules may set max height, required setbacks, or style limits. Permits vary by region, so read your local planning page.
Underground Services
Book a locate so buried lines are marked; dig by hand near marks and keep outside the tolerance zone.
Layout That Keeps Panels Straight
Drive a stake at each end of the run. Stretch a tight mason line at the finished face of the posts. Set the line height to the top of the gravel board or the lower rail. Check sightlines from multiple angles so the run reads straight from the house and the street.
Mark Center Points
From the first corner, mark centers for each post. Use spray paint on turf or a marker on hard ground. If the last bay is short, split the difference across the last two bays so the eye reads a balanced run.
Digging Holes With The Right Shape
Cut a neat plug of turf first and save it to finish the hole later. Dig to the target depth and widen the bottom by a couple of inches to make a “bell” that locks the footing. Keep the top lip just wider than the post so you can pack soil tight later.
Add A Free-Draining Base
Drop in 4–6 in (100–150 mm) of clean stone and tamp it until it’s firm. This bed drains water away from the post and resists frost heave.
Set, Plumb, And Brace Each Post
Place the post in the hole. Align the slot or face to the string line. Use a post level on two sides and adjust until it’s plumb. Screw temporary braces from post to stakes at two directions so nothing moves during the pour.
Choose Your Mix Method
Fast-setting no-mix: Tip dry mix into the hole, then add the labeled amount of water on top. This method is handy when you need speed. The product page linked above lists water and set times for common bags.
Standard mix: Blend cement, sand, and aggregate with water until you reach a peanut-butter-like slump. Fill the hole in lifts and rod the mix so air escapes.
Pour And Shape The Crown
Keep the post steady and fill the hole to 2–3 in (50–75 mm) below grade. Trowel a gentle dome sloping away from the post so rain sheds. Re-check plumb from two directions. Adjust braces until it’s dead straight to the string.
Set Time And Cure Tips
Fast-set mixes grab in 20–40 minutes under mild weather. Don’t load panels until the product’s stated set window passes. Standard mixes take longer; light work can resume after a day, and full strength builds over about 28 days. Keep the top damp with a light mist in dry, hot spells.
Spacing Rails Or Dropping In Panels
Once bases have set, add rails or slide in panels. Keep a steady gap off the ground to clear splash-back and mulch. Use stainless or exterior-rated fixings, and add caps to seal the post tops.
Work The Slope
On a gentle slope, step panels and keep tops level. On a long grade, rake boards to follow the ground while holding a constant top line. Check gate swing clearance before you fix hinges.
Wind, Frost, And Soft Ground Adjustments
In gusty areas or sandy soil, deepen holes and increase diameter. Add more gravel at the base. Where frost is an issue, keep the footing below the local frost line and form a clean bell so the base locks to undisturbed soil.
Drainage And Rot Control
Concrete posts don’t rot, but panels and rails still need airflow. Keep timber clear of soil with a gravel board. Seal cut ends with a wood preservative. Keep sprinklers from soaking panels day after day.
Quality Checks As You Go
- Faces track the string with no gaps
- Posts read plumb on two sides
- Crowns shed water away
- Gate posts set deeper with extra bracing
Common Mistakes To Avoid
Shallow Holes
Too little embedment makes lean and twist likely. Use the one-third rule and go deeper in poor soil.
No Gravel Base
Skipping stone leaves water trapped at the footing. A simple 4–6 in bed handles drainage and helps resist movement.
Dry Mix, No Water
Some builders sprinkle and walk away. Dry powder needs the labeled water to hydrate. Follow the bag for water per hole.
Not Bracing
Even a small nudge can move a fresh footing. Two braces per post keep faces on the line while the mix grabs.
Panels And Hardware
Match the panel to your goals. Solid boards add privacy but weigh more, so deepen footings at gate posts. Picket or featheredge runs are lighter and handle slopes neatly. Use exterior-rated screws, anti-rattle clips for slotted posts, and caps on post tops.
Safety And Setup Notes
- Wear gloves, safety glasses, and boots
- Lift bags with a straight back or split loads into buckets
- Keep kids and pets away from open holes
- Rinse tools before mix hardens
Post And Concrete Troubleshooting
Use this table to fix common on-site hiccups. Keep a driver drill, spare braces, and a small bag of mix on hand for quick saves.
| Problem | Likely Cause | Fast Fix |
|---|---|---|
| Post drifts out of plumb | Braces too light or bumped | Re-square, add a third brace, pack fresh mix |
| Water pools at post | Flat crown or low grade | Shape a steeper dome; add soil and re-grade |
| Panel rattles | Loose clips or uneven slots | Shim with wedges; fit anti-rattle clips |
| Gate sags | Hinge post too shallow | Longer hinge screws; diagonal brace; deeper base on rebuild |
Care Tips After The Build
Once the fence is up, walk the line each season. Tighten hardware, check crowns, and clear soil away from any timber. Wash off fertilizer splash that hits panels. Oil or stain wood on a dry day for longer life.
Quick Reference: Core Steps
- Confirm boundary, permits, and book utilities
- Lay out the run with a tight mason line
- Mark centers and dig bell-shaped holes
- Drop in and tamp 4–6 in of gravel
- Set the post, plumb, and brace
- Pour concrete, dome the top, and re-check plumb
- Let the base set, then fit panels or rails
- Seal exposed wood and add caps
Source notes: Mix makers publish water and set times for their products; see the QUIKRETE post guide. In the U.S., utility locating is free through 811. Check your local rules for frost depth, height limits, and setbacks.