Table of Contents
- Call 811 before digging, and mark post locations about 8 feet apart for standard panels.
- Dig below the local frost line and roughly three times the post width, with a gravel base for drainage.
- Plumb the post on two sides and brace it until the concrete cures; slope the top away from the post.
- Fast-setting concrete is convenient, but follow the bag's instructions and wait before hanging panels.
- Check fence height, property line and permit rules with your municipality or building before you dig.
A fence is only as good as its posts. Panels, boards and gates come and go, but the posts carry every load: wind pushing on a solid privacy fence, a gate swinging a hundred times a week, a kid hanging on the top rail. When a post is set badly, the whole fence leans within a season or two, and in New York, where frost heaves the ground every winter, a poorly set post fails faster than anywhere warmer.
This guide covers the job from layout through curing, with the choices that matter in this climate. It also covers alternatives to concrete, how to fix common mistakes and what rules to check in the city, on Long Island and in New Jersey. Information is current as of October 2026.
1. Plan the Fence Before You Dig
Good fences start on paper.
- Find the property line. Use a survey, deed or plot plan, not the existing fence, which may be off. Setting posts a few inches inside your line avoids disputes.
- Decide on height and style. Taller solid fences catch more wind and need deeper, stronger footings. Open fences such as picket or rail are easier.
- Choose the post material. Pressure-treated lumber rated for ground contact, cedar, steel and composite all work. Rated posts cost more but last longer in contact with soil.
- Choose post size. A 4-by-4 works for many residential fences up to about six feet when spacing is tight; taller or heavier fences and gate posts commonly use 6-by-6.
- Plan the spacing. Fence panels are usually eight feet long, so mark posts eight feet apart, center to center, or adjust to the panel width you buy.
- Plan the gates. Gate posts carry far more stress than line posts. They need larger sizes and deeper footings.
If you are replacing an existing fence, removing old posts comes first. Our guide to removing broken fence posts set in concrete covers three ways to get them out.
2. Rules, Utilities and Permits
Call 811
Contact the 811 utility-marking service before you dig, and wait for the lines to be marked. Hand-dig near marks. Utility lines often run along lot lines, right where fences go.
Height, location and permits
Rules vary by location. In New York City, check the Department of Buildings' page on how to obtain a permit and our permit checker, since some fences, retaining walls and structures need review. Long Island towns and villages, including those in Nassau County, have their own building departments; the Nassau County website is a starting point for county resources. In New Jersey, municipal construction offices handle permits.
Landmarks, co-ops and associations
If your home is in a landmark district, the Landmarks Preservation Commission may have a say over visible changes; check the LPC before starting. Co-ops, condos and homeowner associations often restrict fence heights, materials and colors.
Neighbors
A shared fence is a shared relationship. Talk to the neighbor before you start, agree on the line and who pays for what, and put it in writing if you can.
3. Tools and Materials
| Materials | Tools |
|---|---|
| Fence posts (ground-contact rated or steel) | Post-hole digger or auger |
| Fast-setting concrete mix (or standard mix) | Digging bar and shovel |
| Gravel (3/4-inch crushed stone works well) | Tape measure and string line |
| Wooden stakes or braces and screws | Level (4-foot is best) |
| Water | Wheelbarrow or bucket and hose |
| Exterior caulk or sealant (optional) | Tamper or the end of a 2-by-4 |
| Fence panels or rails and hardware | Safety glasses, gloves, dust mask |
Wear a dust mask or respirator when pouring dry concrete mix. The dust contains silica, which OSHA regulates; see its silica guidance. Wet the mix promptly and avoid shaking bags near your face.
4. The Step-by-Step Method
Step 1: Measure and mark the post holes
Stretch a string line along the fence run. Mark each post location with stakes or spray paint, about eight feet apart for standard panels. Check corners with a tape measure using the 3-4-5 method, or a framing square. Measure twice. Moving a post after the concrete sets is a major headache.
Step 2: Dig the post holes
Dig each hole about one third of the post's total length deep, and below the local frost line. In the New York area that is roughly three to four feet, but confirm with your municipality. As a rule of thumb, make the hole about three times the width of the post. For a 4-by-4, that is about ten to twelve inches. Taller fences, gates and sandy or loose soils need deeper and wider holes. Use an auger for many holes, a post-hole digger for a few, and a digging bar for roots and rocks.
Step 3: Add gravel to the base
Pour about six inches of gravel into each hole and tamp it. The gravel lets water drain from the base of the post, which is where wood rots first. Do not skip this step in heavy clay soils common in parts of the region.
Step 4: Position and brace the post
Stand the post in the hole on the gravel and check it with a level on two adjacent sides. Brace it with stakes and scrap lumber screwed to the post, so it holds plumb while you pour. For a long run, string a line between end posts and align the tops. Set corner and gate posts first, then fill in the line posts.
Step 5: Pour the dry concrete mix
Fast-setting concrete is popular for fence posts. Many products allow you to pour the dry mix into the hole around the post and then add water on top; others require mixing first. Read the bag and follow it. Pour to about three to four inches below ground level, leaving room for soil or a finish layer.
Step 6: Add water to the dry mix
If your product allows pouring dry, add water slowly according to the instructions, usually about a gallon or so per bag, and work it into the mix with a stick or rod to remove air pockets. Too much water weakens concrete; too little leaves dry pockets. If you accidentally add too much, see our guide on how to fix too much water in concrete.
Step 7: Fill and slope the top
Recheck plumb. Finish the top of the concrete with a trowel and slope it away from the post so water runs off. Backfill the remaining depth with soil, or leave the concrete exposed and seal it. Concrete that holds water against a wooden post causes rot.
Step 8 (optional): Seal the post
Run a bead of exterior-grade caulk or sealant where the post meets the concrete. This keeps water from entering the gap that forms as materials expand and contract. Reapply when it cracks.
Cure before loading
Even fast-setting products continue to gain strength. Leave the braces in place for the time the bag recommends, avoid attaching panels or gates until the concrete has set, and allow longer in cold or wet weather. Heavy loads, gates and tall solid panels deserve extra waiting time.
5. Alternatives to Setting Posts in Concrete
Concrete is not the only option, and in some cases it is not the best.
Gravel-only (dry-set) posts
Backfill the hole with compacted crushed stone in layers. Gravel drains freely, which helps wood last, and it lets you replace a post later without breaking concrete. The trade-off is less stiffness, especially for tall fences, gates or windy sites. Compaction and good soil make the difference.
Metal post anchors and brackets
Anchors, spikes or bolt-down brackets lift the post out of direct contact with soil or concrete, protecting wood from rot. They suit decks, patios and existing slabs, and can be installed on concrete or pavers with the right fasteners. They are not ideal for tall privacy fences or gates in open yards, where lateral loads are high. If your fence meets a painted patio, see our guide to painting concrete pavers in your NYC backyard, and mind the finish when drilling.
Steel posts
Galvanized or powder-coated steel posts are strong and do not rot. They are often set in concrete too, with a similar process.
Combination
Many installers use a gravel base, a concrete collar and sealed top. That gives drainage at the base and stiffness at the top.
6. Common Mistakes and How to Fix Them
| Mistake | What happens | Fix |
|---|---|---|
| Hole too shallow | Post leans or heaves in winter | Dig below frost line |
| No gravel base | Water sits at post base; rot | Add gravel before setting |
| Concrete too wet | Weak footing | Follow bag ratio; see the water guide |
| Not plumb | Crooked fence line | Brace and recheck during set time |
| Flat concrete top | Water pools at post | Slope away from post |
| Panels hung too soon | Leaning posts | Wait for full set |
| Ignoring utilities | Strike on a buried line | Call 811 every time |
| Wrong post material | Early rot | Use ground-contact rated or steel |
If a post has already set crooked, you can sometimes straighten it in the first hour. After that, the footing has to be removed and reset.
7. Finishing, Painting and Protecting the Fence
New wood needs time to dry before painting or staining; follow the lumber manufacturer's guidance. Pressure-treated wood often needs several weeks or months to dry enough for paint. Seal cut ends, because cut surfaces expose untreated wood. Coat all sides of the posts and rails, including the bottom edges, where moisture enters.
For exterior paint on fences, trim and siding, prep matters just as much as it does on a house. Our step-by-step guide to exterior painting and exterior painting guide for NYC, Long Island and NJ explain the process. If you are removing tile or flooring near an exterior door and need to deal with a concrete subfloor, our guide to removing tile from a concrete subfloor covers that side of concrete work.
8. Time, Cost and Planning
A weekend is a realistic timeline for a small fence, with a longer period if you wait for concrete to cure and wood to dry. Cost depends on length, height, post and panel materials, number of gates, access, soil and whether old fence removal is needed. For related work and broad planning ranges, see our renovation cost guide for NYC. For a firm number, rely on a written, itemized quote that separates removal, new footings, materials and finishing.
9. When a Licensed Team Makes Sense
Setting one or two posts is a fair DIY job. A whole fence line, a high privacy fence or a yard with tight access is another story.
Layout and boundaries. Errors in layout are the most expensive to fix. We verify lines against surveys, mark utilities, and coordinate with neighbors where needed.
Soil, slope and drainage. Clay, sand, fill, roots and slopes change how deep and wide footings should be. We adjust the design, and if drainage needs correction, we handle it before setting posts.
Permits and rules. We check what your municipality, co-op or landmark district requires and prepare paperwork. In New York City, residential remodeling requires a Home Improvement Contractor license, and N.Y. Renovation Services is fully licensed and insured.
Heavy work and cleanup. Digging, hauling concrete bags and removing debris are physical and messy. We bring the equipment, protect lawns and patios and remove spoil.
Coordinating with painting, patio and siding work. Fence posts are often part of a larger exterior update. We schedule the trades in order: demolition and posts first, then repairs, then painting, so nothing is splattered or damaged. See the siding cost estimator if your house walls need attention too.
Wind, gates and long-term stability. The posts that fail first are gate posts, corners and the ends of long runs, because they carry the most load. We size and deepen those footings accordingly, check plumb as the concrete sets and leave braces in place for the right time, so the fence still hangs true after its first winter and the first big nor'easter.
Access and protection. In a Brooklyn or Manhattan rear yard, everything arrives through the house or building. We plan the route, protect floors, stairs and elevators, schedule deliveries within your building's hours and keep concrete, spoil and tools away from neighbors' plantings and surfaces.
Records on paper. You receive a written scope that lists post sizes, depths, materials and finishes, which helps with association approvals, insurance questions and future repairs.
Clear, itemized pricing. Your written quote lists removal, footings, materials, finishing, permits and debris removal, with no hidden fees. At N.Y. Renovation Services, five percent of the project total is donated to a nonprofit of your choice.
Honest scope. Fence work is not our main focus; our core services are gut renovation, tile, flooring, interior and exterior painting. If your job is only fence posts, we will tell you whether it fits us or whether a fence specialist is a better match. For anything bigger on the exterior, request a free estimate.
10. Neighborhoods and ZIP Codes We Serve
N.Y. Renovation Services is based on Staten Island and works throughout the five boroughs, Long Island and nearby New Jersey. Fence conditions vary a lot across the region.
- Upper East Side (Manhattan), ZIPs 10021, 10028, 10065, 10075, 10128: pre-war co-ops, limestone townhouses and landmark districts. Rear gardens are reached through the house or building, with white-glove building rules, delivery windows and landmark review for visible changes.
- Cobble Hill (Brooklyn), ZIPs 11201, 11231: brownstones in the Cobble Hill Historic District. Narrow rear yards, shared fences and access through the house are typical; check landmark rules before changing visible fencing.
- Maspeth (Queens), ZIP 11378: two-family homes and industrial-adjacent lots. Security fencing, gates and taller fences are common, so footings and gate posts need to be robust.
- Port Richmond (Staten Island), ZIP 10302: older wood-frame homes and two-family houses. Older yards often have uneven grades and buried debris, so test-dig carefully.
- Long Beach (Nassau County, Long Island), ZIP 11561: barrier-island homes and condos in flood-zone elevation areas. Sandy soil, salt air and wind call for corrosion-resistant hardware, and flood rules may affect structures.
- Edgewater (Bergen County, NJ), ZIP 07020: waterfront high-rise condos. Fences are generally association matters, and work is often limited to terraces, patios and small private areas under building rules.
For general information about our work in Manhattan, see our Upper East Side restoration page.
11. Next Steps: Get Your Free Estimate
Here is a short path from idea to a straight, solid fence.
- Confirm the line and the rules with your municipality, co-op or neighbor.
- Call 811 and mark the area.
- Choose posts and spacing that match your fence style and height.
- Decide DIY or hired help based on the number of posts, gates and access.
- Request an itemized estimate if the job includes removal, a long run or other exterior work.
You can request a free estimate online, call (347) 455-1741 or text photos. We will visit, explain what we see and give you a written quote. If the fence is one piece of a bigger yard or exterior plan, tell us about the rest: painting, siding, a patio refresh or masonry repair. We would rather price the whole sequence once than have you pay for several separate mobilizations, and we will tell you plainly which pieces we do ourselves and which are better handled by a specialist.
N.Y. Renovation Services is open Monday through Saturday, 8 AM to 5 PM, and the estimate is free.
Safety Note: All work follows OSHA 30 safety and EPA Lead-Safe practices for pre-1978 homes. Check local permit requirements before starting.
James - Lead Renovation Editor. With over 20 years in renovation and construction, James writes and edits our guides. More about James