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Board On Board Fence
Quick answer: A board-on-board fence uses two staggered layers of pickets that overlap, so there are no see-through gaps even after wood shrinks. It gives full privacy and looks finished from both sides, but uses roughly a third more pickets than a side-by-side fence. Use our picket calculator with your board width and overlap to count boards.
How board-on-board works
In a standard side-by-side privacy fence, pickets butt edge to edge or with a small gap on one side of the rails. As boards dry they shrink, and gaps appear. Board-on-board solves this by fastening one layer of pickets with gaps slightly narrower than a picket, then fastening a second layer over the gaps so each board overlaps its neighbours by an inch or so on each edge. The result looks similar from both sides and stays private as boards move with the seasons.
Board count math
For side-by-side pickets: pickets = length in inches ÷ (picket width + gap). For board-on-board: pickets = length in inches ÷ (picket width − overlap per edge). With 5.5 in boards and a 1 in overlap, you need about 2.67 boards per foot, versus 2 boards per foot side-by-side with a 0.5 in gap. Over 100 ft that is roughly 267 versus 200 boards before waste. Try it in the fence picket calculator.
Pros and cons
| Pros | Cons |
|---|---|
| Full privacy even after shrinkage | About a third more pickets |
| Attractive on both sides ("good neighbour") | Heavier; posts and rails carry more load |
| Lets some air through the overlaps | More fasteners and labour |
| Works with any height bylaw allows | More surface area to stain |
Rails and posts for a heavier fence
More boards mean more weight and a solid face to the wind. Most board-on-board fences use three rails for 6 ft heights. Posts set to appropriate depth and spacing matter; see how deep fence posts and fence post spacing. Some builders reduce spacing to 6 ft in windy areas.
Layout tips
- Set and brace posts, then install rails level or racked to the slope.
- Cut a spacer block equal to the gap for the first layer (board width minus twice the overlap).
- Install the first layer, checking plumb every few boards.
- Install the second layer centred over each gap.
- Fasten with exterior-rated nails or screws compatible with treated lumber; two per rail per board is common.
- Keep pickets off the soil; a small gap at grade reduces rot.
Shadowbox versus board-on-board
Shadowbox fences alternate pickets on each side of the rails, creating a 3D look with more airflow but less privacy at angles. Board-on-board places both layers on the same side for tighter privacy. Count pickets similarly; the difference is mostly in look and wind.
Worked example
Figures below are illustrative examples (2026-10-29), not quotes or guarantees.
Assumptions: 80 ft of 6 ft board-on-board, 5.5 in cedar pickets, 1 in overlap, 10% waste, 8 ft spacing, three rails. Pickets: 960 in ÷ 4.5 = 213.3 → 235 with waste. Side-by-side with a 0.5 in gap would need 160 → 176 with waste. If each cedar picket cost $6, board-on-board adds 59 boards, about $354. Posts: 10 sections, 11 posts plus ends and corners as needed. Rails: 30 plus waste. Prices are invented examples.
Stain and finish
A board-on-board fence has more exposed edges and overlapping faces, so staining takes longer and uses more product. Many people stain pickets before installing them so overlapped edges are covered. Use the fence stain calculator and add extra for edges. See the fence stain guide for product types.
Costs relative to other styles
Board-on-board adds material cost (more boards and fasteners) and labour time. Compare against a standard privacy fence and a vinyl privacy system using wood fence cost and vinyl vs wood. If budget is tight, consider board-on-board only where privacy matters most, like along a patio.
Board-on-board on slopes
Because each board is fastened individually, board-on-board adapts well to racked slopes: rails follow the ground and pickets stay plumb, so the bottom edge tracks the grade. On stepped sections, the bottom of each step leaves a triangle you may want to close with a rot board or landscaping.
Wood movement and board choice
Boards shrink across their width as they dry, and swell again in wet weather. Freshly treated pine is often very wet when bought, so it may shrink noticeably over its first season. Cedar is usually drier and more stable. With board-on-board, the overlap absorbs that movement; with side-by-side, gaps open. Choose an overlap that still covers after expected shrinkage; 1 in per edge is common, but ask your yard about moisture content.
Fasteners and splitting
Nailing close to board ends can split cedar and dry pine. Pre-drilling or using fasteners designed for fence boards helps. Stainless or hot-dip galvanized fasteners resist corrosion from treated lumber chemicals and avoid black streaks on cedar. Two fasteners per rail per board help limit cupping.
Gates in a board-on-board fence
A board-on-board gate is heavy because it carries two layers of pickets. Build the gate frame from straight, dry lumber, add a diagonal brace running from the bottom hinge side up to the top latch side (so the brace is in compression), and consider a steel anti-sag cable kit. Hang it on an upsized, deeply set post. Leave consistent clearance at the latch side for seasonal swelling, and test the swing before fastening the second layer so you can adjust hinges while the gate is lighter.
Fastener choice
Use hot-dip galvanized or stainless fasteners rated for treated lumber. Cheap fasteners corrode and streak, and with two layers of boards you are buying twice as many, so count them in your budget.
FAQ
Is board-on-board the same as double-sided?
Effectively yes; it looks nearly the same from both sides.
How much overlap?
About 1 in per edge is common; follow your design and board width.
Is it allowed everywhere?
Style rarely matters to bylaws, but height does; see privacy fence height.
How many posts and rails?
Use the fence calculator.
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