A horizontal wood fence panel with open gaps against garden planting.
Architectural visualization. It does not set privacy, spacing, support, hardware or local approval requirements.A narrow gap is still an opening, and its effect changes with viewpoint. Define privacy by the activity and viewing direction you want to screen. Then compare layouts with a simple physical mockup rather than relying on a photograph taken straight on.
Map the sensitive views
List the places where privacy matters: a dining chair, a kitchen window, a garden work area or the approach to a door. Draw lines toward the nearby path, driveway or neighboring windows. Changes in ground level can make the view over a fence more important than the view through it. Mark those conditions separately. A taller-looking photograph cannot establish whether a proposed arrangement screens your actual seating position.
Compare gaps at useful angles
Place several sample boards at the proposed separation and view them straight on and obliquely. Repeat with light behind the mockup. An offset or overlapping arrangement can change the view through the assembly, but it also changes its thickness, material quantity and access for cleaning. Record the configuration precisely rather than calling it simply a privacy fence. Confirm that the installer can reproduce the corner and gate transitions as drawn.
Document an achievable expectation
Describe the intended outcome in plain language, such as reducing direct views from the side path into the seating area. Avoid promising complete concealment under every condition. Wood changes dimension with moisture, so an installation gap is not a permanent optical measurement. Keep the sample decision, actual board width and installer-selected movement allowance together. If a later product change alters the face width, repeat the view test before approving the new layout.
Start with the view you want to interrupt
A privacy fence is a barrier between two positions. The relevant question is not simply how much of its elevation is wood. It is whether someone on a particular path can see a particular part of the garden. A seated person on a patio, a person standing at a neighboring window and someone walking along the sidewalk have different sightlines through the same fence.
Draw those positions on a small site plan. Include ground levels and the places people actually use: the dining table, a bedroom window, the outdoor shower or a service area. Then look in both directions. A fence that screens a seated patio from the street can still leave a clear view from an elevated neighboring deck. Adding height without considering that geometry can create a heavier boundary without solving the problem.
Coverage is a useful calculation, with a narrow meaning
For a repeating arrangement of equal-width boards and equal gaps, face-on board coverage is board width divided by board width plus gap. Using an illustrative 5½-inch board face, a ¼-inch gap gives about 95.7% coverage; a ¾-inch gap gives 88%; a 1½-inch gap gives about 78.6%. These figures describe the repeating pattern. A finite fence also has ends, posts, gates and changes of level.
| Illustrative gap | Repeating face-on coverage | What the number leaves out |
|---|---|---|
| ¼ inch | 95.7% | Viewing angle, board thickness and the observer's height |
| ¾ inch | 88.0% | Whether an opening aligns with a sensitive view |
| 1½ inches | 78.6% | Lighting, movement and visibility through multiple openings |
Coverage is not a privacy rating. At an oblique angle, the board edges and their thickness can obstruct a view that appears open face-on. Board direction matters because a lateral change in viewpoint interacts differently with vertical slots and horizontal slots. The Sightline guide and its controls make that distinction visible; a site mockup is still needed for the actual viewing positions.
Check privacy after dark, too
Daylight can make the darker side of a boundary difficult to see. At night, a brightly lit patio behind a darker fence may reveal more activity. Check the lighting arrangement rather than assuming a daytime sample settles the question. Temporary boards held safely in a proposed alignment can show whether the pattern conceals faces, movement or only broad shapes.
Keep the selected gap separate from the installation allowance. Wood changes dimension with moisture, and the initial spacing must suit the supplied boards and project detail. The USDA Wood Handbook's moisture chapter explains that dimensional behavior; it does not establish a universal fence gap. Write down both the intended visual result and the installation basis so one is not mistaken for the other.
Evidence & scope
General wood moisture behavior only; no species-specific movement allowance.
Original planning guidance. References support their stated technical scope; examples and workflows do not establish product approval.