Decks & Fences Diagrams
9 diagrams · 3 calculators
Deck frame anatomy, joist span and spacing, ledger flashing, plus fence post depth, spacing and gate bracing — the structural diagrams for outdoor framing that lasts.
Calculators in this category
Decks & Fences · 9 diagrams
- Decks & Fences
How deep a fence post goes — below the frost line, on a gravel base, set in crowned concrete
A fence post needs more than a couple feet of concrete: dig below the frost line so it can’t heave, set the post on a 6″ gravel drainage base, and crown the concrete above grade to shed water. About ⅓ of the post is buried.
- Decks & Fences
Fence post spacing — 8 feet on-center maximum, measured center to center
Fence posts sit a maximum of 8 ft on-center because rails come in 8-ft lengths — and that span is measured center-to-center, not gap-to-gap. Sections = length ÷ 8 ft, rounded up; corner and end posts are heavier than line posts.
- Decks & Fences
Which way a fence gate brace goes — bottom hinge corner up to the top latch corner
The #1 gate mistake: a wood brace only works in compression. Run it from the bottom hinge corner up to the top latch corner so the weight loads into the bottom hinge. Run it the other way and the brace is in tension — the gate sags and won’t latch.
- Decks & Fences
Parts of a deck frame — how load travels from the decking down to the footings
How a deck carries its load to the ground: decking → joists → the ledger (at the house) and the beam → posts → footings below the frost line. The joist can cantilever past the beam up to about ¼ of its span.
- Decks & Fences
Deck joist span vs. spacing — how far each joist size reaches at 16″ and 24″ on-center
Span and spacing are different measurements: spacing is center-to-center across the joists; span is how far each joist reaches from ledger to beam. A bigger joist — or tighter spacing — spans farther (IRC R507.6, Southern Pine #2).
- Decks & Fences
Deck ledger flashing and lateral connection — how to attach a deck so it cannot rot or pull off
A rotted or under-fastened ledger is the #1 cause of deck collapses. Flash it in order — membrane behind the ledger, ledger through-bolted to the band joist, then cap flashing tucked behind the house wrap so each layer laps the one below — and add the lateral ties that resist pull-off.
- Decks & Fences
Deck stain opacity — clear to solid, and the grain-versus-protection trade-off
Picking a deck stain is really picking opacity, and opacity is a trade-off. Clear and semi-transparent stains show the wood grain but fade in ~1–3 years; semi-solid and solid stains hide more grain but carry the most UV pigment, so they last ~3–5 years between recoats.
- Decks & Fences
Why a gallon of deck stain covers less than the label says — wood, age, and texture
The label coverage rate is only the best case — new, smooth wood. Real coverage = label rate ÷ (surface texture × wood condition). Weathered gray wood and rough-sawn boards drink far more; a previously stained maintenance coat covers more. A second coat covers ~2× the first.
- Decks & Fences
A deck is more than its floor — railings, stairs, posts, and the underside all add up
The floor is only the start. A spindled railing coats every side of every baluster (~1.8× its face), stairs add a tread plus a riser per step, posts get all four sides, and staining the underside + joists roughly doubles the floor. Measure only the floor and you under-buy.