The Homeowner's Guide to Decks & Patios

Wood and composite are fundamentally different products with different maintenance requirements, failure modes, and lifespans.

Wood and composite are fundamentally different products. Understanding which you have — and what it needs — is the starting point for every maintenance and repair decision.

Pressure-treated wood

The most common decking material. Cost-effective, structurally sound, and widely available. The treatment protects against rot and insects but not against weathering — untreated pressure-treated wood will crack, check, and gray over time. Annual cleaning and sealing or staining is required to maintain appearance and slow weathering. The structural components (joists, beams, posts) are almost always pressure-treated regardless of what decking surface is used.

Cedar and redwood

Naturally rot-resistant and dimensionally stable. They look better than pressure-treated wood when maintained but require the same sealing and staining schedule. Significantly more expensive than pressure-treated but worth it for the appearance and natural stability.

Composite decking

Manufactured from wood fiber and plastic. Requires no sealing or staining, resists moisture and insects, and maintains its appearance with minimal maintenance. The tradeoff is cost — composite is typically 2-3x the material cost of pressure-treated wood. Early composite products had significant mold and moisture problems; current-generation products are substantially better but not maintenance-free. The structure beneath composite decking is still pressure-treated wood.

PVC decking

All-plastic with no wood fiber content. The most moisture-resistant option and won't support mold growth. The most expensive option and can feel less solid underfoot than wood or composite. Best suited for high-moisture environments where wood deterioration is a serious concern.

A deck is a structural system. Every connection point is a potential failure point.

The ledger

The board that connects the deck to the house. It's the most structurally critical component and the most common source of deck collapses. The ledger must be through-bolted to the house framing — not nailed — and must have flashing to prevent water intrusion behind it. Improper ledger connections are responsible for the majority of deck structural failures.

Posts and footings

Posts must bear on concrete footings that extend below the frost line — footings that don't go deep enough heave in freeze/thaw cycles, causing the deck to move and connections to loosen over time. Post bases that allow air circulation under the post extend post life significantly compared to direct burial.

Joists and beams

The horizontal framing members hidden under the decking surface. Joist deterioration is one of the most common problems homeowners miss because it's invisible from above. Any soft spots when walking on the deck indicate joist problems below. These should be inspected from underneath at least every few years.

Railings and balusters

A safety system, not just an aesthetic element. Building code requires railings on decks 30 inches or more above grade. Railing connections to posts and the deck frame are high-stress points that deteriorate over time. A railing that flexes or feels loose when pushed is a safety hazard that needs immediate attention.

What happens to a wood deck over time — and when each type of problem typically appears.

Wood deck deterioration progression

What to check yourself annually and what a professional deck inspection should cover.

A thorough annual deck inspection takes about 20 minutes and can catch problems that become major repairs if left unaddressed. Do it in spring after winter, when any freeze/thaw damage will be most visible.

Walk the surface

Feel for soft spots — any flex or give underfoot that differs from the rest of the deck indicates a problem below. Look for popped fasteners, cracked or split boards, and any boards that feel spongy when pressed. Check railing connections by applying firm lateral pressure — any movement is a safety concern.

Check the ledger

From below the deck, look for signs of water damage behind the ledger flashing, rot at the ledger itself, and whether the ledger is through-bolted or only nailed. Nailed-only ledgers should be evaluated by a contractor for structural adequacy.

Get under the deck

This is where most problems hide. Bring a flashlight and a screwdriver. Press the tip into joists, beams, and posts. Sound wood resists penetration. Deteriorated wood allows the screwdriver to penetrate easily. Check posts at ground level — wood deteriorates from the bottom up and the damage is often not visible from above.

What a qualified deck contractor looks like and what to confirm before any structural work.

Deck construction and repair falls under general contracting in most states. Licensing requirements vary significantly — verify that any contractor you hire carries general liability insurance and workers' compensation, and check whether your state requires a specific license for deck work.

The permit conversation

Any contractor who suggests skipping a permit on structural deck work is creating a liability problem for you. Permitted work is inspected by your local building department. Unpermitted structural work has no independent verification and creates complications at sale. Pull the permit.