Ask any contractor what the biggest shift in backyard building has been over the past two decades and most will point to one thing: plank composite decking has largely replaced pressure-treated wood on quality projects. These engineered boards blend recycled wood fibers with plastic to give you the look of lumber without the annual sanding, staining, and splinter-picking. I’ve torn out plenty of gray, cupped, 12-year-old pine decks and replaced them with composite that will still look sharp when the homeowner sells the house. If you’re weighing a new deck or resurfacing an old one, here’s what you actually need to know.
Part of our Decks & Outdoor guide — explore the full guide →
What Composite Decking Is Made Of
Composite boards combine wood flour or fiber with polyethylene or polypropylene plastic, plus binders, UV inhibitors, and color pigment. There are two broad families. Uncapped composite is the older style, solid all the way through. Capped composite, which dominates the market now, wraps a durable polymer shell around the core on three or four sides, which is what gives modern boards their stain and fade resistance. When someone says composite today, they almost always mean the capped kind.
A newer cousin, capped polymer or PVC decking, drops the wood fiber entirely for even lighter weight and better moisture resistance, though it costs more and can feel less like real wood underfoot.
Board Sizes and Profiles
Understanding board dimensions helps you order correctly and avoid waste. Standard plank composite decking comes in these common sizes:
- Width: Nearly always a nominal 6″, actually about 5.5″ wide, to mimic a standard deck board.
- Thickness: 1″ nominal (about 0.94″) for full boards, plus thinner 1/2″ “cladding” or fascia boards for skirting and riser faces.
- Length: 12′, 16′, and 20′ are standard. Buying 16-footers for a 15-foot run wastes little; matching length to your deck’s dimensions cuts waste and seams.
Boards also come in two edge styles. Grooved-edge boards accept hidden fasteners that clip into the groove between planks, leaving a fastener-free surface. Square-edge (solid) boards get screwed down through the face and are used for the perimeter row and stair treads where a hidden clip has nothing to grab.
The Major Brands
Three names come up on nearly every job, and each offers good, better, and best tiers.
Trex
The brand most homeowners know by name. Lines run from the entry-level Enhance up through Transcend and the premium Signature. Widely stocked, strong warranty, and a huge color range.
TimberTech (AZEK)
Known for its capped polymer PVC lines, which are among the most fade- and stain-resistant boards you can buy, plus capped composite lines at lower price points. Beautiful, realistic grain.
Fiberon
Excellent value with lines like Good Life, Concordia, and Sanctuary. Often a bit cheaper than Trex for comparable performance, and my go-to when a client wants premium looks on a working budget.
Other solid options include Deckorators and MoistureShield, the latter worth a look if your deck sits low to wet ground since it can be fully ground-contact rated.
What It Costs
Composite is not cheap, and being straight about that saves surprises. Here’s the range per linear foot for the boards alone:
- Entry capped composite: $2.50 to $4.50 per linear foot (Trex Enhance, Fiberon Good Life).
- Mid-tier composite: $4.50 to $7.00 per linear foot (Trex Transcend, TimberTech Prime+).
- Premium capped polymer/PVC: $7.00 to $12.00-plus per linear foot (TimberTech AZEK, Trex Signature).
For a 16-by-20 deck (320 square feet) you’ll need roughly 640 linear feet of 5.5″ boards. At a mid-tier $5.50 per foot that’s about $3,500 in decking alone, before hidden fasteners (add $0.40 to $0.80 per square foot), fascia, framing, and labor. Composite typically runs two to three times the material cost of pressure-treated pine, but you never buy stain again.
Gap Spacing and Expansion
This is where DIYers get burned. Composite expands and contracts with temperature more than wood does, mostly along its length, so you must leave gaps. Follow the manufacturer’s spec sheet, but typical numbers look like this:
- Side-to-side gap: hidden fasteners set this automatically, usually about 1/4″. Do not butt boards tight.
- End-to-end gap: 1/8″ to 3/16″ between board ends, wider if you install on a cold day since the boards will grow in summer heat.
- Board-to-house gap: leave 1/4″ between decking and any fixed wall or post.
Ignore these and you’ll get buckling on the first 95-degree afternoon. Cut and dry-fit end joints over a doubled joist so both board ends land on solid framing.
Framing Requirements
Composite is heavier and slightly more flexible than lumber, so the substructure matters. Space your joists no more than 16″ on center for standard perpendicular installation, and tighten that to 12″ on center for a diagonal (45-degree) board pattern, which spans a longer distance between joists. Stair treads need blocking so board ends and the front edge are fully supported. Skimp on framing and even the best board will feel bouncy and can sag between joists over time.
Installation Basics
Here’s the sequence I follow on a composite deck:
- Build a solid, properly spaced frame with joist tape over every joist top to protect the wood from trapped water.
- Start with a square-edge starter board at the house, face-screwed with color-matched composite screws.
- Clip grooved boards to each joist with hidden fasteners, keeping the automatic gap consistent.
- Stagger end joints so they don’t line up row to row, and land every joint on framing.
- Finish the perimeter with a square-edge picture-frame border and wrap the rim joist in fascia for a clean edge.
Predrill and countersink any face screws near board ends to avoid mushrooming, and use screws made for composite so the material caps cleanly around the head.
Color, Texture, and Style Choices
Modern boards come in an enormous color range, from warm honey and cedar tones to cool grays and deep espresso browns. Two features drive the realistic look. The first is variegated streaking, where the pigment runs in irregular bands to mimic real wood grain rather than a flat monotone. The second is embossed or wire-brushed texture pressed into the cap. Premium lines use a longer, less-repeating grain pattern so you don’t see the same knot repeat every few boards. If you’re building in full sun, lean toward lighter colors; dark boards absorb heat and can get uncomfortably hot on bare feet on a July afternoon.
You can also mix colors deliberately. A picture-frame border in a contrasting tone, or an inlaid stripe running down the deck, breaks up a large field and hides the perimeter cut edges at the same time.
Maintenance and Cleaning
Low-maintenance does not mean no-maintenance. Composite still needs an occasional cleaning to look its best. A couple of times a year, sweep off leaves and debris, then wash the boards with warm soapy water and a soft-bristle brush, working along the grain. Rinse thoroughly. For ground-in dirt or the light surface mold that shows up in shady, damp spots, a composite deck cleaner or a diluted oxygen-bleach solution clears it. Avoid pressure washing on a high setting, which can etch the cap and void some warranties; if you do use a pressure washer, keep it under 1,500 PSI with a fan tip held well back. Grease from a grill should be wiped up promptly, since even capped boards can stain if oil sits for days.
Is Composite Worth It
For most homeowners, yes. Plank composite decking costs more upfront, but you trade a weekend of staining every couple of years and a deck that grays out for one that holds its color and needs nothing but a hose-down and the occasional soapy scrub. Pick a capped board from a major brand, frame it tight, respect the gap spacing, and you’ll have a deck that looks great and holds up for 25 years or more. That’s a trade most people are glad they made the first hot summer they get to skip the sanding.
