# Composite Deck Material: Capped vs. Uncapped vs. PVC

Canonical URL: https://www.simplywise.com/blog/composite-deck-materials/
Plain text: https://www.simplywise.com/blog/composite-deck-materials/llms.txt
Publisher: SimplyWise, Inc. (https://www.simplywise.com)
Published: October 21, 2026
Updated: October 21, 2026
Category: Project Cost Guides
Summary: Composite deck material compared: capped and uncapped composite vs. PVC, hidden fastener and railing prices from retailers, and joist spacing specs.

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## Composite Deck Material: Capped vs. Uncapped vs. PVC Compared

Composite deck material comes in three builds: uncapped, capped, and PVC. Here is how they differ, what hidden fasteners and railing cost, and the joist spacing the makers require.

Composite deck material, at a glance

1. Composite splits into three builds: uncapped, capped, and PVC. Capped wraps the core in a plastic shell; PVC has no wood fiber at all.
2. Trex and TimberTech both confirm 16 inches on center as the standard joist spacing for a straight composite lay.
3. Trex requires 12 inch on center spacing for a diagonal lay.
4. Hidden fastener systems run $45.71 per 50 sq ft (Grip-Rite Ninja) up to $208.43 per 100 sq ft (TimberTech CONCEALoc), posted retailer prices.
5. A composite railing line kit starts at $249.99 for 36 in x 6 ft (Fiberon CitySide).
6. Board prices are set by local dealers, so get a per-linear-foot quote from yours.

## What is composite deck material?

Composite deck material is a manufactured board that blends wood fiber with plastic, sold in three builds: uncapped, capped, and PVC. Uncapped is the oldest style, an exposed blend with no shell. Capped wraps that same core in a plastic cap. PVC drops the wood fiber entirely. Trex, TimberTech, Fiberon, Deckorators, and MoistureShield sell composite lines; TimberTech and Fiberon also carry PVC lines (TimberTech Advanced PVC; Fiberon Paramount and Promenade).

## Capped composite vs. uncapped composite: what changes?

The cap is the difference. An uncapped board takes in moisture at every face, so it fades and swells faster near grade. A capped board wraps the core in a plastic shell on three or four sides, so staining and moisture pickup drop sharply on the faces that see weather. That is why most current lines from Trex, TimberTech, and Fiberon ship capped; uncapped now shows up mostly in budget tiers.

The tradeoff is material tier, not code. Both still frame and fasten as composite, not as solid lumber.

## Composite vs. PVC decking: what changes?

PVC uses a more complex extrusion with no wood fiber. It will not absorb water at a cut end the way composite can, so it is the pick for docks and pool decks. A backyard deck with normal drainage does fine on capped composite.

Board prices: Trex, TimberTech, Fiberon, Deckorators, and MoistureShield sell boards through local dealers and post no board price online. Get the per-board number from your dealer’s quote.

## What do hidden fasteners and railing actually cost?

Board pricing is the gap, but hardware posts a live figure. Deck and Rail Supply prices TimberTech and Grip-Rite fastener systems by the box; Fiberon prices railing kits direct.

| Item | Price | Retailer, captured |
| --- | --- | --- |
| TimberTech CONCEALoc fasteners | $208.43 / 100 sq ft | Deck and Rail Supply, 9/26/26 |
| TOPLoc composite deck screws | $64.17 to $66.50 / 100 sq ft | Deck and Rail Supply, 10/21/26 |
| Grip-Rite Ninja deck clips | $45.71 / 50 sq ft | Deck and Rail Supply, 9/26/26 |
| Fiberon CitySide line kit, 36 in x 6 ft | $249.99 | Fiberon direct, 9/26/26 |
| Fiberon CitySide stair kit, 42 in x 6 ft | $290.88 | Fiberon direct, 9/26/26 |

Each row is one retailer’s posted price, a data point, not an average.

## What joist spacing does composite decking need?

Both numbers come straight from manufacturer install pages. Trex’s guide states that composite decking joists should be spaced no more than 16 inches on center for a standard straight lay, and 12 inches on center when the decking runs diagonal. TimberTech’s guide confirms the same standard: composite decking laid straight uses the same 16 inch on center spacing as wood. That agreement between two competing manufacturers is why 16 inches on center is the number to frame to.

## How to take off a composite deck job

1. Confirm the build before you price boards Ask whether the spec calls for uncapped, capped, or PVC. That sets the material tier and, on some lines, the fastener spacing.
2. Frame joists to the manufacturer spacing Run 16 inches on center for a straight lay, per Trex and TimberTech’s own guides, and 12 inches on center for a diagonal lay, per Trex’s guide.
3. Price the hidden fastener system by square footage Clip systems are boxed by coverage, not by the board. Order against the framed deck area, then round to the next box.
4. Add fascia and railing as their own line items Railing kits and posts price separately, by length and post height. Keep them as their own lines, not folded into a per-square-foot rate.

## Price the deck job from a photo

SimplyWise Cost Estimator turns a job-site photo into an itemized estimate in about 6 seconds. Add decking, fasteners, and railing as separate lines, set your labor line, and send a branded quote the client signs to approve. It is $29.99/mo or $239.99/yr, about $20/mo on annual, with a 7-day free trial.

## Keep reading

- Deck Material Calculator (https://www.simplywise.com/blog/deck-material-calculator/): convert a footprint into board, joist, and clip counts.

## Sources

### Manufacturer install specs

- Trex, How to Space and Install Deck Joists (https://www.trex.com/academy/how-to-guides/all-guides/how-to-install-deck-joists/). 16 in OC standard, 12 in OC diagonal. Live 2026-09-26.
- TimberTech, Installing Composite Decking (https://www.timbertech.com/ideas/installing-composite-decking/). 16 in OC standard, straight lay. Live 2026-09-26.

### Hardware pricing (single-source, named)

- Deck and Rail Supply, CONCEALoc Hidden Fasteners (https://deckandrailsupply.com/collections/timbertech-azek-encapsulated-pvc-composite-decking/products/concealoc-hidden-fasteners-by-timbertech). $208.43 / 100 sq ft. 9/26/26.
- Deck and Rail Supply, TOPLoc Deck Screws (https://deckandrailsupply.com/collections/timbertech-azek-encapsulated-pvc-composite-decking/products/toploc-2-in-coated-composite-deck-screws). $64.17 to $66.50 / 100 sq ft. 10/21/26.
- Deck and Rail Supply, Grip-Rite Ninja Clips (https://deckandrailsupply.com/collections/wolf-perspective-decking-composite/products/grip-rite-ninja-hidden-deck-clip). $45.71 / 50 sq ft. 9/26/26.
- Fiberon, CitySide Line Kit (https://www.fiberondecking.com/products/cityside-traditional-railing-line-kit). $249.99, 36 in x 6 ft. 9/26/26.
- Fiberon, CitySide Stair Kit (https://www.fiberondecking.com/products/cityside-traditional-railing-stair-kit). $290.88, 42 in x 6 ft. 9/26/26.

### Product

- SimplyWise Cost Estimator, App Store (https://apps.apple.com/us/app/simplywise-cost-estimator/id6670619664), 4.8 rating, verified 2026-09-26.

## Frequently asked questions about composite deck material

### The material

**What is the difference between capped and uncapped composite decking?**

An uncapped board is exposed on every face, so it takes on moisture and fades faster. A capped board wraps a plastic shell around the core on three or four sides, depending on the line.

### Install specs

**What joist spacing should I use for composite decking?**

Trex’s installation guide caps a standard straight lay at 16 inches on center and requires 12 inches on center for a diagonal lay. TimberTech’s guide confirms the same 16 inch on center standard. Frame to 16 inches on center unless the lay is diagonal.

### Pricing the job

**How much do hidden fasteners cost for composite decking?**

Deck and Rail Supply prices Grip-Rite Ninja hidden clips at $45.71 per 50 sq ft and TimberTech’s CONCEALoc system at $208.43 per 100 sq ft, both captured live. Each figure is one retailer’s posted price, not an average.

**Why doesn’t this page list a per-linear-foot price for composite boards?**

Trex, TimberTech, Fiberon, Deckorators, and MoistureShield sell boards through local dealers, and their storefronts price sample kits, not boards. Prices change by dealer and region, so get the per-board number from your dealer’s quote.

**Can I start a composite deck estimate from a photo?**

Yes. Photograph the deck area, and SimplyWise Cost Estimator turns that photo into an itemized estimate in about 6 seconds. Every line carries its own quantity and price, so enter your measured footprint and adjust board, fastener, and railing lines before you send the quote.

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