10 Ways to Finish the Ends of Composite Decking

Composite decking can last for decades and offers a wide range of colors and finishes that mimic natural wood. Unfortunately, the cut ends and edges don’t have the same characteristics as the board’s surface or real wood. If you’re wondering how to finish the ends of composite decking, we’re here to help!

Depending on who’s doing the work and their skill level, the ends can be rasped and painted, or covered with corner trim, edge boards, bullnose, or fascia of composite material. Plastic end caps, picture framing, butt joints, or using plants or planters to hide plank ends are other methods. Some finishes need to be planned and done before laying the deck boards, others can be added afterward.

In this guide, we’ll identify 10 ways to finish the ends of composite decking, explain their strengths and weaknesses, and whether you need to seal the ends. We’ll also identify which is the best way to finish the ends. Our aim is to provide you with the information to select the best finish for your deck project.

10 Ways to Finish the Ends of Composite Decking

Composite decking may look like real wood, but when you look at the ends, you know it isn’t. The ends may show that the decking is hollow, solid with a different color than the top, or the bottom of the board is sculpted or it has side grooves. It doesn’t look as good as the deck surface, so most professional installers use one method or another to hide the ends.

The purpose of edge or end finishing is to hide the ends of the boards in an attractive way that compliments and finishes the deck. The finish usually covers the ends and prevents some moisture and dirt from becoming trapped and damaging the decking.

It also helps keep wasps and other insects from nesting inside any open cavities within the boards too. To properly protect the cores and open cavities, make sure to cover the ends. Here are 10 ways the pros finish the ends of composite decking.

1. Rasp Edges

Cutting composite deck boards can leave a crisp, almost sharp edge, with strands of plastic material protruding from the cut. Using the smoother side of a rasp to lightly file a 45° bevel at the top edge is one solution. It can be used for both cut or manufactured ends. Only contact the edge on the down stroke to prevent ripping it on the upstroke.

The bevel breaks the sharp edge and removes any plastic barbs or feathers. It makes for a professional-looking cut, plus makes it easier to dress or finish the ends. The rasped edge also helps to hide slight height differences between boards. Instead of doing each plank at a time, the same bevel effect can be achieved using a small strip sander. Use 100 to 160 grit paper to create the bevel once all the planks are fastened into place and trimmed to length.

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2. Edge Board

Many composite deck boards are manufactured with fastener grooves along their edges, making them visible both at the ends and the exposed side. Some manufacturers have come out with edge boards; a color-matched composite plank with a fastening groove only along one side.

The boards commonly have an under-mount groove, leaving one edge smooth and natural looking. Edge boards can also be used to hide cut ends too. One potential drawback is that the edge board needs to be installed prior to installing other, parallel, deck boards.

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3. Composite Decking Bullnose Edge

Bullnose edge deck boards have one edge fully rounded while the other edge is grooved for hidden fasteners. The underside of the board near the bullnose is also grooved to receive under-mount clips. Bullnose decking is color-matched to complement the other deck boards, or a contrasting color can be used to provide an artistic flair. As with edge boards, bullnose planks must be installed before the other decking is installed.

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4. Corner Trim

Corner trim is made of composite decking material and has an L-shaped cross-sectional profile with a 45° bevel at both ends. The short or long leg of the L can be fastened on top of the decking. This allows the other leg to hang down to hide and protect the exposed plank ends.

The corner trim can be color matched to complement the decking or use a contrasting color to highlight it. Typically used on railed deck edges, it can be used on unrailed edges but creates a trip lip.

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5. Composite Fascia Boards – Skirting

Composite fascia boards can be used to finish and frame a deck. Just trim the decking to be flush with the rim boards. Install color matched or a contrasting color fascia board so the upper edge is flush with the top of the decking.

The fascia hides end cuts and open cores of the decking and offers some protection from insects and some moisture. It also creates a thin picture frame effect. Fasten the fascia with recommended adhesives or color-matched nails or screws.

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6. Picture Frame

A picture frame enhances a picture and hides the edges of the canvass. So, creating one for a deck improves the look and hides the ends of the deck boards. Since most composite decking has edge grooves and a sculpted bottom or open web core, manufacturers offer solid square, bevel, or bull-nosed edge fascia planks of equal thickness. Color-matched or contrasting fascia planks can be used for different purposes, but picture framing is a popular way to finish a deck.

The framing planks run perpendicular across the ends of the decking and can also run parallel to the sides, for a full picture frame effect. Corners are often mitered at 45° for 90° corners, or other angles depending on the deck design, or butt joined.

The framing pieces are usually fitted before the decking is laid. This allows them to be fitted around railing posts and so extra support framing can be added to ensure the decking is properly supported at its ends. Color-matched screws or nails, glue, or hidden fasteners can be used the secure the picture frame planks.

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7. Grain Paint

The inside of most composite decking is a different color than the outer finish, so the ends and any cuts show up more. Whether solid or hollow core and webbing, the ends expose the core material to moisture and insect damage. Most finishing methods hide the ends of the decking but don’t offer moisture or insect protection. One way to protect from moisture and mute any color differences is to use color-matched paint.

Most manufacturers offer color-matched paint that can be purchased. Alternatively, you can take a small cutoff piece to your local hardware or paint store. Have a pint of exterior or deck paint color-matched to your decking to apply with a small 1/2” or 3/4” brush.

The paint will blend the ends to the deck surface and help seal and protect the core material from moisture. Many pros will paint the end grain and any cuts with color matched-paint, even if finishing the ends with another method.

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8. Butt Joint Corner

A butt joint is where one board overlaps another to form a 90° corner. It is a simple straight joint that can be used on deck surfaces or to finish facia boards used for skirting. The pieces are face screwed or nailed with color-matched fasteners.

It is an alternative to mitering the ends at a 45° angle and trying to align and fasten them together. If using natural wood, the overlapping plank has exposed end grain. With composite decking, the exposed end reveals the inner core material which is a different color.

There are different methods of hiding the exposed ‘end grain’ of the overlapping composite plank. A common practice is to rasp the edges for a more professional look and then apply color-matched paint to help it blend in. Some manufacturers identify paint codes for color matching on their websites or take a small piece to your favorite paint supplier.

Another method is to make a veneer cap using a 1/8” thick piece of grained material cut from the surface of a scrap piece of matching decking. It is easier to apply the veneer before fastening the overlapping plank in place. Cut the veneer strip to size, and then use a CA Glue for PVC pipe and activator to cement it in place.

A good glue and activator are 2P10. It’s best to turn the deck board over first to prevent the activator from damaging the top finish surface.

Apply the glue to the back of the veneer piece and spray the activator onto the end grain of the plank. Align and press them together for 5 to 10 seconds. Use a rasp to trim the veneer to size and to bevel the edges. Apply color-match paint to blend the edges of the veneer.

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9. Edge The Perimeter With Another Material

There are numerous ways to edge the perimeter with another material depending on how high the deck is off the ground. For decks near the ground, consider planting shrubs around the exposed perimeter to hide the ends of deck boards. Building raised garden boxes can also hide the board ends.

For any deck elevation, use privacy screens to cover up board ends. Another method is to use a natural wood plank as fascia, skirting, or to form the picture frame to hide exposed ends.

The wood can be left natural or be stained or painted to complement or contrast with the composite decking. Some avid gardeners mount or suspend garden boxes or troughs to provide fresh produce, beautify the deck, and hide exposed decking ends.

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10. End Caps

Many composite decking manufacturers fabricate color-matched end caps for their hollow core boards. Typically made of plastic instead of composite material, they are more flexible, longer lasting, and more weather resistant than veneer caps.

Most end caps are brand designed to fit and match specific product colors and open-core configurations. Easy to install, just insert or align the endcap posts into the core openings and tap in with a rubber mallet. Some brands suggest using an adhesive, but most are good with the compression fit.

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Cons

Do You Need to Seal Cut Ends of Composite Decking?

Composite decking is durable and comes in a variety of colors and wood-look finishes to mimic real wood. Unfortunately, cuts and ends expose the inner core material to weathering and potential moisture damage. Covering the cuts and ends will help hide and protect them from some weathering and moisture damage.

Sealing composite plank ends with a deck sealer isn’t recommended for most brands. Sealer can stop moisture intrusion, but it also prevents the escape of moisture, which can cause greater damage. Painting the ends with color-matched latex paint helps blend the ends and provides moisture protection while allowing the ‘wood’ to still breathe.

What Is the Best Way to Hide a Composite Decking Ends?

The type of decking, design, elevation, and aesthetics of the deck often determine the best way to hide the ends of composite deck boards; as does the builder’s skill. Open-core ends are more noticeable than solid-core and may attract wasps and other insects.

Climate affects weathering, expansion, contraction, moisture damage to exposed cores, and if snow removal is necessary too. There are many factors to consider when choosing which method is best to hide composite deck board ends in your location.

The 10 options presented all help make the ends less noticeable or disappear, but only a few protect the ends from moisture and insects. The corner trim does both, but can be a trip hazard and makes sweeping and snow removal difficult due to the raised edge. Sweeping or pushing debris or snow off the deck under railings is difficult enough without adding the raised edge.

Deck boards that run perpendicular to the decking, such as raised fascia, bullnose, picture frame, or butt joints look good and hide the ends well. Unfortunately, they don’t address moisture or insect concerns due to the spacing for expansion and contraction. They also can be damaged when removing snow.

End caps prevent insect nesting and damage and offer some moisture protection, but discolor within a few years. They also only work on open-core ends. Beveling the edges of the board ends with a rasp or sandpaper makes for a more professional finish, and works well with other options, like paint.

Paint helps prevent moisture damage and blends the ends, but needs to be reapplied every 3 to 5 years. However, it only works on solid-core decking ends. Plants, planters, and other perimeter applications help hide the ends but don’t prevent moisture damage or close off open cores.

Whether finishing composite deck board ends with one method or a combination of methods, hiding or masking exposed ends should help protect them from moisture and insect damage. Pick one that fits your skill set, matches your aesthetic vision, and suits the climatic conditions it will be exposed to.

Hopefully, you are better prepared to pick the best way to finish the ends of your decking project.