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Trex 4-in x 4-in Classic White Composite Deck Post Cap

Name: Trex 4-in x 4-in Classic White Composite Deck Post Cap
Brand: Trex
SKU: 1000712882
Rating: 4.4 (351 reviews)

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4.4

351

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Manufacturer Color/Finish: Classic White

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Shipping Details

The post sleeve cap rests on top of a Trex Post Sleeve (sold separately) to provide a finished, detailed look
This Trex railing component is made of a high-performance composite material that won't warp, rot, split or splinter
Cleans easily with soap and water
Backed by a 25-year Limited Residential Warranty
Decking and Railing Duos offer a simplified approach to deck design
The Trex Composite Deck Post Cap can be used universally with Trex Enhance, Select, and Transcend Railing
Trex Composite Deck Post Caps, Sleeves, and Skirts provide the finishing touches to Trex Deck Rail Kit (#1223182) and Trex Deck Stair Kit (#1223183)
Trex Enhance Composite Deck Rail Kits and Components are available in Charcoal Black, Classic White and Saddle

General
Package Quantity	1	Type	Post cap
Shape	Flat	Material	Composite
Manufacturer Color/Finish	Classic White	Finish	Prefinished
Color/Finish Family	White

Dimensions
Common Length (Inches)	4	Common Width (Inches)	4
Actual Thickness (Inches)	2.35	Fits Common Post Measurement	4-in x 4-in
Actual Width (Inches)	4.55	Actual Length (Inches)	4.55

Features
Pressure Treated	No	Lowe's Exclusive	No
Hardware Included	No

Warranty
Warranty	25-year limited

Certifications
CA Residents: Prop 65 Warning(s)	Prop 65 WARNING(S) -

Compatibility
For Use with Porches	Yes	For Use with Decking	Yes
For Use with Deck Stairs	Yes

Miscellaneous
UNSPSC	30103600

Check out the Best Selling Deck Post Caps on Lowes.com

Review

4.4 out of 5

351 Reviews

86% Recommend this product

Ratings may include incentivized customer reviews.

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+ 9

What Customers Are Saying

Customers overwhelmingly praise these post caps for their clean, stylish design and seamless integration with compatible deck systems, delivering a polished, professional finish. Most appreciate the white composite appearance that brightens outdoor spaces while maintaining a modern look. Many note easy installation without special tools and commend the low-maintenance durability and weather resistance. Some mention the caps are designed for 4.5-inch square posts rather than standard 4-inch posts, occasionally causing fit issues. A few report caps may shift in wind and suggest securing with silicone or caulk. Despite minor concerns, most customers consider them a worthwhile investment that enhances deck aesthetics.

Customer review summary generated by AI, including incentivized reviews.

351 Customer Reviews

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Fit on the sleeve perfectly. Good clean look to my new deck posts!

CooperSeptember 30, 2026
From 4-in x 4-in Charcoal Black Composite Deck Post Cap Verified Purchaser

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Response from TrexSupport

Thank you for your review! We're glad to hear the cap fit perfectly on the post sleeve and provided the clean, finished look you were hoping for.... Read More

TrexSupportOctober 5, 2026

Trex

Too big

Would Not Recommend

This is too big. Its more for a 5 x 5 inch post. Not sure why these are even sold.

DavidSeptember 22, 2026
From 4-in x 4-in Classic White Composite Deck Post Cap Verified Purchaser

Was this Review Helpful ?

Response from TrexSupport

We apologize for any confusion regarding the post cap dimensions. The actual dimensions of this post cap are 4.55" x 4.55", and it is designe... Read More

TrexSupportSeptember 24, 2026

Trex

Great product

A great addition to our porch remodel.

NitaSeptember 13, 2026
From 4-in x 4-in Charcoal Black Composite Deck Post Cap Verified Purchaser

Was this Review Helpful ?

Response from TrexSupport

Hello, and thank you for your review. We work hard to meet customer expectations, and we’re happy to hear we hit the mark for you! Thanks, Brooke - T... Read More

TrexSupportSeptember 14, 2026

Trex

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COMPARE PRODUCTS

		Name	Current Item Trex4-in x 4-in Classic White Composite Deck Post Cap
		Ratings	351
		Material	Composite
		Shape	Flat
		Finish	Prefinished
Trex4-in x 4-in Classic White Composite Deck Post Cap	Trex4-in x 4-in Classic White Composite Deck Post Cap	Trex4-in x 4-in Classic White Composite Deck Post Cap	Trex4-in x 4-in Charcoal Black Composite Deck Post Cap	Trex4-in x 4-in Charcoal Black Composite Deck Post Cap	Trex4-in x 4-in Vintage Lantern Composite Deck Post Cap	Trex4-in x 4-in Vintage Lantern Composite Deck Post Cap	Trex4-in x 4-in Vintage Lantern Composite Deck Post Cap	Trex4-in x 4-in Charcoal Black Composite Deck Post Cap
351	351	351	103	103	352	352	352	351
Composite	Composite	Composite	Composite	Composite	Composite	Composite	Composite	Composite
Flat	Flat	Flat	Flat	Flat	Flat	Flat	Flat	Flat
Prefinished	Prefinished	Prefinished	Prefinished	Prefinished	Prefinished	Prefinished	Prefinished	Prefinished