Trex 4-in x 4-in Black Deck Drainage System Post flashing

Name: Trex 4-in x 4-in Black Deck Drainage System Post flashing
Brand: Trex
SKU: 5013962149
Price: 11.81 USD
Rating: 3 (4 reviews)

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Trex RainEscape is a unique under-deck drainage system that uses a network of troughs and downspout construction to keep rain, spills, and snow melt from dripping through elevated deck boards creating a dry space below the deck. The 4” x 4” Post Flash is a polyethylene boot that seals around the post railing when installing the Trex RainEscape Deck Drainage System.

Easily installed by any homeowner or deck builder
Once installed, the dry space below the second-story deck can be used for additional living space or storage
Can be installed on any 4” x 4” (10.16 cm x 10.16cm) post
Speeds up any installation and ensures a tight waterproof fit
Finish the space with lights, ceiling fans, entertainment components and more
Extends the life of your deck

General
Color/Finish Family	Black	Type	Post flashing
Manufacturer Color/Finish	Black	Material	Rubber
Series Name	RainEscape	Package Quantity	1

Dimensions
Length Measurement	4-in	Width Measurement	4-in

Features
Recommended Joist Spacing	12-in or 16-in	UV Resistant	Yes

Certifications
CA Residents: Prop 65 Warning(s)	No

Warranty
Warranty	20-year limited

Miscellaneous
UNSPSC	30103600

Check out the Best Selling Under Deck Ceiling Systems on Lowes.com

Review

3 out of 5

4 Reviews

4 Star

3 Star

2 Star

33% Recommend this product

Ratings may include incentivized customer reviews.

4 Customer Reviews

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Works great on a 4x4 post.

Would Recommend

Fast flashing

RezzMarch 10, 2026
Verified Purchaser

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Response from TrexSupport

Hello Rezz, we truly appreciate you taking the time to share your feedback with Trex and are delighted to hear that you love our products! Kindly, Ab...

TrexSupportMarch 10, 2026

Trex

6x6 not to be

Would Not Recommend

Was advertised as 6x6, delevered as 4x4. had to return. Store said that they only come in 4x4 identifying misleading advertising, but to cut them in quarters, tie together with flashing tape. Ho ho... Would probably work to flash a 4x4 post.

oldcuss101November 18, 2025

Was this Review Helpful ?

Response from TrexSupport

Thank you for your review of our Post Flash.
We currently manufacture the product only in a 4x4 size because 6x6 material varies significantly f...

TrexSupportNovember 21, 2025

Trex

Every flashing has torn while installing

Would Not Recommend

Every flashing has torn trying to slide it over the post. We even tried sanding posts down. Still tore. DO NOT BUY!

JWMay 17, 2023

Was this Review Helpful ?

Response from Dave

JW, We'd be happy to replace the product. Please send us a picture and your contact info to [email protected].

DaveMay 17, 2023

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Trex 4-in x 4-in Black Deck Drainage System Post flashing

Shop Trex

Pickup

Shipping

Delivery

Overview

Product Features

Specifications

General

Color/Finish Family

Type

Manufacturer Color/Finish

Material

Series Name

Package Quantity

Dimensions

Length Measurement

Width Measurement

Features

Recommended Joist Spacing

UV Resistant

Certifications

CA Residents: Prop 65 Warning(s)

Warranty

Warranty

Miscellaneous

UNSPSC

Community Q & A

1 Questions

1 Questions

Trex: Featured Videos

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Trex 4-in x 4-in Black Deck Drainage System Post flashing

Shop Trex

Pickup

Shipping

Delivery

Overview

Product Features

Specifications

Community Q & A

Trex: Featured Videos

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