UnderDeck® Outdoor Ceiling System

UnderDeck Logo

UnderDeck® Outdoor Deck Ceiling System

UnderDeck® is a new innovative maintenance free ceiling system that installs to the underside of second level decks.

It creates a clean, dry, bright area with positive drainage away from your home allowing you to use your new space rain or shine. It allows you to take full advantage of a space that typically gets started and never gets finished. UnderDeck will let you create an outdoor living space inexpensively while increasing your homes value.

Maximize Your Deck

UnderDeck® will allow you to screen-in your porch without all the expense and hassle of constructing an entire roof structure over your upper deck. UnderDeck is the simple answer to maximizing your deck and creating an outdoor living space as economically as possible. The UnderDeck solutions will give you both beauty and function in the same simple package.

Increase Your Home's Value

UnderDeck® will allow you to take full advantage of the lost and forgotten space under your deck. Increase the value without the increased taxes. Benefit from the transformation. The area that used to be the catch all for grass clippings has now been changed into a dry, bright, clean area. UnderDeck is the simple answer to maximizing your home's value while enjoying the your newly created outdoor living space. The UnderDeck solution will give you value, beauty and function in the same simple package.

Need More Space

UnderDeck is the fastest most economical solution to increasing your home's square footage. No need to dig footings and tear up the lawn to build a new addition when you already have the structure of a second level deck already built. Expand your living area under your deck. Create that outdoor kitchen you have always dreamed about. No need to keep the kids trapped in the kitchen on those evenings when you could be eating outside in your newly created outdoor living space. UnderDeck the simple solution.

UnderDeck Advantages:


  • Made of long-lasting, exterior grade vinyl
  • Maintenance-free and will not rust or corrode
  • 15-year limited warranty
  • Outlasts most decks
  • Will not react with pressure treated wood

Visually Appealing

  • Clean look brightens the area under your deck
  • Non-glare matte finish
  • Available in two colors -- classic white and tan on the Architectural Design Series and Pro Series, with the option of gray on the Standard Series. All of our colors utilize a low gloss on the gutters and a matte texture on the collector panels.
  • Attractive styling to upgrade your exterior

Cost Effective

  • Economical long lasting exterior grade vinyl
  • Simple installation
  • Increases your homes appraised value
  • Competitive and affordable price


  • Available in multiple lengths and widths
  • Attaches to the under side of second-level and multi-level decks
  • Installs in only a few hours
  • Creates positive drainage away from your home
  • Utilize the completed area for things such as: spas, storage, children’s play area or a screened-in porch

Easy to install

  • Lightweight seamless
  • Water tight virtually leak proof system
  • Allows for custom cuts, if required
  • Will not cut your hands during installation
  • Four components and four easy steps

      1. Snap – chalk line
      2. Tap – up joist rails
      3. Wrap – flex fit panels
      4. Cap – with joist gutters

Check List for Installation

UnderDeck is a product that can be installed in a weekend by the courageous do-it-yourselfer or in a couple of hours by a skilled craftsman.

  • Install flashing at building ledger and caulk top and sides of all flashing.
  • Install flashing over boundary gutter if at a building wall.
  • Move or cut out any obstructions (such as blocking, bracing, etc.).
  • Snap pitch line on joist (1 1/2" up on ledger end of joist, and 1/8" per foot drop on outside end of joist.)
  • Attach joist rails (Start 1" away from ledger and below chalk line, leave 2" space between rails.)
  • Insert collector panels.
  • Snap on joist and boundary gutters (Allow for 1/4" expansion). Make sure to use foam rubber dam (weather stripping) at house end of all gutters. Bend tab on drainage end of all gutters. (optional)
  • Install any additional gutters and downspouts if necessary.
  • Run a garden hose on the top of the deck (to test UnderDeck system).
  • Clean completed system and work area before departing.

Installation Guidelines

Begin by installing the necessary flashing at the ledger board and the boundaries of the deck, depending on the placement of existing house gutters. Caulk the top and sides of all flashing to prevent water from backing up and leaking at the ledger board.

Move or cut out obstructions such as blocking, bracing, etc., making sure the deck’s integrity is not compromised. Check local building codes for deck requirements regarding blocking or bracing.

Set the pitch line as follows: At the ledger board end of the joist, start the pitch line 1 1/2" (max.) from the bottom of the joist and drop the line at the rate of 1" per 10' (or 1/8" per foot) all the way to the outer end of the deck. Repeat this along the run of every side of every joist.

Once the pitch line has been drawn, attach the joist rails using two 1" – 11/2" galvanized roofing nails. The first joist rail should be attached 1" to 2" from the ledger board. Leave approximately 2" between rails to allow drainage from the collector panels to enter the gutter system.

Measure space between each joist and use the chart below to determine what to cut the collector panel width. Then cut collector panel length 1/4" shorter than joist length to accommodate expansion do to temperature changes.

Joist Space
Collector Panel Width
3 1/8" - 8"
Same as joist space
8 1/8" - 15 1/2"
Wider than joist space
15 1/8" - 18"
1" wider than joist space
18 1/8" -22 1/2"
11/2" wider than joist space

Install Collector panel by putting one long edge between the two flanges of rails along joist, then push up lightly in center of collector panel until other long edge slips into rails along joist.

Measure and cut boundary gutter and joist gutters 1/4" shorter than joist length.

Install boundary gutter by inserting backside of boundary gutter behind rail and push up until it snaps into place.

Install joist gutter by pushing up until joist gutter spreads out, and hook into rails by squeezing them firmly into the rail slots. Make sure to affix a foam rubber dam at the ledger end of all gutters. Leave a small space at the ends for expansion just as was done with the collector panels. (If joists rest on dropped beam, cut joist gutter 1 1/2" shorter than measurement from ledger board to beam.

Install custom gutters and downspouts if they were requested and included in the initial bid.

Using a mild cleaner and clean cloth, wipe over all gutters and panels to remove any marks or dirt from the installation process. Wiping down the panels and gutters as you go is recommended for a rapid install.

For more product and sales info, contact Tarheel Wood Treating, Hwy 54, Morrisville NC at 919-467-9176.

Return to All Products Page