Installing a Ground-Level Deck Over Concrete Patio

Courtesy Fiberon Decking

Do you need to replace a broken, ugly, stained concrete patio? Don't spend thousands of dollars (or break your own back) having it demolished.  Instead, install a ground-level deck right over it!  But first, you will need to install a sleeper system. Learn what it is, why you need it, and how to install it.

What is a sleeper system?  Here are the basics!

If you have a crumbling concrete patio that needs replacing, you should consider installing a deck using Fiberon® composite decking, available in a range of stunning colors that complement any space. It’s incredibly durable and, best of all, easy to maintain. Plus, you can install Fiberon decking easily over a patio or on a rooftop space on a sleeper system.

A sleeper system is a substructure comprising joists that sit between a solid surface (such as concrete) and the decking. Ground-level (and rooftop decks, for that matter) present unique challenges when it comes to water management and air circulation.  The sleeper system enables adequate drainage and ventilation which, in turn, protects the deck boards from damage due to moisture build-up. Sleepers also enable easier access to the area beneath the decking, either for clearing accumulated debris or maintaining the surface material.

Fiberon decking works with minimal clearance requirements

When used with a sleeper system, Fiberon composite decking is approved for installation with 1 ½” of clearance from the bottom of the deck board to the pad/concrete surface – meaning you can now install Fiberon deck boards almost anywhere.

Here are some more tips to ensure a successful sleeper system installation:

  • Sleepers must be at least 1-1/2 inches in both height and width.  For example, a minimum clearance can be obtained by placing a pressure-treated 2x4 on its side.
  • Install the sleepers directly on the concrete. The old patio's surface must be solid and reasonably flat. Gravel, sand, dirt, and concrete pavers are NOT suitable materials upon which to install the sleepers and decking because the sleepers are not sturdy enough to span gaps, as with a normal raised deck. 
  • You may need to use non-rotting shims or additional concrete underneath some of the sleepers to maintain level and add stability. 
  • Use sleepers that are code-approved, long lasting, and resistant to wet conditions and rot.  Pressure treated wood and recycled plastic lumber are both considered excellent choices for durable sleepers.
  • The sleepers should be fastened in place for stability. The screws/nails must penetrate the concrete by one inch or more.
  • Install the sleeper joists parallel to the direction of expected water run-off.
  • Apply standard spacing to the joists: no greater than 16 inches on center (o.c.) for residential applications; no greater than 12 inches o.c. for commercial applications.
  • Consider using spacers under the sleepers to further improve drainage (although it isn't mandatory). This may be valuable in situations where the base does not have a definite slope.
  • Allow a gap of at least 1/4" between the deck boards for additional ventilation and drainage. 
  • Use face fasteners (not hidden fasteners) to attach the deck boards to the sleepers.  This allows you to remove and/or replace deck boards (any decking material can be damaged), or if access under the deck becomes necessary.  Color-matched deck screws are available for most colors of composite decking.
  • And of course, please review all local building codes prior to beginning your project.

As with any project, knowledge of the product and preparation is key

Whether you’re preparing to take on your own DIY outdoor project, or collaborate with a professional builder, it’s important to understand the best practices for installing Fiberon Decking material. That’s why we encourage customers, as well as contracted builders, to educate themselves on our materials’ best installation practices. In this post we’ll highlight important recommendations and requirements that should not be overlooked to ensure the best, finished look of your new deck.

Tips for Proper Storage and Installation Tips for Composite Deck Boards

In order to protect your investment from the start, it’s important to store your composite boards in a level area. Keep products off the ground and covered on a flat, dry surface. Dark colors will absorb more heat than lighter colors and as such, will experience greater ranges in expansion/contraction.
The following preparation and installation procedures will result in less visible gapping:

  1. Keep boards out of direct sun during storage and cutting processes, and through to installation, if possible. Never cut and install boards in direct sun assuming them to be at ambient temperature.
  2. Longer boards have greater thermal expansion and contraction. Use short boards where possible for less visible gapping.
  3. There is less thermal expansion and contraction along the width of the board as opposed to the length. Using splitter/divider boards between each continuous run of boards will result in less gapping.
  4. Thermal expansion and contraction of the material can allow the boards to shift. Surface-fastening using heavy gauge (#9 or #10) quality composite deck screws will help keep the material in place.

Planning the Layout of Your Deck Boards

Careful planning of the finished deck layout will result in better looking finished projects. Fiberon composite deck boards are made to mimic the varied colors and grains of wood. Before you start installing your deck, it’s helpful to lay out the aesthetic pattern you want considering the wood tone variations and various grain patterns.

For example, you may want to line up boards in the same wood grain direction for a uniform look. An alternating direction style can add visual interest to your project. Also consider using two colors of deck boards with the lighter colored boards in the field of the deck and the darker colored boards as design accents around the perimeter of the deck.

Deck Fastener Options... face fastening or hidden fasteners?

Fiberon decking materials are designed to be installed with either face screws or hidden fasteners. Phantom hidden fasteners are specifically designed for Fiberon side-grooved boards and provide a smooth, fastener-free surface.

Face fastening can be accomplished with hidden or regular surface fastening screws. Cortex hidden face fasteners are installed on the surface and have deck plugs that cover the screw heads for a virtually fastener-free look. Stainless steel composite deck screws can be used for surface fastening; however, pre-drilling is recommended to prevent ends from splitting and will result in a better looking finished project. Follow installation instructions carefully for a flush finish with the deck surface. For decks using metal joisting, specialized surface fasteners are required that install at a 90-degree angle only.

Best Results When Adding Railings

Railings aren't typically required for ground-level decks, but are sometimes added for aesthetic reasons or to allow places to put shelving for plants, entertaining, etc.

There are two ways to install the posts for railings. The first, and most sturdy, is to set rot-proof posts into concrete around the perimeter of the deck. 

Or you can use surface fasteners to attach the posts directly to the deck. When using surface fasteners to secure railing to a composite deck, joist location may affect the ease, price and method of the installation of the railing system. Leaving the required 1.5” spacing for surface fastening at the end of the board and 1” from the side of the board, requires two joists for every end-to-end seam. Board seams with double joisting can affect post placement for your railing system.

You may also want to install additional sleepers beneath the decking to give the post supports more strength.  Planning is key, since once the decking is installed there is no easy way to go back!!

Thoroughly reading all installation instructions first will make for more successful projects. Failure to do so may result in a more difficult installation and may void the warranty.

Copyright 2019 G George Ventures Inc.