How to Install Composite Decking Over Concrete
A concrete stoop with steps can be a formidable obstacle when trying to build a deck. A massive concrete stoop will be difficult to remove. Most of the time you will need to break the concrete apart using a sledgehammer or jackhammer and haul the debris away. Many people choose to build over the stoop instead.
How to Install Composite Decking Over a Concrete Porch or Patio
Time and Cost
Learning how to install composite decking on a concrete slab is fairly simple. But the time it may take to put composite decking over a concrete front porch will depend on the size of the area. A smaller project can be knocked out in a weekend, but a larger project could take upwards of five days. Apart from the size of the area, the amount of time required will mostly depend on how much shimming is necessary for sleepers to form a level surface.
The average price range to have composite decking installed on concrete is around $30-$50 per square foot, depending on the composite chosen, specific site factors and design. If you do the labor yourself, you cut these numbers in half (or perhaps even more). Labor and non-decking materials typically make up 2/3rds of the total project cost.
* Extra drill bits may be necessary. Expect as many as one bit per 50 holes.
1) Leveling & Layout
A weathered patio surface (or a surface that isn’t perfectly even) will need to be fixed before laying your sleepers. Pour on a thin coat of self-leveling compound on uneven areas to solve this problem. You also have the option of giving the coat a slight slope, allowing you to direct water to run away from your house.
Once the space is prepared, you can start to plan the layout. Most importantly, your layout should include the location of sleepers and how each surface element will exist in relation to each other. Optionally, you can use a chalk line reel to create a visual layout of your plan to help guide your installation.
2) Placing & Installing Sleepers
Sleepers can be placed directly on the concrete, or they can be set apart with ½” PVC spacers. Sleepers can also be level or sloped, as long as their surface forms a single flat plane. Starting from the highest point in your patio, place your first sleeper in position, using plastic shims to raise low spots if necessary.
Use a hammer drill to pre-drill into the spacers, sleepers, and concrete. Secure with concrete screws, penetrating no less than 1” into the concrete. Place additional sleepers in the same manner, using a straight-edge to ensure each is consistent with the last. Finally, use flashing tape to cover the topside of each sleeper.
3) Installing Composite Decking on the Concrete Slab
Placing decking boards on sleepers is nearly identical to building them on a regular deck. It’s important to follow manufacturer’s instructions for installing decking. In general, starting from the outside of the deck and moving inward, screwing accent boards into place first. Starting with accent boards can help guide the addition of field boards.