DekTek Tile's Sister Joist Installation Method is one of the main installation options when installing the concrete deck tiles on elevated decks.
Sister Joist Installation Brochure PDF
Framing For DekTek Tile's Concrete Decking:
Step 1.
Frame joists 16-inches on-center (OC). Add lateral blocking, same width as existing joists, a maximum of 4-feet OC.
Step 2.
A) Add sister joist to each existing joist. If joists are capable of supporting 10.5-pounds per sq. ft. dead load, then a 2x4 sister joist is sufficient. Otherwise, a full-length joist the same size as the existing will need to be added. The deck frame must be able to support a dead load of 10.5 pounds per square foot.
B) Place joist spacers no more than 24 inches apart in between the main joist and sister joist. Use two 16d galvanized nails or 3.5-inch screws to fasten the sister joist to the spacer and into the main joist. Add more 16d nails or 3.5-inch screws every 12 inches through the sister joist.
Add 1/4 to 1/2 inch joist spacer between the sister joist and the main joist to create a gap for better water drainage.
Two 16d nails or 3.5-inch screws need to be fastened into the sister joist at every spacer location, and a nail or screw every 12-inches.
Step 3.
Install the edge trim. Borders must be mechanically fastened at the outside edges to lock in the tiles. The most common border options are wood, composite, anodized aluminum, galvanized steel, or raising the facia board on the side of the deck 7/8" to lock in deck tiles. Border trim against house is optional.
Step 4.
DekTek Tile must be sealed with a high-quality solvent-based concrete sealer. (See sealing video below.) First, apply on all four sides of the tile and then the top of tile before installing. Do not seal bottom of tile. See sealing brochure for more information.
Setting The Deck Tiles
Step 5.
First layout the tile grid plan for overall tile positioning. When you start setting the tile, be sure to choose varied colors from the order to make sure the colors are mixed nicely. The tile must have a minimum of 1 inch bearing on each joist. Please note: Any tile cut to 10 inches or less needs extra support running under the bottom of the tile (i.e. an added 2x4). (See Deck Installation Tips For Planning & Installing Your DekTek Tile Concrete Tile Deck Video)
Tile is then set using a high quality exterior polyurethane adhesive directly to wood joists. Apply recommended adhesive (see adhesive brochure) to the joists as you lay your tile. Space tile joints 1/16 to 1/8 inch apart to allow for water drainage and the expansion / contraction of the tile. The joist spacing created in step 2, should be directly below the tile joints, as shown in the close-up, for the best water drainage. Cut tiles where needed. The tiles easily cut with a wet tile saw.
Tile setting skills are highly recommended.
Setting Equipment Needed:
- Caulk Gun
- 10" Wet Diamond Saw
- Chalk Line
- Tape Measure
For installation questions, please call 218-380-9330 or email us at info@dektektile.com. Thank you!
Sealing
DekTek Tiles should be sealed with a high-quality concrete sealer on top and all sides before installing. Be careful not to apply sealer to bottom of tile. When sealer is applied to bottom of tile it can break the bond of the adhesive.
Do not use a brush when sealing the surface of DekTek Tiles. It would be okay to use on the sides of the tiles if needed but using a brush on the top of the tile will cause brush marks.
Doubling Up The Deck Joists When Installing DekTek Tile’s Concrete Decking Using the Sister Joist Installation Method
Usually when installing the Sister Joist System, you have your main joist (often a 2x10 or 2x12) and then a 2x4 sister joist is added to the main joist to allow enough room for the deck tiles to sit on.
In certain situations however, a contractor or DIYer may need or prefer to double up the joists for added structural support. For example, on a deck remodel located in a state with less stringent framing requirements—such as many southern states that don't need to account for snow loads—if the existing joists are 2x8s spanning 10 feet or more, adding a 2x4 joist alone likely wouldn’t provide sufficient support. In cases like this, where additional strength is required, doubling up the joists would be the appropriate solution.
It is not required to double up the joists for all DekTek Tile deck installations, only when structurally needed or desired.