The really cool thing about DekTek’s concrete tile decks is that they are lightweight enough so the sub-structure doesn’t have to be “heavy duty” and expensive. Standard deck framing is usually sufficient with a few minor modifications: a 2x4 sister joist needs to be attached to each main joist for additional support. Or, if there aren't any heighth restrictions, then a 2x4 sleeper could be added to the top of the joists, running the opposite direction of the joists. This will make your deck 1-1/2" higher.
DekTek Tiles weigh approximately 11 lbs. per sq.ft. so the deck must be framed for a minimum of 11 lbs per sq. ft. dead load. If existing joists are not strong enough then you would need to add a bigger sister joist. Most decks framed with 2x10 joists will be sufficient. The beams that sit on the posts may need an additional 2x12 or 2x10 if the span is extra-long, or are supporting a large area. For questions regarding joist size and length of spans please refer to your local lumber yard for sizing. Visit Installation (link this to the installation tab) for more information on installing DekTek Tiles.