Installing decking using Ipe wood, or Brazilian walnut, requires a different approach than other traditional decking materials. This kind of wood requires air flow underneath the decking, and it should never be installed directly onto the ground. The ground flow ventilation helps to ensure the mechanical and dimensional stability of the decking boards, as well as helps reduce the likelihood of cupping. How far off the ground the decking needs to be installed depends upon where you live. There can be local building codes which mandate deck and dock minimum raised-height requirements, such as is common in several southern states, including Florida and Louisiana.
Ipe wood decking also needs to be predrilled, regardless of whether you are using screws or nails to secure it to the frame and crossbeam supports. The reason you need to predrill it is because this wood is extremely hard. Additionally, whenever you are cutting the boards to the desired lengths, you need to make sure to use name brand carbide tipped saw blades to achieve smooth cuts on the ends. Any time you do cut Ipe boards, you should make sure to immediately seal them after cutting by using a clear aqueous wax end sealer, in order to reduce end checking.
When placing the Ipe boards, proper deck spacing has to be considered, as this kind of wood does have some shrinkage over time as it seasons and dries. The average rate of shrinkage is approximately 1/16 inch on ¾ by 3 ½ inch deck boards, and 1/8 inch on ¾ by 5 ½ inch and 1 by 5 ½ inch deck boards. It should be noted that in hot, dry regions, shrinkage could exceed the averages. Further, any time you are installing deck boards in temperatures below 40 degrees, the recommended spacing is with a 1/16 inch gap.