Installing a tropical hardwood deck with a species like Ipe or Cumaru is done the same way as your typical pressure treated Pine or even composite deck: face screwed or with hidden fasteners. Each deck fastener system method has pros and cons. Face screwing is fast and secure but it leaves exposed screw holes that many find unattractive. Hidden fasteners leave an unblemished beautiful face but most feel they take longer to install and leave the decking free to move about throughout the year. This can lead to an uneven deck surface. Of course, opinions vary wildly from one decking professional to another. Environment will play a major role in how your Ipe or Cumaru deck will perform. That being said, most of our customers prefer a hidden fastener when using tropical hardwoods for purely cosmetic reasons.
Hidden Fastening Systems
The added density and extreme hardness of tropical hardwoods is very tough on drills, drill bits, and screws. Ipe and Cumaru in particular have been known to burn out many a drill motor. It seems obvious therefore to spend less time drilling through the hard decking boards and focusing on drilling to fasten a clip into the softer deck sub-structure. Of course if you build your entire deck out of Ipe, from posts to joists to decking boards, you will still end up drilling into the harder wood. This is a small minority of the Ipe and Cumaru decks in the wild however. You cannot avoid drilling through these very hard woods not matter what method you choose since most clip systems still recommend drilling at an angle through the clip and bottom half of the deck board into the joist below. The clip systems will leave one edge of the board free to expand and contract in varying weather while still holding them firmly to the joists. The fine folks at Ipe Clip have a very helpful animation illustrating this movement.
It is this seasonal movement that many hidden fastener critics latch on to as the primary reason for face screwing. The fact that the boards can move means that they are free to warp, twist, and open uneven gaps on your surface. Moreover, the clips will reference off the joists and if they are not perfectly level then aligning the clip with the groove can be difficult. When you face screw the decking board, you can rely on the natural flexibility of the decking boards to secure them to the joists. As long as only one screw is placed across the width of the deck board, it is still free to expand and contract.
Ultimately with so many variables to consider, one is bound to see a wide variety of opinions on the topic of face screws versus hidden fasteners. After years of selling tropical hardwood decking we haven’t seen evidence that leans one way or the other that a method is superior. Really it comes down to personal taste and looking closely at the environmental conditions for YOUR deck. The key to a successful deck install that will remain stable and beautiful for years to come lies in the wood selection and planning for movement. A good quality decking board that has been carefully air dried will always be more stable in the long run and the type of fastening you do makes no difference. In fact improper installation (eg bad spacing between boards) is one of the most common reasons for problems with a deck installation. Choose your stock wisely and tell your lumber provider exactly where and how you will be using the lumber. A good dealer will help you determine the best species, thickness and width to ensure a beautiful deck now and in the future.