Ventilation is a serious problem. IPE will rot and warp if moisture trapped underneath. Requires adequate airflow to prevent condensation build up. While IPE is otherwise as close to indestructible as any wood can be, it is vulnerable to moisture and is specifically not rated for ground contact for this reason. If you use it on a rooftop deck, you should make sure there is airflow underneath. This may require vents on the house side and opening on the outside end of the deck with support rafters running outward (so air can flow under the boards.) I would also use as wide a board spacing as practical. Use of 5/4 board thickness would would slightly decrease the odds of warp/cupping and allow wider rafter spacing for better airflow. Most important issue is whether you can raise the deck sufficiently to allow adequate airflow underneath. If not, IPE not a good idea. (I do not know about Massaranduba)

Thanks, John. It's heartening to hear that a pro thinks highly of the project, since it took so much blood, sweat, and tears (and money) to do it. The deck was part of a pretty huge remodel/landscaping project, which I spottily documented on a side section of the blog I've been writing since our son was born - you can see more photos about the construction process and the landscaping that went along with it than you'd ever care to see at the link below. (Josh, BTW, is our son; I'm David. I'm not REALLY as obsessed with the little booger as it sounds, I've just gotten used to using my daddy-ly identity as my online handle.) Vents would surely be a good idea - probably something we should have thought of in the first place. Our contractor was and is very good, and had done a number of decks before, but nothing like this, and his main business is high-end home remodels, not decks. I shudder at the thought of retrofitting the vents in the HardiPlank (the stuff is a pain in the butt to work with, and messy), but I'll put some noggin time into figuring it out. I can't imagine the moisture/heat differential between the top and bottom of the planks, either in winter or in summer, is particularly good for the wood, and it might explain some of the early cupping and general movement. (Keeping the posts plumb and square is another problem, since the 4x4 ipe moves a lot more than the supplier advertised; he assured us that it doesn't move at all once it's in place, when in reality it's been twisting and shimmying like a belly dancer.) Just curious - why did you retire from answering outdoor finish questions? More hassle and controversy than it's worth? Incidentally, in case anyone out there is paying attention, I love the purpleheart, and no doubt the deck will outlive me - the Atlantic City boardwalk was supposedly made of the stuff back in the 70s, and is still just fine, in a much harsher climate than ours. But the expense was far above and beyond what we could have imagined in our worst fears, not in initial material cost, but in labor. It's just so difficult to work with and hard to fasten that the costs blew out of all budgeting and were hard to contain. Part of that was the contractor's inexperience in working with the stuff, and part of it was the complexity of the design, but be aware when you're doing a comparison with more traditional materials (redwood, cedar, composites, etc.) that the up-front cost is the least of your worries when dealing with these super-hard tropicals. Just my two cents' worth. I love it, and we wanted wood, not a composite, and didn't want to be replacing a redwood or cedar deck in ten or fifteen years, but we weren't prepared going in for what it would take in all-in cost. Here is a link that might be useful: Remodeling/landscaping album documenting the process

I don't care? Sorry man, I might be reading more into that statement than there is but actually I do care. My GC thought the cedar elements would look good (because it adds an element of visual difference) and being vertical, wouldn't see the use that the ipe floor would so it would last longer. I am here posting because I have my doubts, but didn't want to prejudice the question with that statement. I want a deck that will both look good and last, but it has to be all wood or composite that looks like wood. My preference in that case is to stick with all wood.

Its not really necessary at all,Steve never puts it on.It is something I recomend. For me and my Outfit is a very easy way to gard the fresh ipe from the water escaping from the green pt framing lumber in the first few important weeks of new construstion. Using the 490 hevay bodied adhesive also evens out the bad milling common to framing lumber in a small way. Using that material is one of the reasons I dont have yo yo calls on my projects on the subject of cupping while using 1x6 ipe. By no strech am I saying it is nessecary. In fact if you would love to avoid it, just avoid it. J.