9 time's out of 10 the reason your getting cupping is lack of ventilation underneath the deck / porch itself. The deck / porch should be roughly 24" off the ground w/ 3 open sides (this is ideal, but not the end of the world if you have slightly less). IPE is very stable, I'd be surprised if you have the proper ventilation and still getting cupping.

If you don't have the proper ventilation but still want to go with IPE your best best is to go with a 5/4x4 board and face screw (do not use hidden fasteners. There would still be no guaranties though.

Here are a few photos that hopefully show how the IPE is cupping. Thanks in advance for the feedback!

Front porch that faces north.

How high off the ground? Is the front and sides open?

The decking is not fastened correctly.

The cupping is pretty minimal.

The boards are actually lifting from the joists. The hidden fastener system was a poor choice. The solution is to screw the boards down to the joists.

The porches are approximately 24 - 30" off the ground. There are no areas that are open around it. Underneath both porches is large gravel with several drains. THE PHOTOS WILL EXPLAIN WHAT I CAN'T--The front porch is the area on the far right with two beams.

This is the back porch before the IPE decking. It also has the large gravel with drains.

From what your saying you have no ventilation when it needs yo be open on 3 sides in addition to being 24" off the ground. From my perspective this is more than likely why the decking is cupping. ANY type of decking material requires adequate ventilation and will cup or worse without it.

This post was edited by millworkman on Thu, Nov 29, 12 at 10:02

An equivalent lack of ventilation is why I gave up on my initial plan to use ipe on a deck I am reconstructing and am now planning on using aluminum decking.

kas

We've had to remove the Ipe on the back porch. We're currently discussing our options, hence the update. We are planning on closing the two drains (which is a whole separate challenge.) One of the proposals is fill would go in and, in essence, a reinforced garage floor would be on top of that. Cut stone like flagstone would be the surface.

Any suggestions would be very appreciated. This is a screened porch and it will be used a lot.

Thanks again.
Dalas, Texas

You could always go for an aluminum decking product. Would save you the cost of re-engineering and filling those areas. Cut stone would give you a better look in my opinion, plus minimal maintenance in the future. I hope the architect is eating the cost on ipe mishap!