Hi Jeremy
We’ve just put our first Ipe deck down and, with Amy’s post above, found two boards starting to cup within days following the recent heat-wave we’ve had in the UK. We solved the problem by soaking the board (it then laid nearly flat), strapping the underside of the board (yes, it wasn’t on a beam) and then screwing up into the cup ends to pull them down. Once this repair was effected, a little light sanding on one side and then oiling sealed the deck.
When we get our next project, I’m seriously considering Amy’s advice of sealing all four sides pre laying.
Best regards,
Mark