These are the boards now that were butted tight together when installed.

I use Australian Timber Oil on the deck every year and am completely happy with the results (despite contrary opinions of the product) except I learned the hard way when I first started that Ipe absorbs the oil depending on how thick it is applied and shows every lap mark. I now use a sponge mop, apply a VERY thin coat and then wipe the whole length of the board smooth with the map so there are no lap marks. Better to go too dry than too wet. You can always do another coat but it`s a bear getting extra oil off.

Any wood decking needs to be gapped in both directions, width and length.

Phildog,

As with most natural wood materials used outdoors, Ipe will lose some of its moisture as it acclimates. As a high density hardwood, Ipe has some pretty spectacular mechanical properties including hardness, strength, fire resistance, termite resistance, rot resistance, etc. Unfortunately, Ipe hardwood will move somewhat (expand and contract) as it loses or gains moisture.

Here's some good infomation on the subject of proper wood acclimation: http://www.mataverdedecking.com/compare-woods/proper-wood-acclimation/

Here's some more info on care and maintenance of Ipe decking: http://www.mataverdedecking.com/care-and-maintenance/

I hope this information is helpful.

Chris

Here is a link that might be useful: Proper Wood Acclimation

Ipe shrinks when dry, and expands when wet.

Butting the boards tightly is BAD idea, unless the wood is totally green, not acclimated or dry whatsoever. Using green wood is not advisable.

I space 3/32" gaps for Ipe. They grow to nearly 1/4" in the summer, they close up to almost nothing in the winter. If the boards are butted tightly, they will cup severely when the wood gets wet and expands.

" If the boards are butted tightly, they will cup severely when the wood gets wet and expands. "

Worse than just cupping, they deck surface can buckle upwards and pull out the fastening (screws may even pull through).

Yes, brickeyee is 100% correct, cupping maybe the least of the worries. Cracking, checking, splitting all are very possible ramifications