Use a penetrating finish rather than a film-forming coating
This rule is especially true for ipe and similar tropical hardwood decking, but in my opinion, it applies to all wood decks. Film-forming stains and clear finishes don’t do well at all on ipe, and they require too much maintenance to use on other species of wood. Tips for a Better Deck Finish
Boat owners may point out that film-forming coatings are a traditional and proven finish for teak and similar woods, but what they don’t mention is that varnish and similar finishes require regular seasonal maintenance. Homeowners are much less likely to scrape, sand, and refinish their decks every spring than they are their boat’s woodwork.
Use penetrating oils—but don’t use too much.
I have been told that ipe has the structural density of steel. Throw a piece in some water, and watch it sink. This density makes it a finishing anomaly. When you apply penetrating oil to softer woods, you can lay it on heavily and the wood will absorb it; ipe will spit most of the oil back out. The residue that is left behind will stay tacky for weeks, and then become a breeding ground for mildew.
Prefinish all six sides of the decking, and allow sufficient rack time for the finish to dry.
Prefinishing will extend the life cycle of the applied finish by blocking moisture absorption, especially on decks that are close to the ground, with minimal underside air circulation. The less moisture that wood absorbs, the less it will expand and contract, which will prolong the life of the finish. Remember, you get only one chance to finish the decking. Don’t forget to coat the end-grain.
Do not apply to finish using a sprayer, roller, or squeegee
It may not be comfortable to apply a penetrating oil with a brush, but that’s really the only way to do it properly. So get your kneepads on and do it the old-fashioned way, making sure you have plenty of clean rags to wipe up the excess. And be careful: Spontaneous Combustion is a real danger with a pile of oil-soaked rags, so be sure to soak your used rags in a bucket of water and dispose of them properly.
Don’t mislead the owner
Hardwood-deck owners basically have two choices for aging their wood: Do no maintenance and let it turn silvery gray like teak furniture, or maintain it periodically (every year or two) so it will age with remarkable grace. And if they maintain their teak furniture every year or two, it too will look a lot better—and last a lot longer. —S.B.