First of all, Cuprinol is a better and more expensive product than Behr, commonly sold by Home Depot. Secondly, their is a moisture problem that first must be addressed to have any kind of finish adhere properly. When using wood siding, it is VERY IMPORTANT to apply a vapor barrier to the walls prior to installing the siding. Moisture from inside the home will move through the walls and soak the back of the siding, otherwise. Also, ventilation fans in each bathroom and kitchen should be installed and operating properly to keep moisture levels in check. When the siding was installed, its also impotant to back-prime wood siding to limit he amount of moisture pick-up through the back. This is true for paint OR stain. Many a failed paint job on newer sided homes can be blamed on this omission. By just treating the exterior of the home and applying another stain product, I doubt you will solve your problem. As far as smooth vs. rough side, the smooth side has a "mill glaze" which intereferes with the ability to soak up stain. Anytime an oil product is used on any kind of wood, a light sanding should always be performed to break the glaze. The rough side out is effective in assuring proper adhesion, but will not protect against back wetting. I wish I had better news for you, but I suspect you will find yourself painting and/or residing down the road. As for clear finishes, Cabot and Sikkens offer the absolute best performance, but you'll pay for it. Good luck.