About 25 years ago we added a solar heated sunroom to the living room in our 1930's era house in Washington. Now I am refinishing the broad oak steps from the living room and painting walls in preparation for replacing some of the windows with Low E glass. The finish on the oak steps has never held up and I am looking for a product to use. I contacted the Minwax people, wondering if their stain and "Helmsman" overcoat would do the trick. They advised me not to use their product but instead to use Thompson's stain/Waterseal even though it was meant for exterior use. I e-mailed the Thompson's people and they said not to use their product due to the long drying time/strong odors. The problem with the room is that it gets very hot in the summer and cold in rainy months, though if it's sunny outside or even overcast it's quite comfortable. But the temperature fluctuation caused the former finish (stain/polyurethane) to discolor/dry out/not last long. Can anybody suggest a product to use? The steps are all sanded and ready to be re-finished.