The short answer here is yes, but the truth is that it’s a bit more complicated than that. When you’re applying a second coat of sealer, you need to ensure that it will mix with the existing sealer. You don’t need to strip the existing sealer, but you do need to mix them. Fortunately, this is easier than it might seem. Simply apply the new sealer to the area, then use a broom to “agitate” the area and work everything together. The new sealer will then start to mix with the old sealer, and this will give you the best possible results. If you simply apply the new sealer on top of the old sealer, it will look great at first, but it will start to peel off and give you less than desirable results in no time at all.