Fireplaces are often centerpieces of living rooms, providing both fashion and function. Generally, a mantel sits above the fireplace, allowing for decorations or familial items to be placed on them, such as framed photographs. If your house has a fireplace but is without a mantel, you can install one with time and effort. However, you'll need to use a sealer so the mantel, whether it is wood or stone, does not become heat stained. Applying sealer to a mantel is simple, and the positive effects last for years.