Our corbels may be cut, sanded, nailed, and basically installed the same way as any wood corbel. Advantages of Polyurethane:1. Interior and exterior use.2. Waterproof: they won't absorb moisture or mildew3. Lightweight and easy to install.4. Pre-primed and ready for paint (Note: Primer does not absorb stains. A pair of these tall corbel is great flaking a fireplace and another creative project you may have. See large tumb nail for examples.