Yes, TDS Composite Sealer GL can technically be used on an older, sun-faded Trex fence, but it will not restore the original color. Teakdecking Systems (TDS) Composite Sealer is designed to form a clear, hydrophobic, deep-penetrating UV barrier. However, because it is a clear sealer with zero pigments, it will only freeze the weathered look in place and protect the fence from further UV breakdown, rather than bring back the fence's original vibrant shade.