By Elizabeth Ginns Britten Remove portions of the enclosure for better air circulation. Leave the enclosure completely sealed to help maintain either warm or cool temperatures on the bridge. Some owners prefer just a mildew-resistant, nontransparent fabric enclosure. A coated vinyl like Strataglass is a more UV- and scratch-resistant alternative to traditional clear panels. No matter what material your enclosure is, it's critical to keep it clean and well maintained. Some enclosures combine transparent panels with breathable fabrics like this one from Sunbrella.