foam for thermal and acoustic insulation. The common use of roller doors in Australian garages is discussed at Garage (residential) § In Australia. In terms of thermal insulation, the roller door has a typical insulation R-value of 4.9 to 5.2. A sheet steel garage door has a typical insulation R-value of 0.5 to 2.7. An application that needs more thermal insulation typically uses foam filled sectional garage door, which provides typical insulation R-values of 6.1 to 6.4. Although roller doors are very reliable, the rollers themselves tend to require some maintenance or replacement from time to time. Steel rollers require frequent lubricant and plastic ones tend to get replaced more often than others. There are "do-it-yourself" guides online for lubricating or replacing garage door rollers. Garage door materials Aluminum garage doors are usually found in commercial settings and not common for residential garage doors. Aluminum is typically only used for full view garage doors ( doors which are made up of glass sections divided by aluminum stiles). Aluminum doors are rust-proof, and low maintenance. Fiberglass and vinyl garage doors are composite units, combining a steel core behind a fiberglass or vinyl skin. They have also polyurethane insulated base sections or other types of foam insulation. These premium doors can match steel garage doors, and be a realistic imitation of wood (namely fiberglass units), but they may be more expensive than steel units. Fiberglass doors are commonly used near the ocean where salt water can ruin regular steel doors. Steel doors are the most common garage doors in today's market. They are available in a variety of sizes and styles, provide strength and security, are cost-competitive, and may have optional insulating value. Extra strength is available with two or three layers of galvanized steel with a low gauge number (0.6 - 0.7 mm steel panels). Wood garage doors offer aesthetic appeal, but they are high-maintenance and may be expensive. Low-priced wood garage doors may warp and break easily. Steel stamped construction A common material for a new garage door is steel sheet formed or stamped to look like a raised panel wooden door. Steel doors are available in uninsulated, insulated, and a 3 layer door also known as a sandwich style door. A design mimicking carriage house doors has become popular since the early 2000s, and many manufacturers clad the exterior of a steel door with composite, vinyl boards, or other