Expansion and Contraction Like most other plastics, ACRYLITE® extruded sheet will expand and contract from 3 to 8 times as much as glass or metals. The designer should be aware of its coefficient of expansion and make appropriate provisions. A 48" panel will expand and contract approximately .002" for each degree fahrenheit change in temperature. In outdoor use, where summer and winter temperatures differ as much as 100°F, a 48" sheet will expand and contract approximately 3/16". Sash rabbets must be of sufficient depth to allow for expansion as well as for contraction.

ACRYLITE® extruded sheet also absorbs water when exposed to high relative humidity, resulting in expansion of the sheet. At relative humidity of 100%, 80%, and 60%, the dimensional changes are 0.6%, 0.3% and 0.2%, respectively. Return to Acrylic skylights