Abstract: An imperforate sheet of gasket material from which gaskets, for preventing leakage of fluid between opposed surfaces, can be made. The sheet, which may be produced by various methods, comprises a matrix of an elastically-compressible material and discrete volumes of substantially-rigid material so distributed therein that upon compressing the sheet between opposed surfaces, initially the matrix material solely resists compression and only thereafter do the discrete volumes also resist compression. The distribution is also such that the mean rate of compression over any area of the sheet is substantially the same as the mean rate of compression over another area of the sheet when the areas are similarly compressed. The discrete volumes form compression stops to resist undesirable over-compression of the sheet. Such a sheet has application in the automotive industry, gaskets made therefrom being particularly suitable for fluid-sealing in vehicle engines.