SlabGasket Expansion Joint Replacement (+ XL Sizes) - Free Sample Pack SlabGasket is designed to easily replace rotten wood expansion joints SlabGasket "XL" is designed to easily replace larger rotten (2x4) wood expansion joints Test fit the various sizes of SlabGasket to insure a snug fit for your expansion joint replacements SlabGasket is available in 7 widths, two colors: Gray & Almond, and two heights. Installation can be as easy as scratching out the rotten wood and stepping in SlabGasket