Bostik SL-Gyp

Hybrid Gypsum-Based Self-Leveling Underlayment Bostik SL-Gyp™ A premium hybrid gypsum and cement-based self-leveling underlayment designed for challenging substrates, radiant floor systems, renovation work, and new construction. SL-Gyp™ combines smooth flow, rapid strength gain, high compressive strength, and broad substrate compatibility for demanding floor-leveling applications. Product Highlights Material Type Hybrid Gypsum Gypsum and cement-based formula Thickness 1/4"–2" Applied neat without extension Walkable Time 3–4 Hours Approximate return to foot traffic Compressive Strength Up to 5,000 PSI For demanding flooring applications Product Features Radiant Heat Compatible Suitable for use with hydronic and electric in-floor radiant heating systems. Flexible Installation Thickness Can be installed from 1/4 inch up to 2 inches thick without extension. Fast Return to Service Walkable in approximately 3 to 4 hours, with floor coverings installable in approximately 2 days. Exceptional Strength Provides compressive strength up to approximately 5,000 psi for demanding floor preparation projects. Ideal for Pumping Offers excellent flow and consistency for professional pumping applications. Low-Prep Applications Suitable for projects where shot-blasting or aggressive mechanical preparation cannot be performed. Excellent Healing Properties Maintains healing and pour-merging properties for up to approximately 20 minutes. Rapid Strength Gain Fast-curing performance helps support efficient construction and renovation schedules. Performance & Specifications Application Performance Application Thickness 1/4"–2" Neat Walkable Time Approximately 3–4 Hours Floor Covering Installation Approximately 2 Days Working / Healing Time Up to 20 Minutes Material Specifications Water Requirement 5 Quarts per 50 lb. Bag Compressive Strength Approximately 5,000 PSI Installation Method Pour or Pump Environmental Contribution May Contribute to LEED® Projects Recommended Applications Radiant Heating Systems Designed for use with in-floor hydronic and electric radiant heating systems. Distressed Gypsum Floors Suitable for repairing and leveling damaged or distressed gypsum-based substrates. Plywood & Lightweight Concrete Can be installed over structurally sound plywood and approved lightweight concrete substrates. Low-Prep Renovation Projects Ideal for applications where aggressive mechanical surface preparation is not practical. Mud Beds & Adhesive Residue Suitable for use over approved mud beds and properly prepared adhesive residue. Commercial & Residential Flooring Designed for demanding renovation and new-construction flooring applications. Product Image Product Resources Technical Data Sheet Bostik SL-Gyp™ Technical Data Sheet Safety Data Sheet Bostik SL-Gyp™ Safety Data Sheet Project Specifications SL-Gyp™ 3-Part Specifications Surface Preparation Bostik Surface Preparation Sell Sheet Application Tip: Measure the specified water amount carefully and maintain a consistent mixing and placement process to support uniform flow, leveling, and strength development. Important: Review the current Bostik Technical Data Sheet before installation. Confirm substrate suitability, required primer, surface preparation, mixing procedure, application thickness, curing conditions, moisture requirements, and floor-covering installation times.