BITUTAK® SA Base is an SBS-modified bitumen underlayment for use in approved non-system warranty applications. BITUTAK SA Base is a self-adhering waterproofing membrane composed of a tough reinforcement that is saturated and coated on both sides with a self-adhesive bituminous asphalt. The topside is covered with fine mineral matter for enhanced traction during application, and the underside is protected with a siliconized release film, easily removed before application.