Sikasil WS-295

Neutral cure, weather sealing silicone sealant

Sikasil-WS 295 sealant is a one part, neutral cure for use in most common weatherproofing applications on a wide variety of materials. Meets the requirements of ASTM C-920, Type S, Grade NS, Class 50, Use NT, M, G, A, O; TT-S-00230C, Type II, Class A; CAN/CGSB-19.13-M87, AAMA 802.3 Type II, AAMA 803.3, AAMA 805.2, AAMA 808.3.

Where to use

Sikasil WS-295 silicone sealant has been specifically designed:

  • As a weatherseal in both conventional glazing and structural glazing applications, including cap, toe and heel beads
  • As a weatherseal in glass to glass butt joint glazing
  • Sealing expansion and control joints in precast concrete panels and metal curtain walls
  • Perimeter sealing of doors, windows and other building components
  • Adhering stiffeners to building panels
  • Excellent for use in unitized curtain wall systems


  • Versatile medium modulus
  • Unaffected by most atmospheric conditions
  • Non-staining
  • Joint movement +/-50%
  • Excellent adhesion
  • One-component
  • Excellent gunnability in all temperatures



The number of joints and the joint width should be designed for a maximum of +/-25% movement of joint width at time of installation. The depth of the sealant should be 1/2 the width of the joint. The maximum depth is 1/2 inch (13mm) and the minimum is 1/4 inch (6mm). To control joint depth, use closed cell polyethylene, non-gassing polyolefin or open cell polyurethane backer rod. If joint depth does not allow for backer rod, use polyethylene bond breaker tape to prevent three-sided adhesion. Closed cell backer rod should be 25% larger than joint width; do not compress more than 40%. Open cell should be compressed 40%. Do not use open cell rod in horizontal on grade joints or with E.I.F.S. Ready to use, apply using professional caulking gun. Do not open product container until preparation work has been completed. Apply sealant using consistent, positive pressure to force sealant into the joint. Tool sealant to create a concave joint shape and maximum adhesion. Dry tooling is recommended. DO NOT use soapy water or other liquids when tooling.


See data sheet.