Sika PostFix is a two-part, pre-proportioned polyurethane resin which when mixed produces an expanding foam. It has been specifically formulated and packaged to provide a lightweight, mix-in-the-bag, fast-setting and high-strength backfill for wooden, PVC and steel in ground supports. Sika® PostFix is based upon Sika's proven foam technology and designed for easy, convenient and quick support of many types of posts.