Sika Post Fix 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 installing wooden, PVC and steel posts. Sika Post Fix is based upon Sika’s proven foam technology and designed for easy, convenient and quick support of many types of post.