Stiff joint foam is a rigid, high-density PE foam joint filler for concrete construction joints. The additional rigidity of stiff joint helps the joint remain straight in wet concrete and is commonly used for footpath and walkway jointing. Stiff joint is resilient, rot proof, heat resistant and non-absorbent making it ideal for use in external applications. Features and Benefits: Rigid and stiff for straight joints. Resilient, rot proof, heat resistant. Economical and Light Weight. Can be easily cut with a utility knife. Non-Absorbent