TAMTECHseal TTSNF-1 1 gal Natural Finish Joint Hardener For Paver Sand & Paver Sealer. Joint Stabilizer / Hardener & Paver Sealer is a high performance product designed to harden and consolidate sand in joints and seal the surface of pavers, bricks and concrete. This water based polymer will stabilize the joints, prevent wash-out of the sand and help stop weeds from growing through the joints. The product also acts as a clear sealer to help protect against the weather, water, dirt, freeze thaw damage and staining. Fungicides were added to resist moss, mold, etc. Joint Hardener & Paver Sealer can be applied right after the installation of the pavers and has no odor, is safe to use and cleans up easily with water. The sealer is breathable, so moisture is not trapped in the pavers. It is an exterior and interior product that can be used on new or old pavers, bricks or concrete.