Keep Rapid Set Postmix dry until it is ready to use. The 20kg bag has a showerproof polythene outer for normal site storage, but the packaging should remain intact and the dry contents protected from water.
Rapid Set Postmix should remain dry until you are ready to set the post.
Our Rapid Set Postmix is supplied in a 20kg bag with a showerproof polythene outer. That packaging is intended to cope with normal site storage conditions, but the bag should remain intact and the dry contents should still be protected from water before use.
This matters because the product is deliberately activated with clean water. It is a pre-blended post-setting material that is poured into the prepared post hole and then watered, rather than being mixed separately beforehand.
Once water is introduced, the setting reaction begins. The supplied guidance gives an initial set of approximately five to ten minutes, so accidental moisture reaching the dry material before the installation is ready is not part of the intended storage or preparation process.
Keep the bags protected until the post has been positioned and the installation is ready to proceed. Rapid Set Postmix can be used for suitable timber, metal and concrete posts, with larger project quantities estimated using our post mix calculator.