Resin bound surfacing works because a two-part resin coats every grain and cures into a continuous permeable matrix. Coating requires the resin to wet the grain surface. Water on that surface prevents it.
The result is not immediate failure. The surface looks correct when laid. Bond strength is simply lower than it should be everywhere, and the surface ravels — loose stone appearing first at edges and trafficked lines — usually within the first winter.
- Specify kiln-dried aggregate with the moisture result stated, not just the word "dried".
- Require sealed moisture-barrier bags, not woven bags.
- Do not lay over a damp substrate, and check substrate moisture as well as aggregate moisture.