UV stability is non-negotiable outdoors
On an interior floor, ambering only matters near a window. On a south-facing Okanagan patio it is visible after one summer, and it does not reverse. Any exterior quote listing a clear epoxy topcoat is a quote for a floor that will look wrong by next August.
Freeze-thaw and slab movement
Exterior slabs move far more than interior ones, thermal expansion in July, contraction in January, frost movement underneath. The system needs a more flexible resin, and the existing control joints must be honoured through the coating rather than filled flush. A rigid coating bridging a moving joint cracks along the slab lines in the first spring.
Slip resistance with bare feet
A pool deck is the highest-consequence slip environment there is: wet, bare feet, near a hard edge. Grip has to come from a broadcast rather than a topcoat additive, so it does not fade as the surface wears, and it has to grip without being uncomfortable underfoot.
Colour and heat
Dark colours on a south-facing deck get genuinely too hot to stand on in July. This is one of the few places we will actively argue against a colour choice, because a beautiful charcoal deck nobody can cross barefoot is a failed project however well it is installed.
Want this answered for your slab?
Free site visit with a moisture reading, then a written fixed price. Across the BC Interior.