Exterior concrete is the hardest thing we coat. Sun, freeze-thaw, standing water, pool chemistry and bare feet, all at once.
Standard Epoxy Does Not Belong Outside
Epoxy is aromatic, which means ultraviolet light breaks it down. Outdoors that is not a slow theoretical decline. A south-facing Okanagan deck will show ambering within one summer and chalking not long after. Any quote for an exterior slab that includes 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, and frost movement underneath. The coating has to flex with that. It also means existing control joints must be honoured through the coating rather than filled flush; a rigid coating bridging a moving joint cracks along exactly the line the slab does, usually in the first spring.
Slip Resistance With Bare Feet
A pool deck is the highest-consequence slip environment we work in: wet, with bare feet, near a hard edge. Grip has to come from a broadcast, flake or fine aggregate, rather than from an additive stirred into the topcoat, because broadcast texture is mechanical and does not fade as the surface wears. It also has to be tuned so it grips without being uncomfortable barefoot, which is a narrower window than people expect.
Heat Underfoot Is a Real Constraint
Dark colours on a south-facing Okanagan deck get genuinely too hot to stand on in July. This is one of the few areas where we will actively argue against a colour choice, because a beautiful charcoal deck that nobody can walk on barefoot is a failed project regardless of how well it is installed. Lighter and mid-tone blends stay usable.
Repairing What Is Already There
Exterior slabs are usually the most damaged concrete on a property, scaling from freeze-thaw, spalling at pool coping, organic and sunscreen staining, and failed expansion joints. All of that gets ground back, rebuilt and re-profiled before any coating goes on. On an older deck the repair can be a bigger share of the job than the coating itself.
What It Costs and When to Do It
Exterior systems run $9-$14 per square foot, above an equivalent interior floor because of the UV-stable chemistry and the additional repair. Timing matters: exterior work needs a stable weather window and slab temperatures in range, which in the Okanagan means roughly May through September, with the shoulder months dependent on the forecast.
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