Freeze-Thaw Performance: The Boston Decking Constraint
Pool decking in Greater Boston must survive 20–40 freeze-thaw cycles per year — days when temperatures rise above freezing during the day and drop below freezing overnight. Water that has infiltrated porous decking materials or penetrated joints expands when it freezes and contracts when it thaws, progressively breaking down any material that is not frost-resistant. This eliminates many decking options that are popular in warmer climates and requires careful attention to drainage design to prevent water from ponding on or under the deck surface.
Concrete that is not air-entrained or that has insufficient compressive strength will surface-scale in freeze-thaw conditions within a few seasons. Natural stone that is too porous or that has a layered structure — some slates and flagstones — will spall or delaminate. Pavers and tile that are not specifically rated for freeze-thaw exposure will crack. The practical implication is that material selection for a Boston pool deck must start with freeze-thaw rating, not appearance.