Concrete patio construction in Boston MA - a slab that holds up through winter

There isn't one flat price, because a Boston patio is priced on its size, what has to come out first and how much base the ground needs, and I only know that last part after seeing the yard. Access counts too, since wheeling concrete through a narrow side yard takes more labor than pouring from the truck at the curb. Size matters after the build as well, because the Boston Water and Sewer Commission bases its stormwater charge on each property's hard surface, so you can ask the commission how a new patio counts toward yours.

The base decides whether the slab lasts, because guidance for freezing climates says a slab poured on undisturbed topsoil will crack in its first winter. In that kind of climate, what goes under the surface matters more than the surface itself. Before you compare prices, compare what each contractor plans to put under the slab, and ask them to write it down.

Good-quality air-entrained concrete, which carries tiny air bubbles that give freezing water room to expand, is what the ready-mixed concrete industry's guidance recommends for slabs facing hard freeze and thaw. Ask whether each bid names air-entrained concrete for the patio, so you know you're comparing the same thing.

Pick a stretch when freezing weather is unlikely in the days right after the pour, because concrete that freezes while it's still soaked can be damaged. Industry guidance urges caution about pouring outdoor concrete in late fall, winter or early spring for that reason. Hot midday sun is the other risk, since it can leave a weak, dusty top, so a pour is best started early in the day.

Skip deicing chemicals that first winter, since the ready-mixed concrete guidance advises against them on a new patio and suggests only moderate amounts after that. Plan another way to handle ice that season, like shoveling early and spreading plain sand for grip. If you want a sealer later, late summer after a few dry days is a good time, because the concrete should be reasonably dry first.

Concrete cracks because the ground under it moves, and control joints give it a planned place to crack in a straight line instead of across the middle. Joints don't stop the ground from heaving, though, and a section that lifts at a joint edge becomes a trip hazard that has to be replaced. New concrete comes out a different color from old, so a patched section stays visible, which is why we'd rather get the base right the first time.