Bluestone patios on Cape Cod

Bluestone is the stone most Cape Cod homeowners picture when they think of a patio, and for good reason. It is dense, it holds up to salt air and freeze-thaw cycles, and it weathers to a soft blue-gray that suits shingle and clapboard. It is also unforgiving of a poor base. Most of the bluestone failures we are called to fix (rocking stones, sunken corners, ponding water) started underground, not at the surface.

Our bluestone work is done by Blue Claw masons, not subcontractors. The crew that excavates and builds the base is the crew that cuts and sets the stone, and the same foreman runs the job from layout to final sweep.

Thermal vs natural cleft, joints and base.

Thermal bluestone has a flame-finished face: flat, consistent in thickness and slightly textured. It reads clean and formal, is comfortable underfoot, and is the usual choice for pool decks, dining terraces and contemporary architecture. Natural cleft keeps the stone's split face, with more color variation and an uneven surface. It suits older homes and informal gardens, but it is less even for furniture and bare feet.

Joints. On cut thermal bluestone we hold tight, consistent joints of about an eighth of an inch, so the patio reads as one surface. Natural cleft and irregular patterns get wider joints to suit the stone. Joint material (stone dust, polymeric sand or mortar) is chosen for the base and the use.

Base and drainage. Every patio starts with excavation to firm subgrade, a compacted gravel base sized to the soil and the load, and a pitch that moves water away from the house. Where the soil drains poorly or the patio collects roof runoff, we add a dry well or perimeter drain before any stone goes down. See drainage.

Dry-laid or mortar-set. Dry-laid bluestone on a compacted base is the most common choice and the easiest to repair. Mortar-set bluestone on a concrete slab suits steps, pool coping and areas over structures. We will recommend one at the site visit and explain why.