Masonry and natural stone

Cut limestone, ledgestone, sandstone and full-bed natural stone over block or framed walls. Substrate gets a weather barrier, lath and a scratch coat before a single stone goes on. Stones get laid out dry first so the coursing, the color spread and the corner returns are decided before they are stuck down. Joints get struck consistently and cleaned while the mortar is still green — raked joints on rustic stone, tighter joints on cut stone.

Fireplaces get a poured footing below frost depth, a block core, a firebox and flue sized to actually draw, and a cap and chimney detailed so water sheds off instead of soaking in. Cast stone or cut stone caps go on hearths, shoulders and chimney tops for the same reason. Simpler fire features — a block fire pit with a steel insert, or a gas fire table pad — get built on the same base as the patio they sit in: 3/4" clean crushed base, 8" to 16" deep depending on the soil and the application, compacted in lifts.

Seat walls get a mortared core on 3/4" clean crushed base, 8" to 16" deep depending on the soil and the application, compacted in lifts, with drainage behind them, and a flat cap wide enough to sit on comfortably. Caps are laid with a slight fall so water runs off the face instead of standing on the joint and freezing. Columns and pilasters get built around a reinforced core, not stacked on a slab and hoped for.

Flagstone patios and paths get fitted on site: each piece cut to its neighbor rather than set in a grid with fat joints. Mortar-set flagstone goes over a concrete slab; dry-laid flagstone goes over the same 3/4" clean crushed base, compacted in lifts, with the joints filled in stone dust or gravel. Sandstone slab steps get set between boulders and shimmed on compacted rock so they sit dead still. Boulders get placed with the loader, buried a third of the way in, and turned so the weathered face points out.

Mortar that freezes before it cures is ruined mortar. Late in the season we tent the work and run heat so the wall stays above freezing while it sets, which is why some of our photos have plastic sheeting and a salamander heater in them. The same problem is why detailing matters here more than in a mild climate: flashing, drainage behind the veneer, and caps that shed water are what keep a wall from spalling apart after a few Bozeman winters.