Salt Meadow Archive

The copper is turning green. It has been doing so for decades — a slow, uneven oxidation that began at the seams where salt spray collects and is now spreading across the south-facing panels in a pattern that mirrors the prevailing wind. This is not deterioration. Copper does not corrode so much as convert: the metal trades its original surface for one that is harder, more stable, and more resistant to the environment that produced it.

Salt Meadow Archive stands on concrete pilings at the margin of a tidal salt marsh, where the ground is neither fully land nor fully water. The marsh floods on spring tides and storm surges, and the water table is never more than a meter below grade. Nothing here can be built on the ground; everything must be lifted above it, with enough clearance for the water to move through without resistance. The pilings are driven to bearing on a clay stratum seven meters down. The building sits above the marsh like a low bridge, casting a shadow that the cordgrass grows through without interruption.

The structure above the pilings is a timber frame — reclaimed Douglas fir sourced from a decommissioned industrial building of considerable age. The timber was inspected, graded, and recut to specification. Old-growth Douglas fir of this density and grain tightness is no longer available from standing forests; the only supply is what has already been used once and can be used again. The beams carry the marks of their previous service: bolt holes, iron staining, compression marks from loads they no longer bear. None of this was concealed. The wood has a history, and the building is the better for showing it.

Cladding and Skin

The exterior is divided between timber siding and copper sheet. The timber cladding is eastern white cedar — a species chosen for its natural resistance to moisture and its capacity to weather without protective coating. Left untreated, the cedar has silvered to a pale, driftwood gray that is nearly indistinguishable from the dried marsh grass in winter. The boards are shiplapped with generous overlap and installed over a ventilated rain screen cavity. Air moves continuously behind the cladding, carrying moisture away from the structural frame and preventing the conditions that would allow decay to begin.

The copper panels occupy the upper portion of the south and west facades — the faces most exposed to wind-driven salt spray. Copper was selected for these surfaces specifically because of how it responds to salt air: the patina it develops is a carbonate layer that becomes the material's own defense. The green is not paint; it is the copper's answer to its environment. The process takes years to begin and decades to complete. At this stage, roughly half the copper surface has turned; the remainder is a mottled brown that is itself an intermediate phase. In another twenty years, the entire surface will read as a single weathered green, and the building will look as though it grew out of the marsh rather than being placed upon it.

Moisture Management

Salt air is the dominant force acting on this building. It is not merely humid — it carries dissolved salt particulates that deposit on every surface and accelerate corrosion in any material susceptible to it. The design response is not to resist moisture but to manage its passage. Every material exposed to the exterior is either inherently resistant to salt corrosion (copper, cedar, concrete, stainless steel fasteners) or protected by materials that are.

The interior maintains a controlled environment that is notably more stable than the exterior conditions would suggest. The building envelope is designed as a series of layers: the outer rain screen, an air gap, a vapor-permeable membrane, rigid mineral wool insulation, a structural timber frame with additional cavity insulation, and an interior vapor retarder. Moisture migrates outward through this assembly, driven by vapor pressure differentials, and is evacuated at the rain screen cavity. The system is passive. It requires no mechanical dehumidification under normal conditions, though a small unit is available for periods of sustained high humidity.

The interior climate is maintained within narrow tolerances — temperature between 16 and 20 degrees Celsius, relative humidity between 45 and 55 percent — year-round. These conditions are sustained by a ground-source heat pump drawing from a closed loop beneath the marsh, supplemented by the thermal mass of the concrete pile caps and ground-floor slab. The stability of the interior environment is the building's primary technical achievement, and it is achieved with remarkably little energy input.

The Raised Foundation

The pilings are reinforced concrete, cast with a marine-grade mix designed for permanent immersion in brackish water. The concrete is dense, low-permeability, with a high slag content that resists chloride penetration. Each piling is monitored at intervals for chloride ingress and carbonation depth. After several decades of service, no piling has shown deterioration beyond the expected surface zone.

The elevation of the building above the marsh surface — approximately 2.4 meters from grade to the underside of the lowest beam — was established to accommodate a storm surge event with a statistical recurrence interval of two hundred years, plus an additional margin. The marsh has flooded beneath the structure multiple times. Water enters, moves through the cordgrass and pilings, and recedes. The building is untouched. This is not resilience as an afterthought; the entire building exists at this elevation because of the water, and the architecture follows from that single decision.

Aging

The most striking quality of Salt Meadow Archive is how it has come to resemble its surroundings. The silvered cedar, the greening copper, the concrete pilings stained with tideline marks and colonized by barnacles at their base — each surface has been written on by the environment over time. The building arrived as a collection of new materials. It is becoming a feature of the marsh.

The cedar siding has required no treatment beyond periodic inspection and replacement of individual boards where checking has compromised the weather seal — three boards in the most recent cycle, all on the southwest corner where exposure is greatest. The copper requires nothing. The concrete pilings require monitoring. The roof membrane was replaced once, at year twenty-five, as a preventive measure; the original membrane was still functional but approaching the end of its warranted service life.

The building is quiet. The marsh around it is not — it is populated with shorebirds, tidal movement, wind through the cordgrass — but the interior is held apart from that activity by the envelope and the elevation. What reaches the inside is muffled and low: the faint percussion of rain on the copper panels, the occasional deeper sound of a high tide against the pilings. The stability of the interior is the point. What the building holds, it holds in conditions that do not change.