Unity Temple: The First Modern Building in America

Unity Temple stands at 875 Lake Street in Oak Park, on the corner of Kenilworth Avenue. From the sidewalk it reads as two cubic volumes joined by a low connecting hall: the larger auditorium block on the Lake Street side, the smaller parish house on the Kenilworth side. The whole exterior, walls, deep cantilevered eaves, ornamental bands, all of it, is poured concrete, left exposed as the finished surface. There is no stone facing the concrete. There is no brick veneer hiding it. The aggregate of the concrete mix is visible in the surface. It was finished by the building method, not after.

Frank Lloyd Wright designed Unity Temple for the Unitarian Universalist congregation of Oak Park between 1905 and 1908. He considered it his first modern building. Per the UNESCO World Heritage inscription that recognized it in July 2019 as part of the eight-building Frank Lloyd Wright Sites group, it is the first major reinforced concrete public building in America in which the concrete itself was the finished exterior surface.

That sentence is the building.

Why concrete

The congregation needed a new church because their wooden Gothic Revival church on this same site had been struck by lightning on June 4, 1905 and burned to the ground. The congregation was small, about four hundred members. The construction budget was tight: $45,000, less than half what a comparable masonry building would have cost. The lot was confined, the budget was constrained, and the congregation had no appetite for borrowed Gothic ornament after the burned predecessor.

Wright proposed concrete because it was cheap. That was the load-bearing argument with the building committee. Poured concrete required no skilled stonemasons. The forms could be built once and reused. The concrete itself, mixed on site, was a fraction of the cost of cut stone. A concrete building, Wright told the committee, could be built within their budget. A stone building could not.

But cheap was the argument. Modern was the consequence. By making the concrete the finished surface, by refusing to clad it in stone or brick, Wright committed to letting the material speak. The aggregate is visible. The form-board patterns are visible. The slight horizontal lifts where one pour stopped and the next began are visible. The wall is the structure and the structure is the finish. In 1908, that was an architectural argument no major public building in the United States had previously made.

The American architectural tradition before Unity Temple had treated concrete as a hidden material. It went into foundations, into structural cores, into industrial buildings the public was not meant to admire. It was never the surface of a church. Wright put it on the outside of a building people would pray inside. That decision is the line the architectural histories draw between Wright's Prairie houses, which preceded Unity Temple, and Wright's modern public architecture, which began with it.

The plan

The interior plan is the other half of the argument.

Most American Protestant churches of the period were variations on the Gothic processional. A long aisle, pews flanking the aisle, a deep chancel at the end, the congregation looking toward the pulpit and the choir. The architectural form expressed a hierarchy: clergy at one end, congregation at the other, the building's geometry pulling the eye forward.

Wright designed Unity Temple as a cube. The auditorium is a sixty-four-foot square room with the congregation seated on three sides of a central pulpit. The minister stands in the middle of the room rather than at one end. The fourth side is the entry from the connecting hall. There is no procession. There is no aisle. There is no chancel. The geometry is centered, not directional.

This is the architectural expression of Unitarian Universalist theology, which holds that the congregation is the source of authority and the minister is one among them. Wright did not invent the centered plan, which has antecedents in some Reformation traditions, but he expressed it with a clarity no previous American Protestant building had reached. The cube is the theology. The geometry is the doctrine.

The clerestory above the auditorium is a ring of leaded art-glass windows that admit daylight from above. The lower walls have minimal glazing. The room is lit from the sky rather than from the street. The effect from inside is luminous and inward, the room glowing without an obvious source. A visitor seated in the pews looks across the central space at other members of the congregation, not out at the world. The building is, in Wright's own description, designed for "the worship of God and the service of man."

What survived from the Prairie houses

If you have walked the Prairie houses of Oak Park before arriving at Unity Temple, you can read the building as the synthesis of the vocabulary Wright assembled across two decades of suburban commissions.

The cantilevered overhangs are here, projecting in concrete the way they projected in stucco and stone at the Heurtley House. The leaded art-glass clerestory uses the geometric vocabulary that first appeared in the Frank Thomas House and the Wright Home and Studio. The Roman brick that lined the garden walls of the Cheney House appears here in interior bands, anchoring the lower walls of the auditorium. The central hearth that organized the plan of every Prairie house Wright designed becomes, in Unity Temple, the central pulpit around which the congregation gathers. The fire becomes the speech.

What changes is the public scale and the material. The Prairie houses were sited on suburban lots for individual families. Unity Temple is a public building on a corner lot in a village center. The Prairie houses used wood frame, brick, stucco, and stone. Unity Temple uses concrete that is honest about being concrete. The grammar Wright had developed for the houses is here scaled up to civic use and committed to a new material.

That is what Wright meant by his first modern building. The Prairie houses were the rehearsal. Unity Temple is the public statement.

What to look for

Stand at the corner of Lake Street and Kenilworth and look up at the larger volume, the auditorium block. The first thing to register is that the entire surface is concrete. Not painted, not clad, not faced. The aggregate is visible in the wall. Run your eye along the deep cornice. The cantilever is six feet beyond the wall plane, which in 1908 was a substantial structural feat in poured concrete. The eaves are not decorative. They protect the wall from rain runoff in the way Wright's prairie-house eaves protected the wood and stucco walls below them.

Then look at the columns. There are four projecting square piers at each corner of the auditorium block. The piers are structural; they carry the weight of the cantilevered roof and the loads of the upper floors. The wall between the piers is non-structural infill. It can therefore be thinner than the piers, and it can be opened in places for windows without compromising the structure. This is the same structural principle that the Loop's steel-frame skyscrapers had begun applying twenty years earlier. Wright translated it into concrete and applied it to a religious building.

Now walk inside, if the congregation's open hours permit. The visitor enters through the low connecting hall between the two cubic blocks. The hall is deliberately compressed, low-ceilinged, dim. Then you turn into the auditorium and the room opens overhead into the sixty-four-foot cube, lit from the clerestory. The compression-and-release pattern is one Wright would use throughout his career, and Unity Temple is the public building where he established it. The architectural drama is in the transition from the low entry to the high room.

The interior is finished in unfinished oak and Roman brick, with deeply colored leaded glass in the clerestory and skylights. The pews are simple. The pulpit is centered. The room is one of the most photographed twentieth-century American interiors. Photographs do not prepare you for it. The light is the building.

Step back outside. Walk around the auditorium block to the south side. The exterior on the alley side is plainer than on the street sides, but the same material and the same vocabulary. Wright treated all four elevations as architecture, not just the public-facing ones. That, too, is what makes the building modern.

Unity Temple has been continuously in use by the same congregation since 1909. Restoration work between 2015 and 2017 returned the concrete surface, the leaded glass, and the interior finishes to near-original condition. Wright is buried in Wisconsin, but if you want to stand inside the building where his public modern architecture started, you stand inside this one. It is open to visitors. The congregation still uses it on Sundays. The cube is still doing its work.