When the nascent Emmanuel church in prosperous post–Civil War Allegheny City created a building committee, it selected Malcolm Hay, a prominent Pittsburgh lawyer and politician, as its head. Hay possibly knew Richardson personally, but as an Episcopal layman, he had studied the designer's brilliant solution for the Episcopal liturgy in his Trinity Church in Boston. The committee selected Richardson for the commission in 1883. By the time Richardson committed himself to the work, he was also planning the Allegheny County Courthouse and Jail (AL1), in which Hay seems again to have played a role.
Richardson's first plans for Emmanuel were similar to his previous churches: Romanesque Revival in style but eclectic in detail. Richardson's first design adhered to the limitations of the plot (50 × 100 feet), but ignored the congregation's restricted budget. At $48,972, the projected cost was quadruple the budget, so the design was rejected. Eventually the building committee prevailed, and the church was built for only $12,300. In this budget fight—and not in some independent artistic source—lies the main reason for the simplicity of the plan and its reductionism from what until then had been Richardson's characteristically ornate style.
Emmanuel, massive and unadorned compared to the eclecticism of the other styles then present in Pittsburgh, is in no way visually poorer, thanks to the richness of its red brickwork and the striking comprehensiveness of its image. Five rows of voussoirs outline the three entrance arches and the tall windows that surmount and echo the entrance. The bricks outside the voussoirs are first laid in a basket-weave pattern, then in horizontal rows,
Neighbors have long referred to Emmanuel as the “bake-oven church” because of its unbroken transition to a semicircular apse. The interior is somewhat richer but still rustic, except for a white marble Tiffany-style glass reredos that was added in 1898 by Pittsburgh designers Leake and Greene. Richardson underestimated the thrust of the beams as well as the weight of the roof, which in just a few years gave the exterior aisle wall on Allegheny Avenue a picturesque but unthreatening batter. Frank Alden of Richardson's Boston office was called in to evaluate the wall, which he found to be architecturally sound. It was Alden, in 1888, who designed the adjoining parish house.
Though not an unsurpassed masterpiece, Emmanuel marks a significant turning point in Richardson's vocabulary. Given that a famous architect was here incited to better work by a steadfast patron, Emmanuel stands as a good design lesson even beyond its local significance.