Notre-Dame du Haut

The structure is made mostly of concrete and is comparatively small, enclosed by thick walls, with the upturned roof supported on columns embedded within the walls, like a sail billowing in the windy currents on the hill top. In the interior, the spaces left between the walls and roof are filled with clerestory windows, as well as the asymmetric light from the wall openings, serve to further reinforce the sacred nature of the space and reinforce the relationship of the building with its surroundings. The lighting in the interior is soft and indirect, from the clerestory windows and reflecting off the whitewashed walls of the chapels with projecting towers.

The structure is built mostly of concrete and stone, which was a remnant of the original chapel built on the hilltop site destroyed during World War II. Some have described Ronchamp as the first Post-Modern building, and others as the first building of the movement Expressionist architecture after World War II. It was constructed in the early 1950s.

The main part of the structure consists of two concrete membranes separated by a space of 6'11", forming a shell which constitutes the roof of the building. This roof, both insulating and watertight, is supported by short struts, which form part of a vertical surface of concrete covered with "gunite" and which, in addition, brace the walls of old Vosges stone provided by the former chapel which was destroyed by the bombings. These walls which are without buttresses follow, in plan, the curvilinear forms calculated to provide stability to this rough masonry. A space of several centimeters between the shell of the roof and the vertical envelope of the walls furnishes a significant entry for daylight. The floor of the chapel follows the natural slope of the hill down towards the altar. Certain parts, in particular those upon which the interior and exterior altars rest, are of beautiful white stone from Bourgogne, as are the altars themselves. The towers are constructed of stone masonry and are capped by cement domes. The vertical elements of the chapel are surfaced with mortar sprayed on with a cement gun and then white-washed — both on the interior and exterior. The concrete shell of the roof is left rough, just as it comes from the formwork. Watertightness is effected by a built-up roofing with an exterior cladding of aluminium. The interior walls are white; the ceiling grey; the bench of African wood created by Savina; the communion bench is of cast iron made by the foundries of the Lure.

The South wall of Ronchamp is a creature of its own. Rather than designing a straight, 50 cm thick concrete piece, Le Corbusier spent months trying to perfect the outside wall. What he came up with is a wall that starts out as a point on the east end, and expands to up to 10 feet thick its west side. As it moves from east to west, it curves towards the south. To further expand his design's complexity, Le Corbusier decided to make the windows of the wall extraordinary. The openings slant towards their centers at varying degrees, thus letting in light at different angles. The different-sized windows are scattered in an irregular pattern across the wall. Le Corbusier reportedly insisted that the shapes and patterns were not arbitrary, but derived from a proportional system based on the Golden Section.[6] Furthermore, the glass that closes the windows off is set at alternating depths. This glass is sometimes clear, but is often decorated with small pieces of stained glass in typical Corbusier colors: red, green, and yellow. These stained pieces radiate like rubies, emeralds, and amethysts, and act as the jewels of the already complex wall. After this extensive design, Le Corbusier decided not to make the southern partition a bearing wall. Instead, the building's roof is supported by concrete columns that make it appear to float above the rest of the space.

In a final move of symbolism, Le Corbusier filled the inside of the wall with the rubble from the previous chapel that stood at the location. Thus the old church, and all of its history, would remain in the site.

Small pieces of stained glass are set deep within the walls, which are sometimes ten feet thick. The glass glows likes deep-set rubies and emeralds and amethysts and jewels of all colors.

Because it is a pilgrimage chapel, there are few people worshipping at most times. But on special feast days, large crowds of thousands will attend. To accommodate them, Le Corbusier also built an outside altar and pulpit, so the large crowds can sit or stand on a vast field on the top of the hill. A famous statue of the Virgin Mary, rescued from the ruins of the chapel destroyed during WWII, is encased in a special glass case in the wall, and it can be turned to face inward when the congregation is inside, or to face outward toward the visitors.

The roof was built in two parts, utilizing two softly upward curving reinforced concrete membranes, with a space between for insulation. The sinusoidal curved ceiling was formed with wooden framework and then whitewashed. The linear, textured impression left from the timber framework emphasizes the lines of increasing curvature of the roof.[7][8] Robin Evans believes that the ruled surface was integral to the roof design from the beginning, and may have been influenced by Antoine Pevsner's sculptures from welded metal rod, which Le Corbusier felt could be generalized as models for timber shuttering.[9]

Much like the church at Sainte Marie de La Tourette, the roof of Notre Dame du Haut appears to float above the walls. This is possible, because it is supported by concrete columns, not the walls themselves. The effect produced allows a strip of light to enter the building, thus lighting the space further, and making the church feel more open.

This billowing concrete roof was planned to slope toward the back, where a fountain of abstract forms is placed on the ground. When it rains, the water comes pouring off the roof and down onto the raised, slanted concrete structures, creating a dramatic natural fountain.