The structure of this chapel is very similar to that of Chapel 3. Where the latter has ten sections in its dome, and ten columns in its base building, this one has twelve of each. The shortage of pieces at the moment of construction explains the limited height of the base building, which, by design, would have been twice or thrice as tall as the current one.

The twelve columns, with the spaces in between, form a 24-agon, which is made regular and rigid with the structure shown in the following picture:

As in chapel 3, two stacked antiprisms, now with 24 sides, are built on top of the columns. Also, there is a reinforcement structure, although it is simpler than that of Chapel 3. In the following picture, the balls A are the upper vertices of the upper antiprism, and the balls B form twelve tetrahedra. Each tetrahedron joins the adjacent ones with two triangles ABC which share the vertex C; this C balls are higher than both the B's and the A's.

The sections of the dome are segments of circular tetrahedric curves made of 34 tetrahedra. These segments join one another forming a regular dodecagon, as shown in the following picture. The spire of the dome is built on this dodecagon. Unlike Chapel 3, no helical segments are used here: