The step is mastaba-like having dimensions of by with a height of , and was slightly vaulted, in a fashion similar to Shepseskaf's mastaba. Overall, the structure was tall, and was fully encased in white Tura limestone. The Egyptologist Miroslav Verner believes this expansion was intended to convert the tomb into a full pyramid, possibly up to three steps high, but that concern over the tomb's stability prevented its construction. The tomb was enclosed on three sides – north, west, and south – by a thick, whitewashed mudbrick perimeter wall. The south wall starts with a bend at the edge of the solar boat pit, runs for along the entire east wall, and then along the north wall for terminating at the southern jamb of the courtyard entrance. The east side had a high wall cut into the rock, which formed a chamber with the pyramid where the queen was embalmed. The expansion project appears to coincide with an elevation in the status of Khentkaus I. She had a title that had not previously been found anywhere else in ancient Egypt, which has been interpreted as either "Mother of two kings of Upper and Lower Egypt" or "King of Upper and Lower Egypt, and Mother of the King of Upper and Lower Egypt". It appears that her monument was constructed by her sons, speculatively proposed to be Shepseskaf and Userkaf. -M23*L2:X1*X1-M23*L2:X1*X1-G14-R8-G39:X1-I10:D46:X1-Aa1*X1:V30-F35-D21:X1-D4-X1:N35-S29-W17:X1-D28*D28:D28*S29- A covered causeway, composed of three parallel walls, led from the valley to a chapel, situated on the south-east side of the tomb. Originally, the north causeway wall and the south perimeter wall left a passage wide. This was later split into two with the construction of a southern causeway wall which left a causeway passage around wide and a southern street passage around wide. The southern perimeter wall was dismantled, either naturally or from human interference, and later rebuilt. The original construction was made of large mudbrick brick of dark silt, the rebuild was made of small mudbricks of sandy silt, cased with limestone chips.