Footings dug and built over three campaigns by following the courses and from three changes to the widths of the buttresses. The south was more advanced as ground is higher in the southeast than northwest. On the outside the upper level stretches from the lowest three visible courses below the chamfer all the way from the tower to the north side of the projection for the east window. This campaign then drops to the footings on the north. On the interior of the southern wall the first plinth and torus in SW2 corner are placed diagonally, showing ribs were intended. I estimate that these three campaigns could have occupied the 1155-1157 seasons.
Footings laid to north side of entry into north chapel. Nothing was done along north transept wall, as there may have been some structure in the way that delayed work in this area for some years. Square-set plinths and tori were laid from south chapel to entry from north aisle. Apse walls to the 9th course with vertical breaks on outer sides of the apse entry shafts, which was three courses below start of windows. The joint is indicated by changes to buttresses. In both chapels lowest courses were built with thickened walls without any rib shafts, suggesting that in this campaign the master had not intended to vault the transepts, and when they reversed that decision in phase 12b the rib corbels had to be uncomfortably squeezed into the walls.
Apse of eight courses with windowsills and frames. The continuous external drip forms a skirt around the building.
Apse 8 or 9 courses to caps and square imposts, with start of vaults, window heads and entry arch that has a simple scooped profile; possibly a few courses in transepts and chapels while continuing the thick eastern wall in the chapels.
Completed the apse vault but did little on external walls so he could retain access to lay up the cells. In the south continued the south wall from tower to chapels. The master reduced the external diameter of the south chapel in fourth course below window drip; the fact that this does not occur on the north reinforces the evidence that they were being built in different phases. Began the S-s window in the lowest course, placed so it was not central to the wall. The joint is indicated where the buttress was reduced in the next course. In the north laid the footings and bases to the transept with different buttress widths, and built more on this side, yet it was still lower than the south. This campaign built altogether about 7 courses to a little below the north window. On the west laid the bases to the crossing piers and the opening into nave aisle with plinths angled true to the ribs.
In the chapels there was major changes from domical vaults to ribs. The thick wall was reduced in thickness to make room for shafts that were added over corbels to support additional arches over the entries into the chapels.
In the apse built the uppermost stones of wall and gable and coping to buttress with cornice with scooped profile and roof. Jambs for the S-s windowsill after lowest course in previous campaign with sill and shafts, and continuous drip so same profile as used before as skirt. Completed the whole of S-e window to the head with rings on the shafts. As it has the same window design as the apse this may have been the same master as in phase 9, being the return of the Scooped-profile master. The buttresses were reduced in the course above the string. The north chapel window was begun but not completed. Built the south chapel vaults with caps and arch entry, with the scooped profile. Unlike the south the north transept window N-n was set out centrally in the wall and one course lower than the south, a difference of 420mm, so it sat below the north chapel corbels.
This master employed the team that carved the capitals and arch to WN-w(a) aisle entry that continued the capital along wall. Used scooped profile to the voussoires.
In south transept set up S-s window with head twisted towards the east possibly so it would be seen centrally from the room. Completed head of S-e window with a modified scooped profile in the arch. Vault begun out of SW2 corner. Caps and arch entry into N chapel with extended impost. Began roof cornices to both chapels with this profile. Jambs to N-e window without rings on the shafts.
Consoles with figures were set into the walls of both transepts to support the ribs above the level of the chapel entry arches. They are not consistently aligned and look like an afterthought as they could have been carved with the capitals under the chapel entry arches.
Employing the carvers for the western clerestory capitals of the crossing. Originally all these capitals were at the same level, and then it was decided to raise the height of the crossing with a central lantern, thus ensuring a very tall nave. To achieve this some capitals were moved up 7 courses in the next campaign.
In the western crossing piers raised the opening into the nave 7 courses for a much taller interior, replacing the vault over the crossing with a lantern, and to do this relocated some capitals and imposts to this upper level, as can be seen in the angled edges of the imposts; that meant that there would be no vault over the crossing but a lantern. The arch into nave, and arches between crossing and transepts have a fillet-profile; vaulted the south transept with ribs with a groove on only one side (as in Soissons south transept); south chapel roof cornice and completed north N-n window head with centralised arch, and adjacent transept vault caps.
Shafts and capitals were inserted over apse piers for lantern
Completed transept vaults. Erected lantern walls over arches, and began twin windows and starts diagonal ribs with scooped-profile on ribs and around the frame of the windows. Completed transept vaults with south transept roof cornice. This could have been the same master returned two times before.
The decision for an 8-part vault may have been made here, or earlier. Completed the lantern vault and window head and Beauvaisis cornice.
Nave floor slopes from east to west. Erected the nave bases, dado and sills to the side walls. Also the W-w door and wall.
Nave aisle capitals and arcade arches. The tilted joint through windows meant that the W-w windows could not be started until here.
Wall above arches and aisle vaults to the triforium openings and clerestory caps in W1. Includes the start of the vault and clerestory window sills. Work continues to step down to the west.
Nave openings into roof area, clerestory, heads of windows, flyers and completes vault.