score:15
The point at which The Temple became holy would be from its dedication forward.
The Temple was rebuilt a few times. Below is the dedication for the first temple.
1 Kings chapter 8 gives a description of the events surrounding the dedication which involved:
Upvote:-4
Judging entirely from Christian religion, as I'm not really entirely familiar with Judaism and we know that a lot of Christian practices come from Judaism, probably the site is designated as "holy" sometime after construction. I can't say for sure when, but as an example, in Christian churches which also have a "holy place" which is in the east end of the temple, it is designated as holy through a ritual which happens post-construction.
Upvote:9
Actually, in Jewish law, non-high priests are allowed in the Holy of Holies not only during the original construction, but when renovations or repairs are needed. Maimonides, in his code of Jewish law (Laws of the Holy Temple 7:23), thus states:
When builders [are required] to enter the Temple building to construct or repair it... it is a mitzvah for the [craftsmen] who enter to be priests who do not possess any disqualifying physical deformities. If no [capable craftsmen meeting those criteria] can be found, priests with disqualifying deformities should enter. If none are found, Levites should enter. If none are found, Israelites should enter... If no [capable craftsman] who are ritually pure can be found, impure [craftsmen] may enter.