As is well documented in the Bible and elsewhere, in Bible times, the innermost area of a temple (often referred to as the Holy of Holies) was only permitted to be occupied by the head priest, and even then only once per year.
My question is: when during planning or construction was that location designated as a holy place?
Until designated as a holy place I would assume that craftsmen, construction workers, etc. would be allowed to occupy that space during construction, but I don't know for sure. It's also possible that the head priest would do all the work himself, but am not familiar with the culture and skills of that time period to know for sure whether he'd have been a jack-of-all-trades, or if the skilled construction would be performed by others.