וַיִּתֵּ֣ן דָּוִ֣יד לִשְׁלֹמֹ֣ה בְנ֡וֹ אֶת־תַּבְנִ֣ית הָאוּלָם֩ וְֽאֶת־בָּ֨תָּ֜יו וְגַנְזַכָּ֧יו וַעֲלִיֹּתָ֛יו וַחֲדָרָ֥יו הַפְּנִימִ֖ים וּבֵ֥ית הַכַּפֹּֽרֶת׃
Then David gave to Solomon his son the pattern of the porch [of the temple], and of the houses thereof, and of the treasuries thereof, and of the upper rooms thereof, and of the inner chambers thereof, and of the place of the ark-cover;
Rashi
and the height was one hundred and twenty But in I Kings (6:2), it is written: “and thirty cubits the height thereof.” How so? The height of the [first] floor from the floor of the house to the ceiling of the first upper story was thirty cubits, and from upper story to upper story up to the highest roof was ninety cubits, as is written: (I Chron. 28:11): “And David gave his son Solomon the pattern of the vestibule and its houses and its treasures and its upper stories.” From there it can be deduced that there were upper stories there.
Or HaChaim
If we apply just a little intelligence to the problem we will find that there is no problem at all. We must realise that Solomon did not build either his Temple or its furnishings according to arbitrary considerations. He was not motivated by the desire to erect a magnificent edifice which would confer glory on its builder. He followed instructions received from the prophet. The prophet told Solomon that the very measurements he told him about were an ancient tradition (Chronicles I 28,11) where David handed Solomon the exact blueprints of the Sanctuary he himself had not been allowed to build. Every little detail had been ordained by G'd, and Rashi explains that the prophet Samuel had received the detailed instructions about the shape and size of the Temple from G'd. We have a story in Midrash Shemuel chapter 15 according to which Rabbi Yirmiyah in the name of Rabbi Shimon related that G'd had given Moses the details of the eventual Temple while the latter was standing. Moses transmitted the information to Joshua while the latter was standing; Joshua in turn conveyed this information to the elders while they were standing; they in turn conveyed it to David while the latter was standing. David relayed the information to his son Solomon. At that point everything had already been committed to writing as mentioned in Chronicles II 35,4 by king Yoshiyahu. All this proves that all these details had been handed down from generation to generation. Thus far the words of the Midrash. You will have noted that whatever Solomon did was based on higher authority. This is what we call הלכה למשה מסיני.