السعي on upper floors is valid عند جمهور العلماء, as the floors are within the boundaries of الصفا and المروةh — upper floors are مستحب for elderly and families due to less crowding.
Yes, performing السعي on the upper floors of the Mas'a (السعي corridor) is valid عند the vast majority of contemporary scholars. The المملكة العربية السعوديةn expansion of المسجد الحرام added multiple levels to the السعي corridor to accommodate the growing number of الحجاج. These upper floors are constructed between the same two hills of الصفا and المروةh, within the legitimate boundaries of the السعي path.
The permissibility is based on the principle that what matters is walking between الصفا and المروةh within their boundaries — the vertical elevation does not change the fundamental act. This is analogous to performing الطواف on the upper floors of the Mataf, which is universally accepted. Major scholars and the Saudi fatwa committees have affirmed the validity of upper-floor السعي.
Practically, the upper floors offer significant advantages: less crowding, smoother flow, better accessibility for wheelchair users, and a cooler environment. The green markers indicating where men should hasten their pace (raml) are present on all floors. The distance per lap is essentially the same regardless of floor level. For elderly الحجاج, those with mobility challenges, or families with young children, the upper floors are strongly مستحب for a safer and more comfortable السعي experience.
Source: Saudi اللجنة الدائمة for Scholarly Research and Ifta (al-Lajnah al-Da'imah)