May one benefit and use the floor of the Sukkah?[1]
Ground:[2] The ground itself may be benefited from and hence even if the Sukkah fell apart during Sukkos, or was dismantled, one may use the ground space for other purposes.
Wooden floor: Some Poskim[3] rule that one may not benefit from the floor of the Sukkah if the floor was built for especially for the Sukkah, such as a wood floor. This applies even if one stipulated on using the floor from before the start of Sukkos.
Rugs and mats:[4] If one placed rugs or floor mats in his Sukkah he may not remove them from there and use them elsewhere during Sukkos. However, if one stipulated on them before Sukkos then it suffices.
[1] Piskeiy Teshuvos 638:1
[2] Igros Moshe 1:181
[3] Avnei Nezer 363; Igros Moshe ibid
[4] Igros Moshe ibid