Check whether its single or double skin - as said already said,single skin tents are not very warm or waterproof ? Also check what the base is made of as there seems to be new tents around now with the base sheet made of the same fabric as the rest of the tent ( therefore the so called groundsheet part is actually like the wall of the tent ). I bought an otherwise great tent but I had to return it because of this problem. (I tried waterproof sheet under base of tent (see Rapaires suggestion ) but it didn't work in this case, although it probably would with some tents.