Abstract: A jointing device for tents, covers etc., comprises two overlapping flaps interconnected by a series of yokes. The yokes are attached in spaced-apart relationship to one flap and pushed through corresponding through holes in the other flap. A rope-like member is passed through the yoke portions sticking out of the holes, thereby to hold said flaps together. According to the invention, an inflatable tube-shaped element having through holes is passed over the yokes and positioned between the rope-like member and the overlapping flap portions, or between said overlapping flap portions, and adapted, after inflation, to urge said rope-like member against the yokes to seal the joint between the flaps.