An attachment arrangement whereby a cover 18 can be attached to a support frame, the attachment arrangement comprising a mounting member 22 defining a re-entrant channel 26, the mounting member being secured to the support frame, a resilient clip member 28 located within the channel and securing the section of the cover within the channel, the attachment arrangement further comprising a protection member 30 located within the channel between the cover and the clip member, protecting the cover 18 from damage by the clip member, wherein the protection member includes projecting parts 30c that extend from the channel 26, overlying at least parts of the exterior of the mounting member. The protection member may be of a flexible material, such as rubber. Also disclosed is a polytunnel structure incorporating such an attachment arrangement, the structure may further comprise a rope or the like extending over the cover, the projecting parts spacing the rope from the cover
