Abstract: In a slipform arrangement comprising a plurality of oblong, substantially rectangular mold plates arranged sequentially in a manner such that their end portions overlap each other there is provided an elongate post-like mold plate support means adjacent a short edge of an associated mold plate such as to support said plate in spaced relationship therewith, thereby to leave a gap for accommodating an end portion of a sequential mold plate, and tensioning means for creating in the region of said short edge a tensioning force directed substantially in the long direction of the post-like mold support. That part of the mold plate located nearest said short edge can be slightly angled towards the mold plate support means.