The complete guide
Starting a new 4ft (122cm) run with two posts
The two-post size option isn't designed to extend an existing line — it's a self-contained section with a post at each end, which makes it the right starting point for a new fence run, a stand-alone screen, or the first bay coming off a wall or existing structure. Set both posts to the same depth and check they're plumb before the concrete sets; the WPC (wood-plastic composite) boards will telegraph any lean in the posts along the whole panel.