If your polytunnel gutter is fixing to a timber side rail . . .
The aluminium gutter section fixes simply to the outside of the timber side rail and the rainwater runs off the polythene cover into the gutter.
The gutter section is supplied a little longer than the length of the polytunnel so the gutter extends past the end of the polytunnel so the rain water can run off into a water butt.
At the other end of the gutter section is a a ribbed insert for the gutter stop end. And where the gutter sections join together, an aluminium foil flashing strip ensures a perfect and long-lasting seal.