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 in 2.2m lengths which are joined end-to-end to make the overall length a little longer than the length of the polytunnel. The gutter extends past the end of the polytunnel by about 8 inches 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.
See how to assemble your Polytunnel gutter