Once the channel gratings are all in place, carefully mortar/concrete the pathway ensuring the fall is towards the channel and the channel falls gently towards the drain hole. It may be worthwhile placing the cast iron Quatrefoil grilles in position to ensure the concrete doesn’t distort the plastic channel.
Allow to set and then clean along the plastic channel rebates were the cast iron grille will sit. Ensure the leaf trap is in position over the outlet drain hole and then screw the Quatrefoil grilles onto the channel. If there are several grilles to fit, lay all the grilles loosely in position before screwing them all in place. There are very small differences in the dimension on all castings so it may be necessary to swap Quatrefoils around to get the best fit and get an even gap between each grille.
The finish of the bare metal grilles will quickly rust to leave a natural rusty iron finish. If a black finish is preferred then choose a painted finish. These grilles will last many years regardless of the finish because the iron rust forms a barrier towards corrosion with or without the paint. It is likely the cast iron Quatrefoil grille will be strong enough to support pedestrian traffic even 100 years after installation.
More details on the Quatrefoil Channel Grating
Junction box for creating T L and X junctions