Aco Drain Upgrades

“Important Update to Article Dec 2014″  – since publishing this article on Aco drain upgrades, we have developed our own channel grating system, a cast iron decorative grille combined with a channel grate. The grille, known as Quatrefoil is available in one width (just over 4 inch, similar to the Aco system) but in various lengths  up to the standard length of 1 metre). Further details of the new Quatrefoil channel grate is here

Aco drainage gratings are very common and ideal for draining pathways, patios, gateways and gutters.

The modern galvanised slotted finish , so often used, is quite often out of sorts with listed properties and in conservation areas , it is for these reasons that clients quite often want to upgrade their Aco drain covers for something more “appropriate”.

We have a range of Lattice gratings in 4″, 6″ and 9″ (100mm, 150mm and 225mm) widths that may be suitable, all available in 36″ (910mm) lengths.

We also have a full range of square hole gratings available in widths ranging from 4″ (100mm) wide , 5″ (125mm), 6″ (150mm), 7″ (175mm) , 8″ ( 200mm), 9″ (225mm) and over. These are also available in 36″ lengths (910mm) .

The advantage of using the square hole gratings is that they can be shortened to almost any length. It is therefore possible to use a pair or more of the square hole gratings to match any length of Aco drain channels.

Firstly measure the Aco Drain cover width to check we have a grating that will be suitable.

Here are the gratings in cast iron we have that may be suitable:

Now remove the Aco drain cover, which may require unscrewing from the centre. It might be an idea to clear out the channel of debris while it is off. Check the body of the drainage channel is in good condition and suitable for supporting our cast iron grating.
Now, depending on the type of cover and the channel, you will need to make a decision on how you are going to secure our grating to the Aco channel, there are various options…

  • Re-use the existing securing screws you removed from the Aco cover. This might mean adding a washer to get the screw to clamp our cast iron grating or replacing the screws for longer or shorter screws.
  • Purchase machine screws, preferably countersunk of the correct diameter and length. Line up the cast iron gratings in position on top of the Aco drain channel and then drill using tapping size drill through the grating and into the lip on the top of the channel. Once all the holes are drilled, remove the cast iron grating and tap out the holes in the channel lip using the correct size tap. Now drill clearance holes in the cast iron grating for the screws to pass through (countersink if required) and screw down.
  • Ensure the lip of the channel is clean and dry and apply several blobs of clear silicon at various points along its length. Lower the cast iron grating into position and allow to set before use (24 hours). Ensure enough silicon is used to secure the grating but not too much to make removal impossible. When the grille needs to be removed for cleaning, just prise away from one end and cut away the old silicon with stanley knife blade before reapplying


These modifications are to improve the appearance of the Aco drain cover. There is no need to take out the channel beneath the cover, the Aco drain channel remains in place and the old cover is replaced with an elegant cast iron one as in the examples shown on the right.