How to Replace 1-Inch Thick Grates

1 in Thick Bar Grate

How do I replace 1-Inch Thick Grates

Over time expected loads have increased, and the 1″ thick grate has become a rarity. New construction projects often specify current standard sizes of 3/4″, 1.5″, or 2″ thick grates. However, there are applications where frames are incorporated to help raise the Load Class of the 3/4″ drainage grates. The thicker 1.5″ and 2″ grates are considered “Foundry” and most often used in tandem with frames or rails.

Shaping A Drainage Channel

There was a time when architects consistently specified 1″ thick cast iron grates for loading docks, warehouses and industrial areas. Typically, these heavy-duty grates were installed along with angle iron frames, by using the old wooden box form method. Considered a frame and grate type system, it allows the contractor a bit more freedom with slope and size of the final channel drain.

Today’s standardized version of a frame and grate system is often specified with a channel form made of foam, as is the case with many EconoDrain trench drain systems. Another option used on a number of applications is incorporating heavy-duty 1.5″ thick grates with rails to create a custom drain channel.  

trench drain install

Heavy-Duty Grate Material Options

FiberGlass Grates

Fiberglass Grates

Already a popular replacement choice, fiberglass grates have several things going for them. These grates are rust-proof, have load bearing capability, and have a high chemical resistance. Among the many reasons to choose fiberglass, it is also not susceptible to theft, due to their low scrap value. In the right circumstances a 1″ thick fiberglass grate will make a suitable replacement for aged cast iron.

Foundry Grates

Most foundries moved to supplying 1-1/2” thick grates, due to the traffic loads increasing over time. By increasing the thickness of these heavy-duty cast iron grates it in turn increased the amount of weight that can be distributed and supported. When specifying this type of drain cover, it is a best practice to consider what will be moving over the grates within your application. 

TDS-FP1200-FG1247R Stainless Steel

Steel Bar Grates

Steel bar grates might be the exception to the rule. You can find 1” thick bar grates in custom widths, lengths and styles. However, wider grates require more  bearing bars to keep the same level of strength as a narrow option. It is best to account for the traffic crossing over your drain when deciding which grate option to use for your application. The current standard is still the 1-1/2″ thick option which is available in both stainless and galvanized steel

New Modern Installation

Sometimes the best option is to replace the existing system with a new modern day option. Most often the cause to use this option is due to foundry grates not being available in the size your project requires. Sometimes, the reason is that the trough or channel is so damaged it has become unsafe to just use replacement grating. This may have an increased immediate cost, but will be cost effective over the long haul. There are multiple options available, depending on the application. 


Trench Drain Systems is one of the largest distributors in the United States who are committed to providing you with quick solutions to all your surface water runoff problems. Our professional staff can assess your project requirements and quickly offer you competitive pricing and information regarding the products you need. Contact us for a free quote or for further information on drainage solutions visit or

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