There are a number of trench drain manufacturers that sell 4 inch wide (100 mm) polymer concrete channels. In general, each manufacturer offers two grades of channel – “ residential and commercial.”  Hubbell, the maker of Polycast Trench Drain, is one of these companies. In this article, their residential product, 400 series, is compared to their commercial grade product, 600 series.

The photo to the left compares a 2 foot long section of a  Polycast 400 series (left) and 600 series channel (right). Both products are made from the same polymer concrete composition, which is a mixture of silica sand and epoxy resin. This material, while taking on some of the polymaic properties of the resin, displays the compressive strength of a concrete due to the high amount of silica sand. And though the material has the compressive strength which allows it to withstand heavy traffic while in service, it behaves as a ceramic and will crack upon impact or if dropped prior to installation.
Both channels have a similar 4” interior width and are available in 2 foot and 4 foot lengths. And from a functionality point of view, in low flow, low load applications both products perform equally. Most residential driveway applications would fall into this category.

Some of the differences between the 400 and 600 series are apparent in the above photo. Wall thickness of the 600 series is greater, which allows for heavier load bearing capabilities. Also, the channel end of the 600 series has a more integral male-female connection than does the 400 series product. Additionally, the grate used on the 400 series rests on top of the channel, while the 600 series channel actually has a recess within the channel for the grate to lie. However, a major difference between the two products is that the 400 channels are all non-sloped, while the 600 series channel are pre-sloped. The pre-sloped character of the 600 channel insures that water flows more quickly, thus allowing for higher overall flow rates. 600 Series channels can still be purchased without slope and are needed when designing complex drainage systems.

The 400 series product comes with a Class B galvanized steel slotted grate and is capable of withstanding loads from most automobiles. This is the only grating option. With the 600 series, you get a wider selection of grating options. You can get a Class B galvanized steel slotted grate, shown below. Or, you can upgrade to a cast iron or ductile iron grate for heavier loads. Stainless steel grates are even available for applications in a corrosive environment. In fact, there are 19 different grates options and four frame option for the 600 series channels.

The frames available with the 600 Series include a galvanized steel channel protector (shown above). This is a steel edge covering that keeps the channel from deteriorating while in use and helps increase the load capabilities of the system. The channel protector is also available in stainless steel. For heavy load capabilities (fork truck or airline) a cast iron or high density poly ethylene (HDPE) frame is used to cover the channel prior to inserting a ductile iron grate.

A final comparison between these two products is price. The 400 series product is manufactured for economy. It is a light duty product that is easily manufactured due to its uncomplicated dimensioning. It has only one grate option. Because of this, it sells for approximately 30% less expensive than the comparable 600 series product.
With the 600 series, you get flexibility and value. Though more expensive than the 400 series, the 600 series allow for higher load capabilities which can be further improved by changing your frame or grate. The 600 channels are more expensive due to the sturdier and pre-sloped design. And, of course, your choice of grating will directly influence your final $/foot price, especially if your application requires a stainless steel grate.
For a quotation on the Polycast 400 or 600 series products, email michael@trenchdrain.biz or call Trench Drain Systems at 610-638-1221.

Earlier in the year, I witnessed the installation of 40 LF of Polycast 600. Polycast 600 is a pre-sloped polymer concrete product manufactured by Hubbell. It is similar to many commercial grade products already out on the market. This particular product was sold with galvanized steel slotted grates and a steel channel protector. The channel protector (Polyguard) is a strip of galvanized steel that helps prevent premature edge deterioration of the polymer channel.

The job was located in the Pocono Mountains of Pennsylvania, earshot from the Pocono Raceway. The trench drain was to be installed in a new equipment storage facility. The floor of the facility was being pour at the same time as the drain in order to pitch the floor toward the drain.

Initially, the excavator roughed out a trench in which to install the drain. The site was already installed with gravel, but was not compacted.

(This will probably cause a problem in the future. The gravel base for trench drain and all concrete floor projects need to be compacted. This floor has an excellent chance of developing voids underneath the concrete in the future.)

The position of the drain was determined and a level line was set. Then, the trench was cleaned of debris to assure that the channels could be set without obstructions.

Next, the channels were set along side the trench in order that they would be installed. The highest number channel (deepest) was set at the discharge invert. The smallest channel number was set at the beginning of the drain flow path. For this particular installation, the channel protector and grates were both left in place. The grates were later protected with plastic sheeting prior to pouring concrete.

The discharge water was designed to exit the end of the drain through 4” PVC pipe. A hole was drilled through the foundation of the building for this pipe to exit. It was later tied into a drain pipe that took the water to a sewer.

Installation started with the deepest channel first, then proceeding upstream. The channels were connected to each other with an installation bracket and connected to ½” rebar (#4). This particular installation bracket is patented and used exclusively with the Polycast system. It makes installation easy. However, in this case, the installation would have been easier if the excavator hadn’t used so many large stones in the base. At times, large boulders have to be removed in order to hammer the rebar in the ground. No matter, the bracket was adjustable enough to line the channel up perfectly, even if the rebar stakes didn’t install perfectly.

From the photo to your left, you can get a better idea on how the Polycast installation chair works. Bolts from the installation chair fit into the “dimples” of adjoining channels to hold the channel tight. The bolts can adjust in our out to help align the channels left or right.  The chair can also be adjusted up or down on the rebar to keep the top of the drain (grate) on level.

Once the first few channels were put into place, the remainder of the installation went smoothly. The channels seemed to fall into the proper place when the installation chair was properly used. In the end, we had a 40 foot length of polymer concrete trench drain, suspended in air, and ready to be set in concrete.