When discussing catch basins with an excavating contractor, they may often think about the large precast concrete drainage structures for stormwater, which are regularly used in municipal, state or federal drainage systems. These basins commonly have an interior dimension of 2’ x 4’ or larger and are made of 8” thick reinforced concrete.
A landscape contractor’s perspective on catch basins however, may be different. Typically, the largest catch basin used in landscaping drainage systems is 2’ x 2’. Precast concrete basins are available in this size as well, but they are generally referred to as 2’ x 2’ yard basins.
There are several options available for landscape contractors and homeowners who need large catch basins. By large, I am referring to a basin with a maximum size of 2’ x 2’. A catch basin of this size (2’ x 2’) is at the boundary that separates commercial products from residential products. Basins larger than 2’ x 2’ are generally made with the intention of being exposed to heavy traffic loads. This article will be exploring some of the “large” catch basin products available for residential applications.
Pre-Cast Concrete Catch Basin
The first product is a traditional pre-cast concrete yard basin. These basins are made with metal forms in a concrete shape factory. The wall will generally contain some amount of mesh reinforcement and there are often indentations known as knockouts. These depressions make it convenient for a contractor to remove a section of the wall and install a drainage pipe.
Usually, the largest pipe that can fit into this basin is a 15” diameter concrete pipe. These basins can be made with pre-existing drainage pipe holes to your specification. Grating options are traditionally limited to heavy-duty slotted cast iron or steel bar grating. Though this type of basin is relatively inexpensive, they require a backhoe or small crane to set them into place. Your local pre-cast concrete company may have these in stock, but you will need some serious construction equipment to move and place it.
Cast-in-Place Concrete Catch Basin
If a pre-cast concrete catch basin is too heavy for you to handle by yourself, consider forming a large basin in place. Catch basin forming systems exist that allow you to build a concrete catch basin at your location. After digging a pit for the catch basin, set a metal frame and Styrofoam form inside the hole and suspend it with rebar above the base of the pit. The form will become the “reservoir” of the basin that collects all the water. The space around the form will become the concrete walls of the basin.
Prior to pouring concrete around the form, attach any drain pipe (entering or leaving) by simply butting it up to the form and securing it in some fashion.Once you have the form secured in place with all the desired plumbing, pour concrete around the form.
Depending on the size of the basin, you may choose to hire a ready mix concrete company to bring in “the mud”. However, if you excavated your hole with tight dimensional control you may feel comfortable hand mixing bagged concrete and saving yourself a little money.
I mention this because most ready mix concrete companies have a minimum delivery charge. If you are making a 2’ x 2’ x 2’ catch basin with a 6” thick wall, you will need a half yard of concrete (or 2000 lbs.). I’d probably get a concrete truck and pay the minimum charge. However, if I was going to make the walls of that same catch basin 3” thick, I might decide to hand mix the concrete.
Polymer Concrete Catch Basins
Another option for large yard basins is the polymer concrete catch basin. Polymer concrete is composed of natural mineral aggregates and a polymer binder. It has a very high strength in comparison to conventional concrete. This high strength allows very thin walled and light weight structures to be made with comparable properties as pre-cast concrete would have.
Product lines, such as Polycast, include 24” x 24” x 24” boxes that are use to build a catch basin. For additional depth, two foot deep extensions can be placed on top of the solid bottom basin. Smaller catch basins made with polymer concrete are available as well.
Attaching PVC piping to polymer concrete catch basins can be a little trickier especially since it is ideal to avoid using concrete when installing this catch basin. However, you may find it is necessary to use concrete to help seal the pipe in the basin wall or maybe when forming a small apron around the grating to help direct water into the basin.
And speaking of grating, polymer concrete catch basins may have some good residential grating options, but they tend to look industrial.
Plastic Catch Basins
The final basin type I am going to discuss is the plastic catch basin. There are a number of manufacturers in the marketplace that promote plastic catch basins. I’m most familiar with products by National Diversified Sales (NDS). These products range in size from 24” x 24” to 9” x 9”. The larger NDS basins are made from high density polyethylene (HDPE) while the smaller basins are made from PVC.
Extensions are available for adjusting the depth of the basin. Piping is connected to the basin with an adapter fitting and PVC glue can be used to secure the pipe and fitting, though it is not necessary.
Catch basin grating options become better as you decrease the drain’s size. For instance, the large 24” x 24” NDS catch basin has 5 grate options. On the other hand, NDS’ 12” x 12” basin has 15 options. Plastic grates in a variety of colors are common throughout the NDS basin product line. They also have cast iron and galvanized steel bar grating. Other manufacturers also have decorative grating options for the NDS basins. Iron Age Designs is one such company. Below are four decorative cast iron grates made for the NDS 12” x 12” catch basin. Some of these patterns are also available in sizes that fit other NDS basins.
As you can see from the examples I gave above, there are many options in large residential catch basins. I realize that the information given here may not answer all of your questions. To get more details on a product or advice on a catch basin application