Trench drains and slot drains often need to be completely sealed against leaks. In some cases the channel drain needs to be sealed to be water tight for simple code compliance. Other times, a trench drain is carrying chemicals that have an environmental impact and need to be sealed. In some cases you are just planning on expansion and contraction at a joint and need an appropriate sealant.
Channel Drain Joint Sealant
Designing for sealants
If your design utilizes long runs of trench drain or slot drain you will need a place for expansion and contraction of the concrete. If you can these are best placed at either end of a shorter trench drain and not through the channel. If the movement joint must go through the drain it is best to place this at a joint in the trench. This will allow the movement to happen at the bell and spigot end. In this case you would put a bond breaker on the back side of the trench drain bell and seal the joint with a flexible urethane sealant.
The other reason for sealant use in a trench drain is when there are chemicals that you are trying to contain. Some chemicals are not very harsh to trench drain materials and sealants while other are extremely destructive to the materials used to construct a trench drain. Before specifying the proper sealant consider this; The more chemical resistant a material, typically the less flexible it is. More flexible materials are typically attacked by strong chemicals making them a constant maintenance issue. Try to limit movement of the trench drain system to avoid cracking of the surrounding concrete. Carefully monitor the compaction of the soil to ensure the trench drain will not shift or settle causing cracks. Secondly, heavily reinforce the concrete encapsulation to ensure that any movement is so small that it will not for cracks in the trench drain body or sealant material.
Selecting a sealant
Trench drain and slot drain joint sealant are offered in two types: Flexible and Rigid. Flexible sealants are typically used to seal trench drain joints that are prone to movement or simply need to seal against water and weak chemical environments. We offer “SLUR” with is a urethane joint sealant. This joint sealant has excellent flexibility and adhesion but low chemical resistance. We recommend this sealant for general purpose applications such as sealing joints against water. We also use this sealant for light, weak, or infrequent chemical exposure such as in a kennel, automotive shop, fire station, etc. Note that silicone joint sealants can also work in this application. Be careful if buying a sealant at a local hardware store because some of the bond well but have no flexibility (such as liquid nails, power grip, etc.)
The next sealant we offer is “SLPF”. This is a rigid two part fiber infused paste. This is the same polyester material used to make channel drain bodies thickened and reinforced with fibers. It has good chemical resistance and high strength. It is not flexible though. Don’t use this in joints that are expected to move. Use this with our standard DTPF trench drains, DTSP slot drains, and DTUTPF utility trenches. The paste is about the consistency of peanut butter and once catalyzed takes about 10 minutes to cure to a solid. This makes the material a great match for water tight sealing of joints because it will permanently fuse two channels together. It will not hold them from movement if the building or concrete cracks though. This material is also utilized for sealing field fabrications of any kind.
The next sealant we offer is the “SLCF”. This is the same as the “SLPF” above except it is the highly chemical resistant version. Has basically the same properties but is made from vinyl ester resin imparting increased chemical resistance. This material bonds exceptionally well and is a rigid material. Typically used with our DTCF trench drains and DTUTCF utility trenches.
A final mention should be given for thermoplastic trench materials and metal channel drains. These materials are best welded together. Thermoplastic trenches are difficult to seal due to the nature that little sticks to them so welding of joints is the best method. Metal trenches can have a gasket or be welded. We prefer welded because it makes a strong water tight connection. In a critical application a weld can be tested with a die penetrant or electrically to ensure it is perfectly sealed.
If a trench drain or slot drain joint sealant is going to work properly it must be installed properly. This step must be carefully considered for any sealant to function as designed. The joint must be prepared by roughing up the surface and properly cleaning it. This step will allow for maximum adhesion. Much like trying to put paint on a pile of sand will not stick, the surface of the drain must be sound in order for any sealant to properly stick. Please read and follow the sealant use procedures found in our sealant guide.
The final step in any application requiring sealant is to test that it is functioning as designed. If this is a critical function of the design such as containing chemicals we recommend that you test the sealant. This is best done with a water test. Simply plug the outlet pipes and fill the trench with water. You do this before the concrete is placed so that you can see where the trench drain or slot drain might be leaking. This will ensure that the channel drain is completely water tight. The concrete placement around the drain will strengthen this water tight seal.
Drain Sealant Types by Channel Drain type
Precast Trench Drain Sealant
For DTPF trenches use the urethane sealant (SLUR) for water tightness, oils, and other diluted chemicals. For heavier chemical loading, field fabrications, or trench body repairs use SLPF rigid sealant.
Slot Pipe Drain Sealant
For DTSP slot drains use the urethane sealant (SLUR) for water tightness, oils, and other diluted chemicals. For heavier chemical loading, field fabrications, or slot drain body repairs use SLPF rigid sealant.
Stainless Steel Trench Drain Sealant
For DTSS stainless steel trenches we recommend ordering the sections welded (SLWD) in as long of sections as possible that can be maneuvered into position. Final field welding of any joints is preferred. A gasketed joint can be supplied but we do not recommend them. Generally an owner is specifying a stainless trench for bacterial or chemical concerns and gaskets do not work well for these applications.
Utility Trench Sealant
Utility trenches come in standard polyester (DTUTPF) and chemical resistant versions (DTUTCF). For DTUTPF trenches use the urethane sealant (SLUR) for water tightness, oils, and other diluted chemicals. For heavier chemical loading, field fabrications, or trench body repairs use SLPF rigid sealant. If you are using DTUTCF we recommend the SLCF rigid sealant to give the utility trench a sealed secondary containment ability and to match the chemical resistance of the trench body.
Chemical Resistant Trench Drain Sealant
For DTCF chemical resistant trench drains use the SLCF rigid joint sealant to give the trench drain a water tight seal. There is no need for a chemical resistant trench drain if it leaks.