A plumbing stack does several things. It carries wastewater from sinks, toilets, laundry, tubs, and showers through the house and out to the sewer. It prevents sewer gases from entering the home. It regulates pressure to allow smooth and consistent draining and is vented to allow fresh air into the system and help with draining. Without a stack or vent, your plumbing would not drain, and you would have sewer gas seeping into your home from the waste not draining properly.
Stacks consist of 3 major components:
- The soil stack- this is the bottom portion of the stack that connects the vertical stack to the horizontal building sewer. Anything with human waste goes into the soil stack.
- The drain stack- this is the middle section of the stack that serves as the connection for all household drains. Sinks, showers, tubs, and laundry all connect to the drain stack.
- The vent stack- this is the upper portion of the stack that goes out the roof to allow the proper air pressure into the system, as well as fresh air.
All of these components make up the plumbing system that allows for proper flow and keeps sewer gases out. All drain lines connect to the stack using special fittings. The drain lines all drain into the stack while gases escape the system through a vent.
Signs that your cast iron stack needs replacing:
- Slow draining/Backups- If your toilets, showers, tubs, or sinks are draining slowly, your cast iron pipes could be clogged or damaged. Cast iron pipes are rough on the inside, which can catch waste, such as toilet paper, creating clogs that can damage pipes.
- Leaks- Cast iron pipes crack over time and eventually leak, causing water on the floor or the ceilings of your home.
- Odor- Cast iron pipes with cracks may not show up with water but can seep a foul sewage odor, especially when draining.
- Barnacles- If you see brown, rusty barnacles on the side of the stack, this is a sign that the pipe is rusting from the inside out. Don’t scrape these off the stack, or a leak will occur.
Mold- If cast iron pipes are leaking behind a wall and go unnoticed, this causes a moist environment for mold to grow.