Plumbing Vent Purpose:
These two questions about plumbing vent may seem pretty stupid but, in reality, a majority of people don’t know what a vent stack is and why it is necessary to have it installed with the drain plumbing system.
I intend to answer these two question s during this page and, how to fix a vent stack in case if the pipe is cracked or broken.
Plumbing Vent Stack:
A vent stack is also known as the roof vent or drain waste vent, in order words, it is the section of the drain plumbing system that goes from the bottom of the house all the way up to roof outside the house.
The plumbing vent stack is usually the main pipe of that particular branch of the plumbing system and, it usually is the place where you will find an access to the drains that are connected to it, however, it will not be always the case.
The Purpose Of A Vent:
It is extremely important to have plumbing vent stacks in strategic locations of the plumbing system for the following reasons:
Without vent stacks, it is likely the drain system won’t work efficiently, which means that, it most likely that drains throughout a plumbing system will have poor drainage or none at all.
Plumbing vent stacks allow effective exchange between air and water throughout the plumbing system, this allow the gravity law to work in its full capacity, which means that, with effective ventilation, the water will go down the drain with its full capacity while the does the same thing.
Drain waste vent is also vital to prevent sewer gas from going inside the house. When a drain system has proper ventilation, the sewer gas is expelled into the atmosphere instead of inside the house, therefore, preventing and protecting people’s health.
Sewer Gas Smell:
If you smell sewer gas inside the house, it is possible that a vent stack might be cracked or broken or maybe the gas is passing through other location such as: a rocking toilet with a broken wax seal or, maybe through a dried p-trap.
Before breaking dry walls to expose any vent, one should consider performing a smoky test and, for this particular job, you should contract a professional drain company to perform the test. It is a bit challenging and it will be required two people to have a complete test done. It will cost around $350.00 to perform a smoky test.
Cracked or Broken Drain Waste Vent:
Repairing a roof plumbing vent can be tricky and you may have to contract a professional to get the job done.
The level of difficulty to replace a vent stack will depend on the type of piping installed in the plumbing system; it will also depend on how the piping is installed from the beginning.
You will have to carefully investigate the situation in order to determine if this is a task that you will be able to start and finish it yourself.
Let’s say that your home has ABS piping throughout the house and the vent is well secured between the walls that leads to the roof, it this is the case, it is possible that you can do the job yourself but, if the hose is really old and the plumbing system is cast iron pipe, then, the situation will be completely different than the first.
Cast iron pipe is the heaviest plumbing material out there, the roof vent will much more complicated to be repaired, it will be necessary to make a lot of safety measures even before the work is done.
Repairing Cracked ABS Pipe Vent:
You will need the following parts and materials:
1 – One piece of ABS pipe of same measurement of the existing pipe.
2 –Two ABS Glue coupling of same measurement, 2 No Hubs or2 ferncos, whichever you prefer.
3 – One can of ABS Cement (if necessary) in case of glue coupling being used.
4 – Pipe saw, torque wrench or screw driver, strep tape, gloves, safety glasses, drywall knife.
Cut the drywall on the located spot to expose the pipe, check the pipe to make sure that is the right location and make sure the pipe is properly secured between the walls.
If toilets are connected to that stack, it is likely that the pipe will very secure, but, no matter what is the situation, use the strep tape to wrap the pipe to make sure that will be safe.
Cut the damage section of the pipe and remove it from the vent stack, use the old section to take measurement for the new pipe, cut the new pipe and with the 2 glue couplings or 2 no-hubs fittings connect the new section with the vent pipe.
If the 2 no-hubs are used, make sure to tighten them really well to prevent leaks. If glue couplings are used, don’t forget to use the ABS cement between them and the piping.
Repairing Cracked Cast Iron Vent:
If the home plumbing vent is cast iron pipe, the job will be a bit more challenging but can still be done by yourself, however, do it at your own discretion, otherwise contract a professional.
To repair this type of stack, you will all the above materials and tools but, you will also need a special tool to cut the cast iron pipe, it is called: Snap cutter or you can try an electric impact saw or hacksaw.
The steps to replace the pipe will almost identical but, before you even get there, you will have to make sure that the pipe is extremely secure; you will have to make special arrangement for that.
You will have to use steel strapping and anchor the pipe to the wall stud.
Once all the safety measures have been taken place, it is time to begin the repair of the pipe.
1 – Cut 2-4 inches beyond the crack on either end of the pipe and remove the cracked section.
2 – Cut a section of the new pipe the same length of the old one, can also be ABS.
3 – Connect the new section with the old section with two no-hubs or ferncos.
4 – Tighten the new section really well with the torque wrench.
5 – Remove the strapping and stud. You are done.