Replacing cast iron vent stack: Cast iron vent stacks can be a pain to replace, and many people don’t know-how. Installing a new vent stack is an expensive job and is best left to a professional. If you are not sure what you are doing, it could be dangerous.
- Replacing cast iron vent stack
- How to attaching new dryer vent
- How do I replacing cast iron vent stack, and what type of vent should I use?
- How high can I vent a stack? What happens if I vent it too high?
- Can I vent more than one fixture on a stack?
- What is offset distance? How far from my neighbor’s property can I vent my stack?
Replacing cast iron vent stack
The first step in replacing a vent stack is to remove the old one. Often, this means cutting through the top of the chimney and removing it from the inside. This can be very dangerous and is best left to a professional. If you don’t have a professional to handle this for you, make sure you are very careful.
To replace a stack from inside your chimney, you need to cut out a section of the top of your chimney. Make sure you cut between two bricks so that your new stack will sit securely on top of your chimney. Once this is done, remove the old vent stack and install your new one.
If there is no way for you to cut out a section of your chimney from within, it will be necessary to remove the entire top of the chimney from outside. If this is necessary, make sure that someone holds onto the top as it comes down so that no one gets hurt by falling bricks or concrete chunks. Cast iron vent stacks can be a pain to replace, and many people don’t know-how.
Installing a new vent stack is an expensive job and is best left to a professional. If you are not sure what you are doing, it could be dangerous. Once you have the top of the chimney removed, you can install your new vent stack. If you are replacing a pipe, then it will be necessary to seal off the end. If you are replacing a brick chimney, then it is best to leave one end open. You do not want to seal off both ends, or else your house will not be able to breathe.
Whether you are installing a new vent stack or replacing an old one, it is best to have a professional handle the job for you. If not, make sure that it is done safely and by someone who knows what they are doing. This will ensure that neither your home nor anyone inside of it gets hurt during this job.
You can either have the old cast iron pipe removed and replaced with a plastic or attach a new dryer vent to it.
The problem is finding a size that matches the opening at the top of the chimney for your dryer vent. You’ll also need to decide whether or not you want to have insulation, which placed in between the pipe and the chimney.
How to attaching new dryer vent
The process for attaching a new dryer vent is pretty simple:
- Cut the opening in the pipe to install your dryer vent.
- Attach a transition piece (connecting elbow) to the top of your chimney.
- Securely fasten this elbow to the chimney with galvanized steel straps or screws at the top of the elbow.
- Attach a vent hood to the bottom of your dryer vent, and seal around all seams with high-temperature silicone or stainless steel tape.
- Securely fasten this transition piece to your dryer vent with screws, and then attach the vinyl vent on the other end to the wall where you’d like to vent your dryer.
- Attach an elbow (connecting piece) to the wall, and attach a 4″ or 5″ ABS plastic pipe from the elbow to the transition piece on the floor.
- Using sheet metal screws, secure this plastic pipe directly to the subfloor/step through its bend so that it is not visible.
- If you want to insulate the pipe, now is an excellent time to install it (not insulated in the photo above). Attach a transition piece to the floor where your vent is coming out of the wall and attach with sheet metal screws so that it cannot be seen from the floor (this will either screw directly into the floor or into wooden sills, depending on what your home is made of).
- 10. Attach a stainless steel 4″ vent hood and secure with sheet metal screws (not visible in the photo above).
- 11. Seal around all seams where your vinyl pipe attaches to other pieces using high-temperature silicone or stainless steel tape.
- 12. If desired, caulk the bottom of your vent hood to the transition piece on the floor with high-temperature silicon.
- You’re done!
How do I replacing cast iron vent stack, and what type of vent should I use?
This varies depending on the application, so first, cover a few issues and then get into some solutions. It is essential to understand that a standard 2″ cast iron vent pipe has an outer diameter of just over 2.5″, so there is not much room for fittings.
The first thing to be aware of when comparing cast iron venting systems to PVC or ABS is that the Btu rating on the fixture matters. A 2″ cast iron vent pipe will carry less air than a 3″ ABS or PVC because it has a lower insulation value. If you were to try and put the same fixture on a 3″ ABS or PVC, you would have problems with overheating.
As far as venting type, a stack vent is only effective if it goes straight up (i.e., no offsets) and vents to open air (i.e., not in a chase). In most cases, this will be the easiest and least expensive option.
If you need to run a vent horizontally, there are several options: a back-to-back vent, offset vent, or an engineered system. A back-to-back vent is when two 2″ cast iron vents are connected (usually at right angles). A vertical stack is connected to the top of the vent, and you use an offset fitting (usually a 90° street elbow) on the horizontal part of the vent. This would also require a small transition piece on the vertical part of the vent.
An engineered system is when several different options are available depending on what application you are trying to accomplish. This may include a large diameter vent, or several different combinations of 90° elbows, 45° elbows (regular or street types), wyes, and other fittings.
We have several engineered systems available: the Polar White system, which is specifically designed for horizontal runs; the SuperSidewinder™, which is a lightweight and flexible system; and the SquareOne™, which is a very compact system. All of these can be found under the Venting Applications menu on our website and then either Horizontal or Vertical.
There are other types of vents out there, but you will want to pay attention to what they are made from (i.e., galvanized steel) since you do not wish to exposed metal in an exterior wall.
How high can I vent a stack? What happens if I vent it too high?
The distance to the roof’s highest point is usually limited by local building codes but is typically no more than 10 ft above the roofline. If you continue to increase the height of the vent, you will begin to see problems with the vent not being able to push the moisture from the tiled roof.
Can I vent more than one fixture on a stack?
Yes, as long as they are the same size and you have enough rise in the pipe for each additional fixture. You can put up to five institutions on a single stack, but you need to make sure the total rise of the system is at least 20 ft for proper drainage and ventilation.
What is offset distance? How far from my neighbor’s property can I vent my stack?
There are a couple of different options to answer this question so let’s start with what you can’t do. You cannot vent a stack closer than 5 ft from your neighbor’s property line, and this includes the vertical portion of the vent.
Let’s talk about some options to accomplish what you need to accomplish. The first thing is to realize that a standard 2″ cast iron tee (90° or 45°) will have a “stand-off” of 3″. This means your fixture can only go back 3″ from the face of the fitting. If you are looking to get more space between your vent and your neighbor’s wall or property line, you can use an offset tee that has a stand-off of 6″. So if you use an offset tee instead of a standard one, you can go back 6″ from the face of the fitting.
Here’s another great option if you do not mind spending some money to get more distance between your vent and your neighbor’s property line. It is called a “Super Sidewinder™,” and it has an offset ability of 12″ from the surface of the fitting. This means that you can have a stack (a vertical or horizontal vent) go back 12″ from the face of the tee without having to use an offset tee (see picture below).
We hope this information about replacing the cast iron vent stack was helpful, informative, and not too confusing.