There is a science behind having vent pipes installed into your sewer and water waste drain system. As the waste moves through your waste lines, gravity is pulling it downward and out of your home. Without an air intake, the moving waste would create a vacuum which would cause it to stop moving through the system, as it is being pulled toward the sewer. This venting system is designed to allow multiple drains throughout your home to use this airflow from the vent to release any back pressure. Because of these reasons, it is very important that your vent pipe does not get clogged by birds nests, or any other obstructions, to prevent your sewer drain system from backing up into your home.
Step 1 - Locate your Vent Shaft on the Roof
In many cases the strange white pvc tube that sticks out the roof of your house is actually your vent pipe. In some homes, it actually sticks out of the wall, which is generally on older types of ranch homes or one story flats. In either case you want to be sure that nothing gets into these pipes and clogs the airflow in the system from getting through as it should. The best way to do this is to install a vent cover over the top of the actual shaft, and you will want to ad this to your yearly house inspection and maintenance list.
Step 2 - Assemble the Vent Cover
The cover on your vent pipes could be worn or contain blockage, which can effect your system. If you are installing a new vent shaft system you are going to want to get a cover on this before it is installed into the main drain lines to prevent blockages. The top of the unit simply needs to have a vent cover installed, and you do not want it to protrude more than 6 to 12 inches above the roof. You should have several caps for the 2 ends of the vent t-bend, which have securing pins or snaps embedded on the inside to hold in screening. The screens should be inserted and then locked into place so they can not easily come loose. Once you have the screens installed they will lock into an unmovable state once they are screwed into position on the t-bend. This will prevent bugs from getting in and clogging the lines as well as birds and other neighborhood creatures, such as rats, mice or squirrels.
Step 3 - Install the Vent Cover
Once you have the vent cover built, you can then install it onto your vent pipes where it comes out of the roof of the home. All you need to do at this point is to add the pvc sealant to the inner lip of the pipe and slide it onto the vent shaft. A good thing to keep in mind here, is to make sure that the vent openings are pointing away from high wind directions. This will vary by your geographical location, as in some areas winds can come north to south or east and west.