Understanding Sewer Repair For Condominium Buildings

Was your condominium or apartment building built before 1985? Are you experiencing regular toilet stoppages and backups, tree root intrusion, or sewer odors? If so, the long-term solution is NOT having your sewer lines snaked every few months.

Property Managers, HOA/Condominium Board Members, and home owners face a real challenge today, especially in areas where a large majority of condominiums are built prior to 1985 such as South Florida. The older the building, the more property managers and board members need to be aware of the infrastructure systems within the building. As we know, EVERYTHING needs to be maintained. This article will highlight the basics that you need to know about your building’s drainage system – how it works, common types of pipes, and what your options are for repair.

Did you know?: The structural integrity of your building’s sanitary drainage system is NOT inspected during 40 year recertification inspections. (source: http://www.miamidade.gov/permits/library/structural-recertification.pdf)

Understanding Your Building’s Sanitary Drainage System

In a multi-story building such as a condominium complex, the sanitary drainage system consists of three main components – vertical stacks, branch lines and horizontal underground lines.Condominium Sewer Pipe Repair

Types of Vertical Stacks

Stacks are vertical lines of pipe that extend from the horizontal building drain under the slab or in the basement up to and through the roof of the building. Although the general direction which these pipes run is vertical, they may be offset or run in a horizontal position on upper floors and still be identified as a vertical stack. In the industry these pipes are either known as soil stacks, waste stacks, or vent stacks depending on the purposes which they serve.

Soil Stacks

The distinguishing factor that gives soil stacks their name is that they receive discharge from water closets and urinals. Clean water fixtures such as sinks and showers may also tie into soil stacks.

Waste Stacks

Waste stacks are tied into clean-water fixtures only – such as sinks, showers, bathtubs, lavatories, and the like. Waste stacks never receive waste from fixtures such as water closets or urinals. If a fixture such as a water closet or urinal was ever tied into a waste stack, it would thereupon become a soil stack.

Vent Stacks

Vent stacks carry no liquids. Their role is to provide airflow through the drainage system so that when water flows through branches and stacks the traps will not be forced by back pressure. The portion of a vertical stack that is above the highest fixture tie in becomes a vent stack.


Rain leaders are vertical stacks in that they extend from the horizontal storm drain or combined sewer drain to the roof. They are called rain leaders because they transport rain water only.

Branch Lines

Branch Lines are offshoots of vertical stacks, like branches of a tree. These branch lines connect toilets, showers, sinks, washing machines, dish washers, etc. to the corresponding vertical stack, which carries waste to the building’s drain underground or in the basement.

Horizontal Underground Lines

Horizontal Lines run underneath the building’s slab, often under common areas such as the lobby and individual ground floor units. These lines are typically 6-8″ in diameter depending on the size of the building. Since sanitary drainage is gravity powered, underground main lines are slightly pitched to carry waste away from the building into the city sewer. The horizontal pipe that receives discharge from waste and soil stacks and is located within the buildings footprint is called the “building drain” and thereafter is known as the “building sewer”.

Common Types of Pipes in Your Building

Here in South Florida the most common pipe used in sanitary drainage in older buildings is cast iron. Next up is clay. Newer buildings however, are often built with PVC. Here is a brief overview of these different piping materials.

Cast Iron Pipes

cast iron pipe crack

Cast iron sewer pipes have a life-use expectancy of 25-35 Years and then they begin to develop cracks and channels. (photo source: https://www.flickr.com/photos/jdickert/)

Cast iron piping is still by far the most common material used for sanitary drainage in multi-story buildings such as condominiums and apartment buildings.

Here are some key advantages of cast iron pipe that come into play:

  • Cast iron drainage pipes offer durability and can support 4,877 lbs per linear foot.
  • Cast iron piping reduces noise due to its density, which is an important selling point for condominiums, apartment buildings and hotels.
  • Fire-resistance is another key factor of cast iron pipes as they will neither burn or contribute to the spread of fire.

The main disadvantages include:

  • Cast iron piping is expensive.
  • Cast iron has a relatively short lifespan of 25-35 Years (in South Florida).

After cast iron’s expected life-use of 25-35 Years in South Florida, the pipes can be expected to begin developing channels in horizontal lines and cracks in both horizontal and vertical lines. Buildings in close proximity to the ocean experience accelerated cast iron pipe deterioration due to the salt in the air which is pulled down the vent stacks and the fact that the underground cast iron pipes are often submerged in salt water twice a day with high tide. Salt and cast iron is a corrosive combination. Cast iron piping, however, is often still favored over PVC in condominium applications due to the advantages listed at the outset.

Vitrified Clay Pipes

clay sewer pipe repair

Vitrified clay piping dates back to 4000 B.C.E., however is rarely used today. – – (source: http://www.freeimages.com/photographer/algojo-43026)

Clay sewer pipes are most common in historic homes and buildings. Vitrified clay sewer pipes have been in use since ancient times with the earliest known example dating back to Babylonia, 4000 B.C.E.

Advantages of vitrified clay piping include:

  • Durability
  • Chemical resistant material for sanitary drainage

However the disadvantages of clay pipes include:

  • Clay is very susceptible to tree root intrusion as the porous outer surface is easy for roots to attach to
  • Very heavy and hard to cut
  • You most likely will not find it in your neighborhood home improvement store.

Source: http://www.sewerhistory.org/grfx/components/pipe-cly1.htm

PVC Piping

PVC sewer pipes

Studies suggest that PVC pipes have a service life of 100 or more years. (source: https://www.flickr.com/photos/fontplaydotcom/)

Starting in the 1970’s PVC pipes began to be installed in mass quantities. Cast iron proponents would say that not enough time has yet elapsed to determine the service life of PVC, however, studies suggest a 100-year or more lifespan for PVC. (source: http://www.plasticsnews.com/article/20140515/NEWS/140519940/study-100-year-life-for-pvc-pipe-conservative).

PVC versus Cast Iron has been a hot topic in the pipe manufacturing industry for years. However certain advantages are clear and include:

  • Longevity
  • Cost efficiency

However certain disadvantages are clear as well and include:

  • Non fire-resistant, additional fire-stopping measures required upon installation.
  • Carcinogenic fumes when exposed to excessive heat.
  • Not as strong as cast iron.
  • Noisy water transportation (not ideal for multi-story residential buildings such as condominiums and hotels).

Conventional Sewer Replacement

Conventional Pipe Repair

Conventional pipe replacement requires access to the old pipes by means of trenching floors and tearing out walls.

Conventional pipe replacement is a MAJOR undertaking for condominium buildings. Now that you understand where the pipes run in your building and know the typical lifespan of cast iron pipes, you may have an idea what would be involved with replacing those pipes traditionally, tearing out walls, tearing out custom floor finishes and slab, relocating tenants, extensive mess, expense, etc.

Trenchless Pipe Lining Sewer Repair

Pipe lining – also known as Trenchless Pipe Lining, C.I.P.P. (Cured-In-Place-Pipelining) – is the process of repairing sewer pipes without digging or destruction. In a nutshell, an epoxy saturated felt liner is inserted into the pipe which is inflated, cures in place and leaves behind a brand new pipe.


The advantages of trenchless pipe lining include:

  • Sewer repairs to be made without tearing out walls or floors
  • Saves your building 30-40% of the cost of traditional sewer replacement
  • Trenchless sewer repair allows for residents to stay in their home during repairs
  • Can be completed in a fraction of the time involved with traditional sewer replacement.

In South Florida, we deal with many condominiums built as far back as the 1960s that have cast iron and have not yet set aside a budget for repair. If your building was built before 1985, you need to start budgeting for pipe repair now to avoid dishing out costly assessments in the case of sanitary sewer failure. Your first step to diagnosing the condition of your sanitary sewer would be a comprehensive video inspection. If you are within our service area in Southeast Florida we would be happy to provide you with the needed assistance. Call Pipelining Technologies today at 561-412-4234 or click here to contact us!