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The Article Is About Cast-Iron Sewer Pipe Replacement Or Repair (relining).

This article is about aging cast-iron sewer pipes failing due to corrosion — and what can be done about it.  Al’s also provides full-service plumbing maintenance, repairs and replacements for every plumbing component in your home.  Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s is near your home in Plano, TX; Allen, TX; and Frisco, TX.  We service all homes in southern Collin and Denton Counties with no additional travel charge.

Al’s Plumbing, Heating & A/C in Plano, Texas provides maintenance & repairs for all brands of Central A/C, Gas & Electric Furnace, and Heat Pumps.    Additionally, we sell and install new HVAC Systems from American Standard (same company as Trane), Ameristar (same company as American Standard) and Coleman HVAC (same company as York HVAC).

Call Al’s today to discuss any concerns or problems you have with your HVAC System or Plumbing.  We will arrange an appointment at your convenience.

In DFW: Under-Slab, Cast-Iron Sewer Pipes

Descaling, Restoration, Or Replacement

1970's built home

Image Source: ShutterStock

Most DFW homes built before 1975 have cast-iron sewer pipes — and some home builders installed cast-iron as late as the mid-1980s.  The lifespan of cast-iron pipes (under a slab) is around 50 years.   The pipes last longer if chemical drain cleaners have not been used.  Chemical drain cleaners are corrosive — and accelerate the corroding of cast-iron.

Click Below To Learn About Natural, Organic Drain Cleaners For Sewer Pipe Maintenance (reduces the likelihood of clogs). 

Natural, Organic Drain Cleaners

Note: This information is near the middle of the article.  Look for the blue bottle of: “Rid-X”

If You Own A DFW Home Built Before 1980 — It Likely Has Cast-Iron Sewer Pipes

Estimates for how long cast-iron sewer pipes will last vary by who’s doing the estimating. 

40-65 years seems to be a common estimate. 

Our Insight:

  • Cast-Iron Lifespan is notably reduced by the use of chemical drain cleaners.   Every bottle of chemical drain cleaner has the word: “Corrosive” somewhere on the label.  Chemical drain cleaners notably speed the corrosion / rusting of cast-iron pipes.
  • We recommend you never use chemical drain cleaners — because of the danger they pose to you.   If you drop an open bottle of chemical drain cleaner, and it splashes on you — you’re at a high-risk of suffering chemical-burns.
  • Chemical drain cleaners create a chemical reaction to decompose the blockage.  The chemicals mix together to create heat, to help speed the decomposition process.
  • What NOT To Do After Using Chemical Drain Cleaner That Didn’t Work? 
  • If the chemical drain cleaner didn’t work — it’s still present above the clog.
  • DON”T use a plunger or drain-snake after you’ve used a chemical drain cleaner.
  • If you use a plunger or drain-snake after adding a chemical drain cleaner — you risk getting chemical drain cleaner onto your skin or eyes.
  • A plunger or drain-snakes should be used instead of chemical drain cleaners.
  • In most cases, a plunger will remove clogs from sinks or toilets.  Always try a plunger first.
  • If you’ve used a chemical drain cleaner that didn’t work — it’s time to call a Drain-Clearing Service.

Residential Drain Layout & Drain Line Sizes

Click Here To See A Diagram Of A Home’s Sewer Lines:  Diagram Of Residential Sewer Lines

 

  • A DFW single-story home has only horizontal main line(s) under the home.  Each main line has a slight downward slope toward where it exits the home and connects to the sewer line in the lawn.   Horizontal main lines are typically called: “soil branch“.

Click Here To See A Slab Foundation (under construction) With Two Soil Pipe (for 2 toilets) Connections: Foundation With 2 Soil Pipe Connections (the short pipes))

 

  • In a DFW two-story home, a vertical main line(s) comes down (through a wall) — and connects to the horizontal main line(s) under the home.   Vertical main lines are typically called: “soil stack“.

Click Here To See A Soil Stack In A 2-Story Home Under Construction (Soil Stack On Left): Soil Stack On Left

 

  • There is a main/soil line near each toilet.

 

  • The larger the home, the more horizontal & vertical main lines may exist.

Click Here To See A New Sewer Line With Multiple Stacks Locations: New Sewer System With Multiple Stacks Locations

 

  • All the smaller drain lines connect to the main line(s) at various locations.  These sewer lines are typically called: “secondary line“.

Click Here To See Two Secondary Drain Lines Connected To The Main / Soil Line: 2 Secondary Drain Lines Connected To Soil Line

 

  • All secondary drain lines have a “trap” — its purpose is to keep sewer gas from entering the home.   These are typically called: “P-Trap“.

Click Here To See A P-Trap: P-Trap

 

  • The sewer main line(s) also has a trap.  It’s typically called a: “house trap“.  This trap prevents sewer gas from the city’s line from entering the home’s line.

residential house trap U trap in sewer line

Image Source: ShutterStock

SHOWN: “House Trap”

  • Additionally, there are vent pipes running through the roof.  Vents allow the sewer system to maintain equal air pressure.  Without vents — the suction-power (of water moving through the pipes) would pull water out of the individual drain traps.

Click Here To See A Sewer Roof Vent: Sewer Roof Vent

 

  • One sewer main line exits from under the home.  There it connects to the sewer line in the lawn.  The line in the lawn is typically called “sewer lateral“.
  • Where the house’s sewer line exits from under the home, a sewer clean-out is nearby.  In DFW,  the clean-out is located just outside the home’s foundation.   This cleanout is where drain-cleaning equipment enters both the home’s main line & the lawn’s sewer line.

Click Here To See A New Sewer Clean-Out Being Installed: Sewer Clean-Out Being Installed

  • The lawn sewer lateral-line connects to the city’s sewer.

Click Here To See A New Lawn / Lateral Sewer Line Being Installed: Sewer Lateral Line Being Installed

Typical Drain Sizes:

3-4″   Sewer Main Line(s) 

3.25″ Kitchen sink —  this drain line size accommodates a food disposer.
  3″     Toilet — this is typically called: “soil pipe”.
  2″     Washing machine drain line.  Was 1.5″ — but newer washers may drain water too fast for 1.5″ drain line.
  2″    Bathroom (separate) shower
1.25″ Bathtub and bath vanities

There Are Two Ways To Access Sewer Pipes Under The Slab

  • Some plumbers burst through the slab from inside the home.  Then they dig a tunnel to gain access at different locations.  The soil is removed and placed outside the home — then put back one the work is completed.

Click Here To See Where A Slab Foundation Was Burst Through (from inside the house) To Gain Acess To The Plumbing Pipes: Bursting Through The Slab From Inside The Home

 

  • Al’s Plumbing digs a tunnel under the home — from outside the home. The soil is returned under the home once the work is completed.

Click Here To See The Tunneling Method (done outside the house) For Replacing Sewer Pipes:  Tunneling Under The Slab

 

Cast-Iron Sewer Pipe Repair & Replacement

  • The pipes may need to be descaled (discussed below).  Descaling removes built-up corrosion inside the pipes.  The YouTube video below shows descaling as it happens.
  • At some point, cast-iron pipes may corrode all the way through.  If this happens — sewage ends up under your home.
  • There are repair and replacement options for failing cast-iron sewer pipes — we discuss them later in this article.

Descaling

With cast-iron sewer pipes, over time, corrosion deposits form on the pipe’s inner walls.  These deposits are also known as “scale”.   Cast-iron is prone to rusting and corrosion.    If left untreated — the corrosion deposits continue to grow, damage the pipes, and shrink the open area where waste flows by as much as 25%.  This leads to toilet line or whole-house sewer clogs.

Older cast-iron pipes may need to be descaled.  Signs that cast iron sower pipes needing to be descaled includes; foul odors, slow-draining water, or backed up water.  The pipes are descaled using specialized equipment.

Click on the white arrow in the center of the image above to see a cast iron sewer pipe being escaped.  You will see before and after videos showing what occurred.

 

When Cast-Iron Pipes Fail: Replacement Or Repair

photo of PVC sewer pipe

Image Source: ShutterStock

SHOWN: New PVC Sewer Pipe Installation

 

Replacement With PVC Sewer Pipe

Once cast-iron pipes rust through at one location — additional locations will fail in the near future.  For this reason, the entire sewer pipes system is typically repaired or replaced.  The most common solution is replacing the cast-iron pipes with PVC (white plastic).    PVC sewer pipe is highly resistant to chemicals and doesn’t corrode.

PVC Pipe Offers Many Benefits:

Research studies on the expected life of PVC pipe confirmed that PVC life-span to be predicted at 100+ years.  **

PVC doesn’t corrode.  

Some Movement Flexibility:  With DFW’s expansive-clay soil — during rainy periods, some upward pressure on sewer pipes may occur near the outside edges of the home.  During dry periods, the soil will shrink and may not support the pipes as much.   Since PVC has some flexibility — it can accommodate minimal movement.

Water-Tight Joints:  There are a few ways PVC pipes can be adjoined to each other.  All methods provide water-tight joints.  This is very important with DFW’s expansive-soil.

Less Friction Inside The Pipe: PVC Pipes’ smoother interior surfaces increase the rate and speed of waste movement. Slower movement through a pipe increases clogs.

Corrosion & Chemical Resistance: PVC pipes offer excellent resistance to a wide range of chemical and disinfectant chemicals.

Tree Root Intrusion Resistance:  Because PVC joints don’t leak water (like clay sewer pipes in the lawn) — they don’t attract tree roots searching for water.

PVC Is  More Resistant To Heat and Cold:  PVC can handle waste-water up to 140 degrees.

PVC Is Better For The Environment: PVC pips requires less energy and fewer resources to manufacture.  And it’s low weight creates less fuel to transport the pipes.

PVC Pipe Is Recyclable:  PVC pipes are recyclable. In Europe around 80,000 tons of PVC pipes are recycled.

PVC Is Non-Toxic:  PVC pipes can be used to carry drinking water.
** Source: http://responsiblechoice.info/wp-content/uploads/Validation-of-long-life-of-PVC-pipes.pdf

Cast-Iron Sewer Pipes Repair — Cure In Place (CIP) Relining 

These are the typical steps in a Cure In Place (CIP) Cast-Iron Sewer Pipe Relining /  Repair:

Camera scoping of the existing pipes is done — to determine if the pipes are a candidate for relining.

A flexible fabric tube is saturated with liquid Epoxy.

An inflatable tube is inserted inside the fabric tube.

The fabric tube is pulled into the existing cast iron pipe

The inner tube is inflated — to hold the fabric tub in place while the epoxy cures.

The inner tube is removed once the epoxy cures.

 

There Are Two Ways To Create An Opening Where Other Sewer Pipes Connect To The One Being Relined:

Reinstatement: Once the epoxy has cured — a hole is cut in the new lining at the connection.

Gapping – The liner has a gap where other pipes connect to the one being relined. .

 

CIP Pipe Lining — Potential Problems

Generally speaking, there are two main reasons a pipe liner doesn’t fully cure:

  • Water flow within the pipe disrupted the curing process and washed away lining material that had not cured.

FIX:  If lining material did not properly cure (often when lining fails due to water interference) — in only a specific segment of pipe, a sectional point repair can reline the affected segment of pipe.

 

  • The compounds in the liner resin were incorrectly mixed.

FIX:

Attempt removing the failed liner from the pipe.  If the faulty liner was removed — reline the entire pipe.  If the failed liner can’t be removed, the best option may be to — reline over the existing (failed) liner.  This is expected to solve the problem.

Source: https://www.plumbermag.com/how-to-articles/pipe_lining/solving_cured_in_place_pipe_problems
CIP pipe works well on straight pipes with few connections.  This may be the “soil-line” — that connects the toilets to the sewer pipe in the lawn.  The soil-line will be either 3 or 4 inches in diameter.
NOTE: Al’s Plumbing Does Not Provide Cured In Place Sewer Pipe Relining.
NOTE: Al’s Plumbing cannot endorse any brand or vendor of Cured In Place Sewer Pipe Relining — because we don’t have first-hand knowledge or experience with this product or service. 

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The Article Is About Cast-Iron Sewer Pipe Replacement Or Repair (relining).

This article was about aging cast-iron sewer pipes failing due to corrosion — and what can be done about it.  Al’s also provides full-service plumbing maintenance, repairs and replacements for every plumbing component in your home.  Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s is near your home in Plano, TX; Allen, TX; and Frisco, TX.  We service all homes in southern Collin and Denton Counties with no additional travel charge.

Al’s Plumbing, Heating & A/C in Plano, Texas provides maintenance & repairs for all brands of Central A/C, Gas & Electric Furnace, and Heat Pumps.    Additionally, we sell and install new HVAC Systems from American Standard (same company as Trane), Ameristar (same company as American Standard) and Coleman HVAC (same company as York HVAC).

Call Al’s today to discuss any concerns or problems you have with your HVAC System or Plumbing.  We will arrange an appointment at your convenience.