Upgrading Older Home Electric and Plumbing Systems

Carl Brahe
Older homes can be a joy to live in but there are aspects of outdated building practices that can be challenging to the occupants. One aspect that must be updated in most homes older than 50 years is the electrical system. Modern living requires most homes to have 200 amp service. We have computers and entertainment devices in every room and high energy consumption electric appliances like ranges, dryers and hot tubs. Fifty years ago most homes could get by with 60 amp service and grounded outlets were not required until the late 1960’s. To bring a system completely up to date may require:

  • New service from the pole to your house if feed wires are not sufficient in size to carry 200 amps.
  • New meter. If your meter is smaller than 200 amps it won’t deliver sufficient power. A system with a 200 amp breaker box and 100 amp meter is a 100 amp system.
  • New breaker box. Most homes require 150 amps of electrical service. Usually, 200 amp service is installed in anticipating of future, unknown needs. The trend toward wireless and low voltage devices may actually decrease future need for electrical service.
  • New wiring from breaker box to all connected devices like outlets, switches, fans and lights. Most devices require grounded outlets, but 2 prong outlets are sufficient for lamps in dry areas. Replacing wiring requires cutting and drilling holes in walls and other building structure. This can be expensive and impractical in an occupied house. Some people leave older wiring in place if it is good condition and serves a purpose where grounded outlets are not required.
  • Consider adding low voltage wiring for lighting when rewiring. LED lighting requires little electricity and can be operated using much smaller wire than conventional lighting. Low voltage lighting and many electronic devices operate on 12-24 volt DC that can be operated on batteries charged by solar, wind or other home generated power supplies.
  • All outlets, switches, lights and other ungrounded electrical devices should be replaced. If it has been determined that the wiring needs to be upgraded the devices attached should also be upgraded.

Electricians are not carpenters and expecting them to do a carpenter’s job will probably be disappointing. If possible have the person who will repair the holes in walls cut them. In many job sites there are running feuds between carpenters and electricians, plumbers and HVAC technicians who cut and drill holes in places that interfere with structural integrity. All the trade workers have special knowledge specific to their trade and may know, or care, little about the work of other trades. Using the correct worker is your responsibility.

The cost of rewiring includes the cost of opening and repairing walls, ceilings and floors as needed. The cost of the electrician and materials for a 100-year-old 1000 sq ft house will vary according to what has to be opened or cut through. Expect to spend from $8000 to $20,000 for a full rewire. Outlets on outer walls are often left ungrounded because of the cost of opening and repairing structure.

Plumbing systems wear out and some materials prove to be defective over time, like polybutylene pipes. You should expect to replace plumbing systems in houses 60 years or older. Both drain and supply systems are likely to need replacement.

Drains in older homes may be made of cast iron, lead, copper, plastic, concrete, tile or even tar paper. Some old drain pipes may function perfectly. If a system is operational and not in danger of failure it need not be replaced because it’s old. Sewer drains can be scoped by a plumber who sends a camera through the inside of the drain to determine if repair or replacement is needed. The camera identifies problems with each and should be done before purchasing an older property.

If you have functional lead drains in your house they probably don’t need to be replaced. If you sell your home with lead drains buyers may be spooked so they are best replaced when you do any plumbing upgrades. Cast iron drains corrode and eventually clog or leak. Tile drains are made of short sections of pipe held together with fiber and lead solder hammered into joints. Tile drains open at the joints as soil shifts and tree roots penetrate. Plastic drains can collapse under ground weight.

Water supply pipes made of galvanized steel or polybutylene probably need replacement. Galvanized pipes corrode from the inside out. The corrosion can clog pipes until water no longer flows. When section of the galvanized pipe are replaced with copper, and connected directly to the copper, electrolysis occurs that accelerates the galvanized corrosion. It’s best to replace all the galvanized piping at the same time. It all has the same age and usage history and will all clog or leak at some point. Polybutylene is dissolved by chlorine and other chemicals used in municipal water systems. If you have PB plumbing replace it immediately if you get water from a municipal system. If you get water from a well, with no chemical treatment, PB plumbing is okay.

Worn out or defective pipes can be replaced by CPVC, copper or PEX. Old pipes are cut out and maybe replaced with CPVC or copper. Sections of pipe are replaced and glued or soldered together as the old pipes are removed. This may require cutting open walls, ceilings or floors. You can expect to pay $8,000 – 10,000 to replace plumbing with copper or CPVC in a 1,500 sq ft home. PEX may save time in installation and materials. PEX is flexible hosing that can be run through walls and floors like electrical wiring, requiring less cutting to expose pipes. PEX is the current preferred material used in high end homes but some worry that time will reveal it to be another polybutylene requiring premature replacement. Replacing plumbing with PEX for the same 1500 sq ft house would probably cost $4,000-8,000.

Replacing both electrical and plumbing systems at the same time costs substantially less than doing them independently. Structure has to be opened and repaired only once and time can be saved for both electricians and plumbers by having a person to coordinate what needs to be opened for each trade and which openings can be shared. If this person is responsible for finished repairs it’s likely that less damage will be done and the results will be better.

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