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Home Inspections Homes built in the 70’s

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Home Inspections Homes built in the 70’s

So, what should you be concerned about, and checking carefully, when Inspecting a ‘70s era home? Here’s our list:


Floor Plan - The average home was smaller, with about 25% less square footage than new homes today. The master bathroom had become standard, but it was not much bigger than the one in the hallway.


Also, the split floor plan, with a master bedroom suite on the opposite side of the house, was not yet in the game. Look for it behind the last door at the end of the hall.


While you can add more square footage by enclosing a porch or building an addition, gut and remodel the kitchen, or even knock down a wall to open up more visual space, moving rooms around is prohibitively expensive, so be sure the basic layout suits your lifestyle.


Energy Efficiency - Although the oil shortage of the late ‘70s dropped the speed limit to 55 mph, caused millions of Americans to take gas mileage seriously, and compact cars sales boomed, the energy efficiency of homes was not yet a priority. Wall and attic insulation R-value was just over half of the standard today and windows were un-insulated single-pane. The concept of carefully sealing the envelope of the house from air leakage was also not a big concern. 


Some of this may have been fixed over the years, but it’s a good idea to take a peek at the condition of the insulation in the attic if you can, observe how well the doors and windows are sealed, and ask the seller to provide a few recent utility bills. Some homes from this era are surprisingly energy inefficient.


Foundation and Exterior Walls - Earlier era homes were built on a stem wall or piers, but 1970s homes were concrete slab-on-grade, with a thickened edge that served as a foundation. A site dictates the foundation type to a certain extent, however, and sloping sites often required a combination of a concrete block stem wall on the more sloping part of the ground under the home and slab-on-grade on the flatter areas of the site.


Over the 40-plus of the home’s existence, soil erosion will take its toll on a sloping site as the soil slowly migrates downhill. Look for tell-tale stair-step and diagonal cracks, especially on the down-side of slopes, indicative of settlement, along with areas where the base of the foundation is beginning to become exposed. Other factors, such as expansive clay in the soil under the home, can also cause foundation distress over time.


Any older home will accumulate a few cracks from minor settlement and the natural expansion and contraction of the structure through the temperature changes of the seasons, and they are not a reason to be concerned. What you should look for are cracks larger than about 1/8” across (that you easily can stick two quarters into) and/or that have differential (one side is kicked-out higher than the other). Differential is usually the result of significant movement. 


If you find signs of structural problems, it is not necessarily a reason to abandon a prospective house. Your home inspector can evaluate the defects further and give you insight into how severe the problem appears to be, along with referring you to a foundation contractor for further evaluation, if warranted. To learn how to evaluate the purchase of a house with known structural defects, see our blog “Should I buy a house with structural problems?”


Plumbing - Galvanized steel water supply pipe was often used for 1970s homes but, unfortunately, it has a 40 to 50 year lifespan due to rust buildup—which is approximately the age of these homes. If the house has galvanized pipe, you may see some visible corrosion, especially at the pipes near the water heater. But the real problem is on the interior surface of the pipes, which releases little flakes of rust that build up behind behind sink and shower faucets, severely reducing water flow. Eventually, rust eats through the pipe and it begins to spring leaks, often under the floor slab. Also, many insurance companies will not write a homeowner’s policy on a home with galvanized pipe, or they will require a plumber to certify that the pipe is in good condition.  


Because a water heater can last anywhere from 10 to 25 years or more, it has already been replaced once or twice, so the age is variable. Your home inspector can tell the exact age of the water heater from the serial number later, or you can jot it down and determine how old it is yourself at our blog “How do I decode the water heater serial number to figure out the age?”


Electrical - The good news is that all homes built in the 70s have modern 3-slot, grounded receptacles and the electrical system is very similar to today’s equipment. GFCI (Ground Fault Circuit Interrupter) shock protection for bathroom and exterior outlets was not required until the very end of the decade, so most homes won’t have it unless installed as part of a later remodeling. To learn more about GFCIs, see our blog post “Why does that wall plug have push-buttons in the middle?”

Aluminum wiring was substituted for copper in the early 1970s, during a copper shortage, and it was promptly discovered to be a fire hazard. Although several repairs were approved afterwards by the building code to the wire connections where the fires were starting, replacement is considered the only sure cure. Virtually all of this problematic wiring has been replaced, and we rarely see single-strand aluminum wiring anymore, but there is still some out there.


It’s important to note that only single-strand wiring used for smaller household circuits was a problem, and multi-strand aluminum wiring made from a different aluminum alloy is still in use today and code-approved. Because checking for aluminum wiring is usually done by opening the electrical panel, it’s best to leave it to your home inspector later to verify that the wiring is okay.


So find the electric panel during your house showing, open the door and look inside. If it says Stab-Lok between the two columns of breakers, you should consider replacement a priority if you buy the house.


HVAC - This system has been replaced at least once by now. Because the components of a heating and air conditioning system may have been changed out at different years and evaluating the condition of the ducts requires crawling around the attic, wait for a thorough evaluation by your home inspector on this. But definitely take a look at both the interior and exterior units. If they are rusty and look really old, they probably are.


Roofing - The average life expectancy of a roof is 20 years and, since the home is now 40-plus years old, ideally it has replaced for the second time recently. To learn what clues to look for when trying to determine the condition of the roof, see our blog “How can I tell if the house needs a new roof?” Your home inspector will take a look at the roof up-close, but there’s plenty you can observe looking up at it from the yard.


Asbestos and Lead - Both were banned by the government in 1978, although not much lead paint was used in the ‘70s anyway, and asbestos was mostly limited to popcorn ceilings and some fireplace flues. Testing for lead and asbestos can be done later, as part of the home inspection, if you are concerned about these contaminants. To find out more about lead contamination issues in older homes, see our blog “I signed a lead paint disclaimer in my real estate contract. What’s that about?”


In Minneapolis, Saint Paul contact Inspections Plus for complete home inspections for any age homes.

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