When I first started buying rental properties, a realtor told me about a property that was listed so cheaply it sounded too good to be true.  I rushed to the property so that I could get my offer in first.

It did turn out to be to good to be true.  The house had a crawl space that was less than 12 inches.  And, all the plumbing in the house needed to be redone.  In order to replace the plumbing, all the flooring in the house had to be cut out.

The time to find out about expensive repairs is before you purchase a property.  This article has tips for spotting electrical, plumbing, heat and air, framing, and foundation cracks in OKC rental properties.  

It’s one in a series of articles about improvements to your OKC rental properties.  Here are the other articles:

Keeping the Weather out of Your OKC Rental Property

Cosmetic Upgrades to Your Oklahoma City Rental Property

Kitchen and Bathroom Upgrades for Your OKC Renal Property

Foundation Crack Issues

Slab foundations are foundations consisting of concrete.  The water supply lines and drain lines are set in the concrete.  In old homes with slab foundations (homes build prior to approximately 1990), the air ducts for the central heat and air systems were placed within the slab.

Crawl space foundations are those constructed of wood framing.  Subfloors rest on floor joists in these homes.

Slab Foundation

  • For houses with a slab foundation, foundation problems are indicated by cracks in bricking or interior walls.  The abundance of clays in Oklahoma soils causes swelling from variations in moisture content. This is evidenced by cracks in the concrete slab, brick, walls, or interior doors that become hard to open and close because the walls are shifting.  
  • Not all cracks are signs of foundation problems.  You may also see cracks in the slab, or feel unevenness in the flooring if it’s covered by carpet. 
  • If you suspect a foundation crack, consult a company that specializes in foundation repair.  Get more than one estimate. 
  • Whenever you need to do a plumbing repair, you’ll have to cut concrete to make the repair.  Leaks from water supply lines in the concrete can be hard to locate.  We hire a specialty service to find such problems. 
  • Air ducts in slabs are prone to collapsing or flooding.  If either is the case, they need to be rerouted through the attic space.  Most of the time this means replacing the entire heat and air system.

Crawl-Space Foundation

  • If a home has a craw space foundation, also called conventional foundations, the majority of the weight of the house should be resting upon piers which sit on concrete pads distributed evenly under the house.  Sometimes piers and pads need to be added to correct settling problems in these type of homes. The concrete pads should be at least 2 feet in diameter and 2 feet deep with steel reinforcement. If you jack up the foundation, you may end up cracking some of the interior walls.
  • A stem wall is the foundation on which the exterior walls rest, usually cinder block.  Just because stem walls have minor cracks, that does not indicate a problem in itself.  If it bothers you, you can skim coat the entire stem wall with mortar and paint it with concrete paint. 
  • I once bought a brick home in which one of the exterior walls was bulging outward.  It turned out that termites had eaten away the sill plate.  This is a big deal because the wood framing rests directly upon the stem wall.  It was an expensive repair because I had to have a foundation company jack up the house to lift the weight off the stem wall, rebuild the stem wall and the sill plate, and then rebrick that side of the house.  

  • Be careful about buying houses that don’t have much clearance in the crawl space.  Your service people will need to crawl underneath the house from time to time for maintenance and repairs.  Ideally, you should have at least 18” of clearance between the ground and the bottom of the floor joists, which are the lowest most framing wood under the floor. 

  • Don’t expect perfectly level floors when it comes to houses with a conventional foundation.  This is particularly true for houses built prior to 1940. 
  • Again, if you suspect a foundation problem, consult a foundation specialist. 

Heat and Air System

 I wrote an article about what owners need to know about rental properties with an older central and heat and air system.  

  • If the house is a low-end rental or multifamily property, you don’t need to install central heat and air.  You can use window units for cooling.  For heating, you could use vent-less gas heaters or some type of electrical heat for heating (baseboard, for example). 
  • One of the drawbacks of installing central air systems is that thieves may steal the units and the refrigerant lines for scrap metal in marginal neighborhoods.  If a condensing unit gets stolen, you may consider utilizing the central unit for heating, but installing window units for the cooling.
  • When you have an old heat and air system that is heated by gas, have your heat and air professional make certain the heat exchanger isn’t cracked or rusted.  This is a safety item as they can leak carbon monoxide.  And, have a carbon monoxide detector installed to make certain their aren’t issues.  
  • Make sure the heat/air unit that your contractor installs is adequate to handle the size of the home.  In general, you need 2.5 tons for a 1,000 square foot house, and an additional 1/2 ton for each additional 300 square feet. If they install an undersized unit, they will not be able to keep up with the heat in the summer.  
  • Old wall-mounted gas furnaces installed in the 1950’s are very inefficient. They use far more gas than modern gas heaters. They also pose may pose a safety concern regarding carbon monoxide.


My rule of thumb with plumbing is that when in doubt, replace it.

  • If you need to re-plumb the water supply lines in a house, use PEX which is a flexible plastic material.  It is quick to install (lower labor cost). It is designed to expand upon freezing, so it is good for cold climates.  Check with your local code enforcement to be sure it is acceptable to use PEX in your location.
  • When you have an older house with lead drain pipes, plan on replacing that material because it is notorious for leaks, and most home inspectors will advise that it be replaced. 
  • If you have a small house (1,000 square feet or less) with an attached garage, it’s okay to put the washer and dryer hook ups in the garage. 
  • When you need to conserve on space, your can put the hot water tank in the attic.  But this should definitely not be the first choice because if the lines freeze and burst, you will have a big mess on your hands. 
  • Water supply lines installed in the 1950s and 1960s were most commonly galvanized steel. These should be replaced because they become scaled on the inside. The scaling will lead to low water pressure in the house. It is best to replace them with pex, which is a high-strength plastic material.

  • Water supply lines installed in the 1970s and 1980s were most commonly copper. These will function, but they are prone to breaking when they freeze. This can be a big problem especially if they are installed in a 2nd floor bathroom.

  • Drain lines installed in the 1960s and earlier were cast iron and lead. The lead is prone to leaking. Anytime you have the wall open and expose lead, you need to replace it with PVC. You can leave the cast iron in place if it isn’t leaking, but eventually it will rust through, and will also need to be replaced with PVC.
  • When you have a main sewer line in the yard that needs to be snaked every 6 months because of roots, it’s time to have it replaced.  The maintenance cost and headaches just aren’t worth it.


  • Look in the attic of pre-1960’s houses to determine what type of wiring system is in the house.  When there is knob and tube wiring (cylindrical white ceramic insulators with black wire), you will probably have to replace it. That is fire hazard.  
  • Three pronged electrical receptacles must be properly grounded.  This becomes a big deal if you should sell the house, and it gets a home inspection. 
  • Make sure the kitchen and bathroom(s) have receptacles.  They need to be GFI if it is a new installation.
  • Just because wiring is old does not mean it’s dangerous.  Get a electrician to give you their opinion if you are in question.
  • It’s a good idea to keep trees above or near overhead power lines that feed your house trimmed back.  If you have strong winds or an ice storm, these limbs may come down on your lines which will cause damage which results in expensive repairs.
  • Homes built before 1960 were most built with 50 and 60 amp services, some with fuses. Homes with less than 100 amp service usually are not adequate and will need to be updated to at least 100 amp service.  Fortunately, that doesn’t mean the whole house will have to be rewired. You can find out the capacity by looking in the circuit breaker box to see how how many the amps the main breaker is rated for.  

These were some basic tips for foundation crack repairing. Also foundation crack repairing can be a DIY job as long as the crack doesn’t threaten structural integrity.

Need assistance with your OKC rental property?  Contact OKC Home Realty Services, LLC (doing business as Property Management OKC Plus).

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