Disadvantages of Concrete Basement Walls

Concrete can crack and leak anywhere

concrete-foundation

While historically preferable to other traditional building materials, concrete has many important drawbacks, such as overall mass, installation time and poor insulating properties. It is extraordinarily heavy and requires a labor intensive and time-consuming installation process. Achieving appropriate insulation using concrete is difficult. By itself, concrete offers very little resistance to heat flow. For example, a 7-inch thick slab of poured concrete has the same R-value as a single pane of glass (R-1.5). An additional difficulty is that concrete walls often crack due to shifts in the ground and water pressure, creating leaks and allowing mold and mildew growth. Even without cracks, concrete is porous, typically creating basement living areas that are damp, unpleasant, unhealthy environments.

Cast in Place Poured Concrete Walls

concrete-walls

  • Require multiple steps for installation
  • Several trips to the jobsite with heavy equipment
  • 200 man hours to install
  • Extensive form work including transport, placing, oiling, stripping, cleaning and removal
  • Bracing is needed to resist soil loads prior to the installation of the floor system.
  • Concrete walls are over designed for holding the weight of a house, yet are challenged by backfill loading.
  • Concrete needs to be damp proofed to keep out moisture
  • Vapor barrier systems that work well are extensive and expensive
  • Concrete itself has little inherent R-value – insulation is applied in multiple steps
  • Curing process is affected by the elements – steps must be taken to protect integrity in colder temperatures including covering, adding calcium chloride and using heated water

Insulated Concrete Forms (ICFs)

  • ICFs must be covered on the interior with drywall prior to occupancy because they do not satisfy fire code.
  • The exterior of ICFs requires some sort of covering to protect the expanded bead polystyrene foam from outdoor elements.
  • Homeowners recognize the benefits of properly insulated basements and are willing to pay for those benefits. ICFs have ~4.5% market share even with the many drawbacks and high cost of the system.
  • ICFs typically use the same amount of concrete as conventional walls, requiring additional raw materials adding to overall cost
  • ICFs themselves offer no structural benefit, relying on steel for reinforcement as with conventional concrete walls
  • Each ICF system is unique with a host of specialty pieces and parts. Lacking the mechanical chase, all mechanical systems and openings must be pre-planned and precise.
  • Extensive bracing is required with ICFs – adding to labor cost.

Insulated Concrete Forms (ICFs)

Concrete block foundations have been essentially replaced by poured walls in the foundation market in the past 5 years due to high labor costs, and they struggle more so to resist lateral forces of backfill loads without cracking or breaking.

  • A concrete block (concrete in general) is a porous material requiring extra measures to attempt to keep the moisture out.
  • Concrete Block Walls, Poured Walls and ICFs do not have a recurring stud cavity, which has proven its value in construction for the placement of necessary mechanicals (wiring, HVAC, electrical boxes, plumbing, additional insulation, etc). Wood framing is typically applied to concrete in a secondary step to create the mechanical chase. Installing wood adjacent to moist concrete is problematic.
  • The concrete system is challenged in promoting a healthy living environment – being a porous material, vapor transfers freely – when moisture contacts a food source such as wood or the paper facer on drywall, and living space temperatures reach 70 degrees, mold and mildew thrive, creating a less than attractive living environment.

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