Is a slab foundation a bad choice?

Image of a slab foundation being prepared.

Is a slab foundation good or bad?

Houses used to be built directly on the ground, right on the dirt, grass, or whatever else was there. Eventually, pier & beam came along that raised houses up using blocks, bricks, logs, and even car parts like transmissions. Then, the construction industry started building houses with slab foundations

Slab Foundation vs Pier & Beam

When considering slab foundations vs pier and beam today, you’re likely not going to find car parts and other odd things under a pier & beam house. That has graduated to cylinder blocks, cement piers, and some wood for leveling. 

A pier and beam house is typically found to be a stable foundation, and in some areas and situations, it is the preferred and recommended option. However, over time a pier and beam does tend to deteriorate as the ground shifts. Repairing a pier and beam is cheaper and easier compared to repairing a slab foundation. 

Real estate experts advise their clients to consider what they want for their preferred home – things such as: 

  • Basement
  • Crawlspace
  • Slab

Each provides a bonus, depending on what your plans are for your home. Things to be considered in making this decision would include: 

  • Lot grading or undisturbed soil
  • Drainage
  • Landscaping plans

Some advantages and disadvantages of having a slab foundation include:

  • A slab foundation or a basement will require excavation before building. This adds to the cost of the house. 
  • A slab foundation, in good condition, is less susceptible to insects, pests, and vermin entering the house. 
  • A slab foundation can make it difficult to repair plumbing that runs through the concrete slab.
  • A slab foundation helps with insulating the house. 
  • A slab foundation house is closer to ground level, minimizing the needs for steps. 

What are some slab foundation benefits?

In addition to the items we listed above, other advantages of a slab foundation house are the quick dry and cure, ready to build it offers, usually within a day. Also consider:

  • A slab foundation is strong and durable. 
  • A slab foundation is less likely to flood because it directs rainwater away from the house. 
  • A slab foundation is less likely to have mildew and mold issues because of this directed rainwater. 
  • When choosing between a slab foundation and a basement for your home, the slab foundation will typically max at $20,000, which is about half of what a basement will cost. 

Why is slab foundation bad?

Well, it isn’t. Not necessarily. What humans learned from building homes directly on the ground were that three things were needed: 

  1. The structure needed better support
  2. Groundwater needed to be redirected
  3. A barrier was needed against soil vapor and water

Once those three things have been addressed, you’re good to go with building the walls, roof, and other features. A concrete slab foundation is the most common and popular option used today in construction. Some preparation is required for a slab foundation, like a concrete footing 24 inches below the projected finish grade. 

After that, two layers of concrete block are placed on top of those footers. The internal plumbing piping is installed next. Next is the rock filler, and then four inches of concrete is poured. 

The main disadvantage of a slab foundation is that it can require expensive repairs. As the ground here in Texas shifts, slab foundations can crack or sink. As a slab foundation cracks or sinks, it can damage pipes, and getting those repaired can be expensive because of the jackhammering required to get to those pipes. However, today builders are using PEX plumbing, which has proven to be better in not breaking. 

Another disadvantage of a slab foundation is the lack of protection during inclement, severe weather events. With enough rainfall, the water can find its way into your home easier than it would with a pier and beam. 

How do you fix a crack in a slab foundation? And can a slab foundation be fixed?

Can a slab foundation be repaired? Yes – when a foundation issue is discovered early enough, it can be brought back to new with any of the following methods: 

  • Foam Jacking: This is a repair method that uses a polyurethane foam to bring a setting foundation back to grade level. It is installed in a checkerboard pattern, after which holes are drilled into the slab. Then this high-density foam is injected under the foundation, expanding and raising the slab up while filling empty spots. 
  • Masonry Patches and Sealants: If a foundation cracks because of shrinking soil, the cracks are usually around corners. Even though this isn’t considered a structural issue, it needs to be addressed so more damage isn’t done. This process is done with hydraulic cement, much like mortar, to create patches and seals. 
  • Epoxy Resin: This is like the use of a hydraulic cement sealant though a few more steps are required for strengthening. It can be injected or poured, depending on which method is best for the situation. 
  • Slab Jacking: If you notice a sinking foundation, you will typically discover the original dirt was not packed right during construction. This repair process is done by drilling holes into the slab foundation and adding a grout-type mixture that raises the concrete. 
  • Piling: There are different styles of piers and pilings used to repair foundations. This is an invasive method but it also lasts longer. 

Other methods for slab foundation repair include steel piers, helical piers, and spot piers. The contractor you choose to work with should advise you of the options best for your house along with the pros and cons of each. 

Close-up of metal framework being prepared for slab foundation.

In Closing

Just how long do slab foundations last? We’re going to estimate a lifespan of up to 100 years, and probably longer, if that slab foundation was prepped and installed correctly. So, is a crack in a slab foundation bad? Absolutely! With even a small crack, the foundation of your home is susceptible to more damage. This will not only allow insects, pests, and vermin inside your home but can also make the foundation meant to keep the walls and roof stable weaker.

Walls lean, roofs collapse – the possibilities of what can happen at this point are endless the longer the slab foundation isn’t repaired. If you suspect damage to your foundation, or you need help with a slab foundation in Dallas-Fort Worth Area, TX  or need repairs ASAP, contact the Solid Rock Foundation Repair team by calling 817-400-7625.