Pier And Beam Versus Slab Foundations in the Dallas Area

By
Real Estate Agent with Texas Urban Living Real Estate 0596165

Dallas has a rather unique mix of homes with slab (also called "slab on grade") and pier and beam foundations.  The majority of pier and beam foundations in the Dallas area can be found on older homes built up to the 50's and early 60's. 

Pier and beam foundations are still built today, but usually only by a few custom builders and contractors.  Most large production builders use only slab on grade, but most of them incorporate this with post-tension cables, which helps to increase strength and durability on Texas soil. 

The soil in the Dallas area tends to be very expansive because it contains a good deal of clay, which expands and contracts depending on the amount of moisture.  Hot, dry conditions in the summer can lead to foundation problems on both pier and beam and slab foundations, but are generally more common with slab.

Here are some advantages and disadvantages to both that may be worth considering.  Every house is built different, so these are not the only factors to consider.  As always, consult with a licensed structural engineer if you have specific questions about foundations.

 

PIER AND BEAM FOUNDATIONS

Advantages:

  • Allow for easy access to service or relocate plumbing, electrical and other mechanical items provided there is adequate crawl space under the house.   
  • In many cases, foundation issues with pier and beam can be both less common and also less expensive to repair than slab foundations as long as it was initially designed and built properly.   I have seen a few instances where an inexperienced contractor attempted to build a pier and beam foundation that failed, and the result wasn't pretty.  If you plan on building a home with a pier and beam foundation, make sure the builder and their contractors have experience with pier and beam foundations and can provide references. 
  • Some othe remodeling projects may be easier to construct on a pier and beam.  It depends on what you're doing. 
  • It may be easier to prevent and detect termites in pier and beam homes since they must tunnel along the concrete piers and/or wall in the crawlspace of a pier and beam foundation before reaching wood (assuming no wood is touching the ground).  Check to make sure the piers have termite guards that can make it extremely difficult for termites to build tunnels up the concrete piers.  And since the tunnels are normally visible along the exterior concrete walls as well, it can make them easier to detect overall. Termites can tunnel through cracks as small as 1/32 of an inch, which can make it harder to detect in slab foundations, especially if the termites tunnel through a crack directly into a part of the house that is not accessible or viewable. 

Disadvantages:

  • Pier and beam foundations must be vented properly to avoid excessive moisture.  The moisture can sometimes lead to mold, rotting wood or a musty smell if not vented properly.
  • Broken vent screens can allow bugs and rodents to get under the house, which can be a real pain (especially if a rodent happens to DIE under the house).  The screens can be repaired, but rodents and bugs can easily chew through the older screens.
  • Proper ventilation of pier and beam foundations can lead to colder floors in the winter, especially if there is no insulation under the floor. 
  • The floors can creak and move in some cases.  Large items of furniture, especially items like China cabinets that contain movable, breakable pieces can rattle when someone walks or runs by.  If you have young children (especially if they're HYPERACTIVE) or even large pets, it's a good idea to test the stability of the floor. 
  • Pier and beam foundations are still prone to movement and foundation problems.  Pier and beam homes can sometimes flex vertically, which may cause areas of the floor to appear higher or lower than surrounding areas, which can cause problems with flooring, etc. Tile floors can break and become loose when pier and beam foundations flex.
  • Risk of pipes bursting in hard freezes, especially if vent covers are missing.  Home owners should make sure all vents are covered during sub-freezing weather. 

 

SLAB FOUNDATIONS

Advantages:

  • They are generally LESS EXPENSIVE to build than pier and beam foundations. 
  • The floor generally feels more SOLID than pier and beam in many cases.  No shaking/vibrating of the floor means no rattling furniture when you walk by.  Thus, they may also be quieter than pier and beam foundations.
  • Recent improvements in technology and engineering of post tension slab foundations have led to some significant improvements in quality, design and durability, especially on Texas soil, which very expansive because of both the high clay content and the hot, dry climate.  The earliest that most builders began using post tension cables in foundations was around 1999.  Foundations built with post-tension cables are usually easy to spot by looking for the patch holes at the base of the foundation.  Once the concrete in the foundation dries, the cables are tightened and a small amount of concrete is applied to cover the hole. 

Disadvantages:

  • Foundation repairs on slab foundations can be more expensive than pier and beam in many cases. 
  • Plumbing repairs under the house can be extremely expensive and difficult repairs because they are hard to detect and can require parts of the foundation to be jackhammered and rebuilt in order to access the damaged plumbing in some cases.
  • Can have a higher tendency to crack since they only touch the top level of the soil, whereas pier and beam foundations can go deep into the soil and can even anchor on bedrock in some cases.   Some engineers design slab foundations with deep grooves in the ground to help guard against movement.
  • Relocating electrical and plumbing can be more expensive and difficult with a slab than with a pier and beam foundation.
  • Some remodeling projects may be harder to accomplish on slab foundations.  
  • Termite treatment can require holes to be drilled through the floor and foundation, which may have to be repaired and could possibly damage the look of the floor, depending on the material. 

There are many things to consider when deciding what foundation best fits your needs and wants.  As always, consult a licensed structural engineer if you have specific questions or suspect a problem with your foundation. 

Proper care of a foundation, regardless of type, is essential to avoiding expensive repairs. The Foundation Repair Association performed a study in 2000 and found that the most common reason for foundation problems was lack of maintenance.  And since Texas has very expansive soil and also a hot climate, it's important to keep the area around the foundation properly irrigated. People new to the Dallas area often don't realize this and fail to maintain their foundation properly.

Most foundation experts I've spoken with recommend watering the foundation with soaker hoses for 15-30 min per day at least 3-4 times per week during the hot, dry season.  It's important to keep the hoses around 18-24 inches away from the house to avoid water pooling under the foundation and causing additional problems  Soaker hoses used in conjunction with electronic hose timers can be a good way to ensure your foundation receives a steady dose of evenly distributed moisture around the perimeter.  

And here's a great link to an article about foundation maintenance from foundationrepair.org that covers many details about proper maintenance and care of foundations.

 

 

 

Posted by

John Jones, Realtor(R)

Texas Urban Living Real Estate

www.homesourcedallas.com

5706 Greenville Ave Suite 210

Dallas, TX 75206

Dallas, TX Real Estate and surrounding areas of Richardson, Plano, Addison, Frisco, Carrollton, Farmers Branch, Garland, Allen, Irving, Rowlett, and Rockwall.

Dallas, TX neighborhoods and subdivisions of Lake Highlands, White Rock Lake, Lochwood, Eastwood, L Streets, M Streets, Hollywood Heights, Lakewood, Coronado and Gastonwood, Forest Hills, Lochwood, Eastwood, and Preston Hollow.

Copyright 2008-2013 by John Jones, All Rights Reserved.  You may reblog or republish with links back to this post. 

* THIS ARTICLE WAS ORIGINALLY PUBLISHED AT http://www.homesourcedallas.com  *

 

 

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Rainmaker
1,386,319
Donna Harris
Donna Homes, PLR - Austin, TX
Realtor, CDPE & ASP - Hill Country Lakeway Austin

I always hate walking in a house on pier and beam because I feel I could fall right through the subfloor and it's also a more hollow sounding step.

Aug 10, 2009 08:05 PM #1
Rainmaker
377,297
Ricki Eichler
Century 21 Lee Real Estate - Ingleside, TX
Broker,GRI,ABR, - Your Coastal Bend Home Source

I dont like pier & beam homes either.  I like the feel of a slab floor. You can also go deep on a  slab footing if you need to.

Aug 10, 2009 08:38 PM #2
Rainer
639,033
Carl Winters
Canyon Lake, TX

John: As an inspector I can tell you I don't like crawling under a pier and beam for allot of reasons. In this drought that we are having here in TX you never know what you mgiht meet up with, like sneaky snake.

Aug 10, 2009 09:30 PM #3
Rainmaker
71,578
John Jones
Texas Urban Living Real Estate - Dallas, TX

Donna - yes i can see how it would feel to someone who wasn't used to them, but i grew up in several of them so it's what i'm used to. 

Ricki- yes you can go deep, but how many of the slabs in existence are deep?  not many.

Carl - yes i came face to face with a dead rat under my house once.  it was awesome.  we made friends, took long walks in the park and watched movies together. 

actually the truth is i puked and couldn't eat for a day or two.  but i'd still take a pier and beam over a slab any day.  I could see how it would get old as an inspector.  you must have a tough stomach and don't mind getting stung and bitten. 

Aug 10, 2009 11:20 PM #4
Rainer
1,025
Chris Soiset

Contrary to the list above, ventilating a pier and beam foundation is not necessary, and in typical southern climates, it is unwise.  A far better design is an encapsulated crawlspace, which incorporates a vapor barrier on the ground and sides of the grade beam, and insulates the interior wall of the grade beam.  This design, which can be incoporated after construction on any age house, uses far less insulation than if the subfloor is insulated, eliminates vapor condensation problems on the subfloor (a summertime issue that leads to rotting joists and subfloor), provides superior insulation, effectively eliminates pest problems from below (the attic is a different matter), and makes a very nice, clean crawlspace to work in. 
Re the first comment, if you felt as though you were going to fall through the floor in a pier and beam house, you must have been in a home built in the 20's, or built very poorly.  Floor solidity is a result of deflection and vibratory period.  If you walk on a floor with an undersized joist/girder/subfloor system, it will feel hollow and springy.  I suggest reading this:  http://www.woodbywy.com/products/software/tj-pro-rating-system/

Slabs are chosen by builders for a single reason:  they are cheaper.  Only since the mid-nineties have slabs tended to have been constructed properly, with extensive subgrade replacement and stabilization, and adequate post-tensioned design.  Almost all high end custom homes, especially those built where the expansive clay layer is more than a few feet deep, are built on pier and beam foundations.  They are simply more comfortable, and for many, being above grade is simply a better living experience. 

One of the most important advantages of a pier and beam home is that the utilities are easily accessible.  Updates and repairs are a cinch, especially if the height is adequate.  Additionally, when a drain or supply line evelops a leak or ruptures, it doesn't create the serious, immediate problems that it does under a slab, and it can be accessed and repaired without having to tunnel in from the outside, or run a concrete saw in the middle of the house to access it.  Additionally, unless the subgrade, water or sewer line, and slab penetration are carefully designed and constructed, slab movement will rupture the line where it penetrates the slab. 

Slab homes are far more "disposable" than a pier and beam home.  They simply won't be around as long, on average, because they are not worth the trouble of oong-term maintenance and repair (and you certainly won't have people restoring slab homes after 80 years) and, typically, they are built to a lower standard generally because the primary factor since they became popular in the early sixties was $/sqft.  You can get a lot more space for the same money if you build the house on a slab, and use other low cost building methods and materials.  But the house will last 50 years anyway, and that is the "design life" of the structure, so there is no regulatory fuss.

Anyhoo, as a structural engineer, inspector, and obsessive home improver and building science researcher, I'll take a pier and beam over a slab any day.

Mar 21, 2013 08:10 AM #5
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Rainmaker
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John Jones

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