Cracked Slab on Post Tension Foundation - Forum. Hi,I am building a new home in Sigar Land TX, near Houston. The foundation was poured on 7/8/0.

This crack is about 1/2 mm thick and is visible to the naked eye. It is visible on the 2 sides as far as I could dig the dirt about 1 feet deep and probably it goes even deeper.

It is also visible on the surface of the slab. After about 1. 0 days the post tension cables were pulled to tension and the cracks appear to have closed a little bit, but still visible.

Is this crack normal in post tension foundations in this area and will I have any problem with this crack in the future. The builder says that this is normal and not to worry about it. But from the appearance of the crack I think that the slab has cracked in 2 and that this is a serious problem. Any comments are appreciated. Thanks in advance.

Stop Errors that Cause Cracks in Post- Tension Slab Foundations. Slab- on- grade foundations are one of the most popular types of foundations in the U. S. They're quick and inexpensive to build and are great in southern climates where the freezing depth in the soil is shallow. In these climates, slab- on- grade foundations work well, as long as the slab is built to a good standard of quality and performance. Typically, the largest concern with slab- on- grade foundations is cracking. Concrete naturally experiences some cracking as it shrinks during the curing stage. These natural cracks are known as shrinkage cracks.

Post-tensionmg enabled the lifting weight to be reduced and the.

Shrinkage cracks appear as a displacement or separation in the surface of the concrete and are hard to prevent. Shrinkage cracks aren't detrimental to the performance of a slab, but they can be unsightly and cause cosmetic damage to interior floor finishes.

Concrete can also experience cracking when certain soil conditions are present. These soil conditions, which we'll discuss in a minute, require additional measures to ensure the quality and performance of the slab. One such additional measure is to reinforce the slab through a process called post- tensioning. Post- tensioning compresses concrete, enabling it to resist both shrinkage cracks and cracks caused by difficult soil conditions. Steel strands are run through the concrete in a grid pattern. Each strand is housed inside plastic sheathing that protects the steel from corrosion and allows it to move during the stressing operation.

Each strand is gripped by an anchorage on each end. The combination of the strand, sheathing, and anchorages is called a tendon. As each tendon is pulled tight, the steel stretches and is held in place by the anchorage, keeping the tendon tensioned for the life of the foundation and helping the slab resist forces that act to pull it apart. What can cracks cost? The last thing you want to throw away money on is a defect in the foundation. Defects such as slab cracks can be costly to repair after construction. Removing the interior floor finishes to make repairs to the slab is both expensive and time- consuming.

1. I had a call this morning from a prospective client who was concerned about cracks in the concrete foundation of the home they were building. Most often the cracks.
2. The large forces required to tension. This crack-resistance also allows individual slab.
3. TAB.3-13 Post-Tensioning Terminology (PTT). Stress bar High strength steel bar used in post-tensioning conforming.
4. Hairline Cracks in Post Tensioned Slab Y3392.
5. Cracked Slab Foundation. What is a 'cracked slab foundation'? Most concrete slab foundations were and are built with steel rebar or post tension cables for strength.
6. Hi, I am building a new home in Sigar Land TX, near Houston. The foundation was poured on 7/8/00 and in about 3-4 days the slab has a crack running from.
7. Welcome to the leading informational site on the post-tensioning construction method, sponsored by the Post-Tensioning Institute (PTI)—a nonprofit organization for.

Imagine removing a ceramic tile floor from the surface of a slab. Depending on the extent of the damage, you may also have to put up the homeowners in a hotel during the repair. For these reasons, the average cost to repair cracks in a slab foundation ranges from $5,0. In general, it's more expensive to build a post- tension slab- on- grade foundation than a traditional one. The reason behind the extra expense is that the foundation must be more substantial to accommodate difficult soil conditions that have inconsistent or poor bearing capacities, such as expansive and organic soils. In the U. S., post- tension slabs are primarily constructed in the Southwest, where there are expansive (clay) soils, and in the Southeast, where there are organic (loam) soils. Expansive soil is a clay soil that shrinks when the water content lessens and swells when the water content increases.

As the soil shrinks and swells, it creates serious problems for the home that appear as cracks that can range from small cracks to cracks that run deep, reducing the slab's strength and durability. The most extensive damage to homes occurs in areas that have a semi- arid climate where periods of rainfall are followed by periods of no rainfall, such as in Arizona. In these areas, constructing a post- tension slab instead of a traditional slab is a good choice, because post- tensioning strengthens the foundation, allowing it to resist the effects of shrinking and swelling soil. Organic soil is a type of soil that contains a high percentage of organic matter. Organic matter, such as grass, roots and leaves, will decay under the slab, causing the foundation to settle and crack. In general, organic soil istoo compressible for a traditional slab- on- grade foundation; this type of soil can't be relied on for long- term support.

Post Tension slab cracks - Inter. NACHI Inspection Forum. With this year's prolonged drought many houses that never showed evidence of foundation movement before experienced cracks and movement. I saw numerous houses where the soil had shrunken so that I could fit my hand between the dirt and the side of the slab. With the expansive soils that we have around Houston, it's important to maintain even moisture levels all the way around the perimeter of the home and throughout the seasons of the year. Do you have an irrigation system around the perimeter of the house and do you use it to maintain consistent soil moisture levels? It is very common for houses in the Houston area to have hairline cracks.

The hairline cracks by themselves are generally not cause for concern unless you see significant gaps opening up, displacement across the crack or excessive spalling at the crack. Significant movement will typically cause several other signs of distress in the structure.

Construction of post-tensioned slabs on grade is very similar to. Suncoast Post-Tension.

A post-tension slab is a slab of concrete that has been pre-stressed to increase its strength. Using a post-tension slab is often.

If the structural engineer did not indicate that you had cause for immediate concern or recommend foundation repair, I would not worry too much about it. Did he give you any specific advice regarding foundation maintenance or repairs? I would suggest the following: 1) Keep the diagram that the engineer created with your foundation elevation readings. You can take fresh elevation readings in the future and compare them to the original baseline to determine if there has been subsequent movement, how much movement and what areas have moved; 2) Implement any recommendations that the engineer may have given you to help maintain foundation performance (e.

Maintain consistent moisture levels around your house and through the seasons (watch for signs of the soil pulling back from the foundation in dry seasons and water more when needed); 4) Monitor any potential signs of distress (i. If your engineer didn't tell you that you needed to worry, then don't sweat it. Houses are dynamic, they all move some throughout the seasons. Mitigate any detrimental conditions and keep an eye out for significant stress indicators (the house's, not yours).