Pre-Constructed Vs. Build-Your-Own Post-Tensioned Concrete Slabs

Post-tensioned concrete is stronger and more durable than standard concrete slabs. When you are looking at building something that will need to support several tons of automobile or the weight of a skyscraper, you have to start with a foundation of post-tensioned concrete. If this is a whole new dimension of construction methods for you, there are two ways to go about this; pre-constructed post-tension slabs, and build-your-own post-tensioned slabs.


The pre-constructed kind of post-tensioned concrete slabs are created in a factory. Numerous cylindrical chambers are made, either by a drill or by concrete mold, within a slab. Then the rebar or other metal cabling is threaded through the slabs. The slabs are sold and ready to install, via a post tension supplier. However, these pre-constructed slabs may be more difficult to manage if you need to post-tension a very large foundation/area.


Most contractors prefer to build their own post tension concrete slabs. This method gives you greater control over the size of the slab you need to pour, as well as the amount of post tension cable and/or rebar you use. All of your much-needed supplies may be obtained through a post tension supplier. 

In this case, you and your crew will spend several days laying down a grid of cable, rebar, and posts to create tension in the surface of the concrete. Then you will pour and construct the concrete slab over and through your grid. As it begins to dry, you will tighten the grid, creating tension in the concrete.

Once the concrete has almost fully dried and cured, you release the tension. The posts may remain in situ, or they can be removed, depending on the construction that will overlay the slab. This whole process takes much longer than the pre-constructed slabs, but it has a much better chance of lasting longer and not cracking under pressure.

Cost vs. Experience

Obviously, making your own post tension concrete is a little more costly. However, when you consider your level of experience with this technique, it may be better to purchase the less expensive pre-constructed slabs, which will be easier for you to install. It also depends upon the expected amount of weight the slab is supposed to support. Thankfully, the pre-constructed slabs are sold in varying thicknesses and cable strengths. A structural engineer can calculate the right thickness of slabs for the structure or objects that will eventually sit on top of the slab(s).

For more information, contact a company like Advanced Post-Tension, LLC.