When you are getting the slab poured for your new home, the contractor may suggest that you use post-tensioning for your concrete.
Post-tensioning is a method of strengthening and reinforcing concrete. It puts the concrete under stress before the stress loads and load-bearing members are placed on the slab.
Post-tensioning is also a form of pre-stressing the concrete. It's done by placing various cables, called tensioning tendons, in plastic ducts in the forms for the concrete before it's poured. When the concrete is poured and cured, the cables are pulled taught and tension is placed on them. There are several benefits to post-tensioning.
Concrete will crack when it is put under stress. Post-tensioning will help to keep the concrete from cracking. While it will keep most cracks from happening, post-tensioned concrete will still crack on occasion. However, the cracks won't split open, since the cables will keep all the pieces pulled together tightly. Because the concrete is post-tensioned and cracks are kept firmly together, the need for joints is reduced.
Creating Thinner Slabs
Pre-tensioning concrete also allows your contractor to pour a thinner slab. If the concrete didn't go through the post-tensioning process, the slab would have to be thicker so that it could safely hold all the stress that your house is going to put on it. Since the post-tensioning cables help to reinforce the concrete and the process already puts the concrete under stress, the slab doesn't have to be as thick to support the same load.
Adding Support for Soft Soil
Soft soil can cause concrete to have cracks in it. That's because it can't give it as much support as firmer or less expansive soil would. Pouring concrete on soft soil, letting it cure, and then putting a load on top of it can be a recipe for cracks in your foundation or slab settling, which can cause damage to your house. After all, soft soil generally won't settle all at the same time. The post-tensioning cables set up the concrete so that the concrete more or less supports itself, even if the soil under it isn't ideal.
If you are getting ready to build your house and your contractor is talking about post-tensioning the concrete, you should definitely think about doing it. There are a lot of good reasons as to why you should do it, including the fact that it will save you money on repairs. Turn to companies like Advanced Post-Tension, LLC for more information.