In an ideal world, designers and engineers would choose to build a particular structure on land that was mostly free from any obstruction or underlying problem that might affect rigidity. However, this is difficult to achieve in a densely developed area, where the land itself is valuable and commercial pressures abound. What kind of challenge can this present to an engineer or builder, especially when it comes to the risk of water infiltration?
Interrupting the Water Table
Even though the climate may be relatively arid, a large underground body of water may nevertheless exist close to the surface. This water may ebb and flow according to geological conditions, but it will always represent a threat to any form of man-made construction.
Developers may have to build on this low ground topography where drainage patterns are not conducive to the work in hand. They will need to pay close attention, therefore, to the way that they lay any concrete belowground to make sure that the project is successful and that they avoid any future problems.
When the foundations of a building interrupt a particular drainage pattern, the water pressure can build up in and around the concrete formation. As concrete is generally porous, the water will enter the structure and may introduce additional contaminants or chemicals at the same time.
Damage and Degradation
This infiltration can cause structural damage to the concrete itself and may cause the steel reinforcement to corrode. Chemical reactions can cause degradation, and this will eventually cause aboveground issues that they will need to address.
Freeze and Thaw
If the water infiltration is close to the surface and the area is prone to a sharp winter frost, then this can lead to a freeze and thaw process as well. Clearly, this will cause additional cracking and damage to the concrete unless there is some form of protective layer in place to keep the water at bay.
Positive and Negative Membranes
As you can see, it is essential to introduce a waterproof membrane when they initially lay the concrete. Some engineers choose to add two separate membranes on the outer layer of concrete (the positive side) and the negative side inbound. The positive membrane should keep water at bay and will help to avoid the buildup of hydrostatic pressure. Should the positive membrane fail at any particular point, the secondary layer of protection should help prevent any future problems.
Make sure that your new structure is protected. Ask your concrete contractor about their approach to waterproofing membranes.