Concrete Slab

In cases of rat entry through the ground, concrete may be the best option to install in an existing crawlspace.  There are some negative results to be aware of when choosing the concrete slab option in crawlspaces. Concrete is made with large quantities of water, and therefore shrinks as it dries.  This shrinkage results in cracking and separation from the foundation edges. The apparent seal by using concrete is immediately lost once the concrete is dry. Concrete being poured in an existing home will also create a high humidity situation for several weeks, and the home itself will become wet, possibly warping floors and creating a mold potential.  Good ventilation afterwards will be important steps to take to avoid this. Lastly, concrete that is pumped into a crawlspace is made with large quantities of fines, such as fly ash and portland cement. The basic darby float finish does not “tighten” the surface because installers do not complete the install with a “steel trowel” finish, and a high silica dust and scaling will occur at times.