These Houston foundation repair customers are willing to refer new customers to Dawson at anytime. They we very satisfied with the repair process which was longer than most because of need to fill-in voids under the interior portion of the house. If soil is not compacted properly prior to the pouring of the concrete slab foundation then over time it may compact itself via changes in moisture content. Or there may have been a leak from a waste water line. This will require under slab plumbing repair. One of the last steps is to fill any void that remains under the foundation. Typically a slurry of mud and concrete is pumped into the void to fill every vacant crevice. This slurry will harden and then provide the extra support needed between the soil and the slab foundation. Call us TODAY. Read more of our testimonials. Quality Houston Foundation Repair – Testimonial #250.