FOUNDATION-SLAB SEPARATION NOTED

FOUNDATION-SLAB SEPARATION NOTED
There are many methods of pouring slabs and footings. Most are monolithic pours, or "one piece" pours. Monolithic pours are somewhat stronger than pours that have "cold joints" in that the adhesive strength of the cement and aggregate mixture at the juncture of the slab and footing is maintained. A common method of pouring footings and slabs is to pour the footing (leaving 3 to 4 inches off the top to allow for the slab) then the next day or so, pour the slab. This causes a cold joint between the footing and the slab which appears as a horizontal line around the building's foundation. If the soil below the slab is expansive and moisture enters the area below the slab, or if the earth around the perimeter of the foundation is allowed to dry excessively, it is possible for the slab to lift slightly off the footing. Ordinarily reinforcing bars are installed and the lift is minimal. However, in some older buildings "rebar" was not required or installed (or not installed properly) and lift of the slab may be magnified. Another method of installing slabs is to pour the footing to full height and in a day or so, pour the slab within the footing, using the footing as a "form." Many garage slabs are poured this way. If lift occurs with this slab system you may never notice it because the crack is usually under the frame or flooring and not visible. One minor problem with this type pour is that the crack can allow insects to enter the building under the flooring. Nothing can be done about this problem other than cosmetic cover-up and actions to help prevent further lift. It is recommended that you seal the crack with plaster patch, stucco color coat, silicone caulk, or similar products, to prevent water entering the crack and/or insects from entering and causing further lift or other discomforts. If you need further assistance you should contact a Concrete Contractor. Contact NJ home inspectors for more information and assistance.

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