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Concrete & Masonryaka: lean concreteaka: blinding slabaka: sacrificial slabaka: rat slab

Mud Slab

In Plain English

A thin, rough concrete layer poured under the main slab just to provide a clean, stable work surface.

Definition

A thin, plain (unreinforced) concrete slab, typically 2 to 4 inches thick, placed on prepared subgrade to provide a clean, stable working surface for waterproofing, formwork, or construction activity. Mud slabs are not structural and do not bear building loads directly. They serve as a base for vapor barriers, waterproofing membranes, and a working platform for crews.

Example

A 3-inch mud slab was poured over the prepared subgrade to protect the waterproofing membrane during structural slab construction.

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