Most types of firestop putty have ________ properties.

While some firestop products use water-based carriers or binders, 'water-based' describes a formulation method rather than the active fire-stopping mechanism of putty.

Cementitious firestop products are mortar-like compounds that harden and resist fire through their mineral composition, which is a separate product category from putty.

Intumescent materials expand significantly when exposed to heat or flame, which allows firestop putty to automatically seal cable and pipe penetrations during a fire event. This expansion fills gaps and voids created as combustible materials burn away, maintaining the fire rating of the wall or floor assembly. Intumescent expansion is the primary and defining fire-stopping mechanism in putty-style firestop products.

Silicone-based firestop products are typically flexible sealants or caulks used in different penetration types and do not share the expanding mechanism characteristic of putty.