The SpecSeal SSP4S is a professional-grade firestop putty pad designed to protect electrical boxes in fire-rated gypsum wall assemblies. Each pad measures 7.25 inches square and 3/16 inch thick, nearly twice the thickness of most standard putty pads on the market. This added mass delivers superior fire protection and acoustic performance compared to thinner alternatives.
How It Works
The pad uses a two-stage intumescent technology. Under normal conditions, it remains soft and pliable, forming an airtight seal around outlet boxes, switch boxes, and other membrane penetrations. When exposed to fire, the intumescent compounds activate at 230°F and expand to more than five times their original volume. This expansion seals the opening and blocks the passage of flames, smoke, and hot gases through the electrical box penetration.
Unlike calcium-based intumescent products, the SSP4S contains no water-soluble expansion ingredients. This means the active compounds won’t wash out if exposed to moisture during construction, and the pad maintains its protective properties over the long term.
What Makes It Different
The non-hardening formula sets SpecSeal apart from sealants and caulks that cure rigid. The putty stays pliable indefinitely, so you can reposition it during installation, make adjustments after inspection, or remove and reuse it during renovations. For contractors, this eliminates the rework headaches that come with hardened firestop materials.
The SSP4S also pulls double duty as an acoustic seal. With an STC rating of 62 in tested constructions, it outperforms many competing putty pads (typically rated STC 50-55) for sound isolation. This makes it a practical choice when fire protection and soundproofing are both specified on the same project.
