Unique Core Bore Seal

Core Bore Firestop System


Unique Core Bore Seal bottom view



The UNIQUE Core Bore Firestop System is a revolutionary way to cover, fire stop, water and smoke seal abandoned (empty) core holes in fire-rated concrete slabs and walls. You may walk on it after installation!  The nut holds the system together and is not removed.  NO TOOLS REQUIRED.  Drop it and forget it so there is no need to access the floor below.  The retention prongs are shown (right side) in the bottom view. (May still be removed by accessing the floor below to remove the lock nut)


Now in sizes for 1.5 – 2.0 – 2.5 – 3.0 – 3.5 – 4.0 – 4.5 – 5.0 – 5.5 inch diameter core bore holes.  From 3 to 12 inch’s thick.

The STOP sign is the TOP View and the other pic the BOTTOM View.  The top plate gets a bead of caulk underneath.  As you drop the system in the core, the bottom plate is sized to the core. Position the top plate, center it, step on it and the system is sealed from FIRE – SMOKE – WATER.  The top plate is about .075 thick and can be covered by carpet.  The muffin is made by STI.  System may be easily removed and does not require access to the floor below.

UL Classified. Made in the USA.


New Design! New manufacturing details have been added to our Core Bore Firestop System so it is now removable when your sealed core needs to be re-used .

New Sizes! Now available in 1.5″, 2.0″, 2.5″, 3.0″, 3.5″, 4.0″, 4.5″, 5.0″, and 5.5″ to better fit your core hole’s diameter. These system sizes are based on the core hole’s diameter. For questions about choosing the correct size, installation or anything else, call our friendly expert Customer Service Support at 251-960-5018.

Use our UNIQUE Core Bore Firestop System to cover and firestop empty core holes in concrete slabs or walls during construction and post-construction. These core holes are often abandoned when firestop sleeves or conduits in a concrete firewall or fire-rated barrier are removed. Empty holes can be dangerous because in case of a fire, the firewall will fail to protect the occupants as expected.

Our Core Bore Firestop System saves installation time and money while meeting all building codes. It is made of high-grade plate steel and a firestop muffin (plug). It comes with everything needed to install it except the firestop caulk. The heavy-duty Core Bore Seal is inserted into the hole and the prongs grab the inside of the core hole to fasten the system in place. A bead of caulk under the top plate will smoke seal the Core Bore to the slab or wall. Our Core Bore Firestop System provides 100% firestop and smoke protection.

The entire system can easily be removed and is completely reusable if the core hole needs to be reactivated.


Select proper size CBS by measuring the Core to be firestoped and sealed.  CBS’s come in 1/2 inch increments.

Clean the top edge of the core bore with a clean damp cloth to remove all dirt and debris so a good seal can be made.

Apply a 3/8 to 1/2 inch bead of intumescent fire stop caulk to the floor/wall where the CBS will make contact.

Be sure the prongs are spread evenly and place the CBS carefully in the core bore.  Step on it.  Wipe away excess caulk.  ALL DONE!

Order Unique Firestop Caulk here. It’s the perfect general-purpose firestopping sealant for all your firestop installation needs.

UL Classified with STI intumescent plugs.


Access the SDS for the fire-rated plug (muffin) here:

Certificate of Compliance

Access the Certificate of Compliance for this product:

Certificate of Conformance

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Product Data Sheet

Access the Product Data Sheet for the Intumescent Plug:

Engineering Judgement