Whenever I teach a class on fire door inspection, questions always come up about holes in fire doors and how to fill them.  I promised a class of 120 last fall at the Yankee Security Conference that I would write a blog post about it, but there was really no good solution, particularly for wood doors – until now.

Here’s what NFPA 80 says about filling holes in fire doors (2007 and 2010 editions): When holes are left in a door or frame due to changes or removal of hardware or plant-ons, the holes shall
be repaired by the following methods:
(1) Install steel fasteners that completely fill the holes
(2) Fill the screw or bolt holes with the same material as the door or frame

The sixty-four thousand dollar question is, “What is the ‘same material’ as a wood door?”  And on a hollow metal door, is covering the holes with a steel plate the same as filling the holes with the same material as the door?  A common fix that I’ve seen on hollow metal doors is to fill the holes with steel screws, grind off the screw heads, smooth it out with some automotive body filler (Bondo), and paint over it.  But what about wood doors?

I have a pal who is a fire marshal for a large government facility with multiple buildings.  One of the common issues he sees when inspecting their own fire doors, is the use of filler materials that are not listed for use on fire doors.  In his search for a solution to this problem, he contacted several listing agencies, manufacturers of various fillers, and even the Joint Commission.  While the listing agencies and manufacturers seemed open to the use of automotive body filler (Bondo) for filling small blemishes in hollow metal doors and frames, they confirmed that it was not acceptable for filling holes.  There was also concern about using materials which contain chemicals and in some cases carcinogens.  But given the lack of feasible options other than replacing the door, some AHJs may have accepted these fillers, or not realized that they had been used.

Finally – FINALLY! – a filler has been successfully tested for use on wood fire doors, and can be used to fill holes a maximum of 3/4″ in diameter on a wood door rated for up to 90 minutes.  Fire Door Caulk from Fire Door Solutions is listed by Intertek under the Warnock Hersey mark. It has been tested per the requirements of NFPA 252, UL10B, UL10C, and CAN S104. Fire Door Solutions also stocks a product for use on fire rated hollow metal doors – Fire Door Thru-Bolts. They are available in 1/4″ or 1/2″ diameter for doors 1 3/4″ to 2″ thick.

Check out the products offered by Fire Door Solutions here, and let me know what you think!  If you have any questions, just leave a comment and I will get you an answer.



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