At the risk of y’all getting sick of my double-letter abbreviations, I’m going to add QQ to WW and FF.  People always call me and say “I have a quick question…” (QQ).  For some reason everyone thinks I’m busy and they don’t want to take up a lot of my time.  I AM busy, but this is my job – supporting anyone who has questions about codes related to door openings, doing research to help interpret the codes, and working to change the codes when they need to be clarified.  Here’s a “quick question” that I received recently:

When I’m installing a fire-rated frame into an existing opening using existing wall anchors, how much space can I have around the frame, and what is permissible to use to seal that gap?

That’s a really interesting question, because Annex A of NFPA 80 includes this diagram for a frame with existing wall anchors:

Anyone who has installed a frame in an existing opening knows that is virtually impossible to install the frame with zero tolerance between the frame and the rough opening.  This happens on occasion…a conflict between a code or standard and real-world applications or what is stated in the listing.

I checked with one of our engineers at Steelcraft, and he sent me the portion of our UL listing that describes this application.  This may not be the same for every manufacturer so it’s worth double-checking if your frames are not manufactured by Steelcraft, but my guess is that the requirements are pretty consistent.

Our listing details for existing masonry walls (up to and including a 3-hour rating) allow the rough opening to be 1/4-inch more than the height of the frame, and 1/2-inch more than the width of the frame.  Shims made of 16-gage or 12-gage galvanized steel must be installed above each of the anchor points.  The required size of the shim is 2 inches high x 1/8-inch less than the frame jamb depth.  For sealing the gaps around the frame, our listing allows pure silicone caulk, intumescent caulk, or grout.  Frames are not required to be fully-grouted.

Do you have a QQ (quick question) – or even a question that is not a quick one?  Feel free to email me if you can’t find the answer on

Graphic:  NFPA 80-2016.  NFPA standards and handbooks are available at

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