What I'm Seeing Now


Without A Stamp How Do You Know It's FRT Plywood?

Without a stamp how do you know it's FRT plywood?

Fire Retardant Treated plywood is required as roof sheathing fire protection between abutting houses - duplex, condo, or townhouse.  It is commonly called "FRT plywood."

You can tell the brand and quality by viewing a stamp.  The stamp needs to be visible, by code.  Each plywood manufacturer has its own stamp.  One manufacturer's stamp is red, so it is hard to miss.

The fire-coded stamp must be present so it is visible from the attic space and can be viewed by the local jurisdictional authority to insure it is FRT and certify that FRT plywood has been used.  The Uniform Building Code says this:

A Fire-Retardant-Treated backboard will be designated with a fire-rated stamp “branded” or “stamped” along the edge or center of the plywood — “UL FR-S Plywood 1780 R-7003.”

I always look for the stamp.  When I can't see it I have no choice but to note it on the report.

The stamp has a lot of information as well.  The A-C   is the grade.  A  means it is a very smooth, and a good-grade veneer on the interior side.  C  is the grade for the exterior side.  An interior grade of C  or D  is an inferior plywood and costs less.  The "Exterior" means that 90% of the plywood has a glue that will not dissolve from outdoor humidity and can be used for roofing. 

Yes, there are different glues for different plys!  The stamp is on the interior side to demonstrate which side to put DOWN!!

The code requires the local jurisdictional authority to verify that a quality FRT plywood has been used.  And the only way to know that is to see the stamp.  Sometimes the edge has been colored, but that still does not give the information the stamp would provide.

In this new construction, not only did the plywood NOT have stamps visible anywhere, but it looked to be of different grades due to the different colors of the veneer.

I did not do a pre-drywall inspection or this would have come up then. That is the stage the county would have verified the FRT presence and signed off on it.

Did they sign off on the fact that no stamps, or colored edges, are visible?

At this final inspection I have no choice but to bring this fact up. 


Of course, my clients and the Realtor had no idea and had never heard anything like this before.  The "supervisor" is maybe 22 years old and I wonder if he has either.

My recommendation:  this is one case in which Big Brother is really looking out for us.  Fire codes happen because of information learned from fires.  FRT plywood and the fiberglass asphalt shingles on top provide great fire protection between units.  BUT THE STAMPS HAVE TO BE VERIFIED!




Jay Markanich Real Estate Inspections, LLC  

Based in Bristow, serving all of Northern Virginia.

Office (703) 330-6388   Cell (703) 585-7560


Comment balloon 9 commentsJay Markanich • June 13 2014 02:22AM


Yes, tis is ann important safety feature and glad you pointed it out.  It should have been caught earlier.

Posted by Debbie Gartner, The Flooring Girl & Blog Stylist -Dynamo Marketers (The Flooring Girl) about 5 years ago

Wow. This really  is great information.  I had no idea, naturally.  With all of the new construction in this area over the years it never dawned on me, either.  You can bet I'll be looking the next time I'm on a site.

Posted by Chris Griffith, Bonita Springs Listing Agent (Downing-Frye Realty, Bonita Springs, FL) about 5 years ago

Well regardless if they knew about it or not they do now.  Personally I did not know that thanks for the lesson

Posted by James Dray, Exceptional Agents, Outstanding Results (Fathom Realty) about 5 years ago

That's why I like to do a pre-drywall inspection Debbie.  They didn't think it "necessary."

They have been using FRT since the 80s Chris.  The first generation did not do well.  But all of the brands are good now.

They sure do James.  I wonder what will happen with this information now that the builder has it.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 5 years ago

This is a situation where agents who have been licensed and practicing since the early 1990s have an historical insight into a matter, specifically FRT. 

It's quite complicated and involves the past and present use of FRT.  Yes, it's still used.  However, not as before which was routine. 

If there is a question, it can be included in a Contract of Sale that the seller provide verifications.

Posted by Lenn Harley, Real Estate Broker - Virginia & Maryland (Lenn Harley, Homefinders.com, MD & VA Homes and Real Estate) about 5 years ago

Good morning Jay,

Thank you for the information; I will be asking the next condo inspector what is up there.

Make yourself a great day.

Posted by Raymond E. Camp, Licensed Real Estate Salesperson Greater Rochester (Howard Hanna Real Estate Services) about 5 years ago

This is the final walk through in new construction Lenn.  It's the same house as the high kitchen vent (Loudoun County).  Of course it's still used - FRT is required anytime there is a fire wall and the stamps need to be legible by code. 

Raymond - condo, townhouse or duplex!  Anywhere there is a firewall abutting two units.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 5 years ago

What an excellent discussion of FRT and the importance of finding the stamp indicating it is FRT. 

Posted by 1~Judi Barrett, BS Ed, Integrity Real Estate Services -IDABEL OK (Integrity Real Estate Services 118 SE AVE N, Idabel, OK 74745) about 5 years ago

Thanks Judi.  You have to be able to tell it's FRT!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 5 years ago

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