Fire-Rated Garage Door Issues
Putting a pretty face on a fire-rated door is not as simple as it sounds. September 23, 2008
Question
We have been contracted to build all of the interior passage doors for a large house. We don't build doors on a regular basis (mostly cabinets), and the contractor wants us to build the door from the house to the garage. I know from my GC days that this must be a fire rated door, so my question to you all is; how does this door need to be constructed to pass a 20 minute fire rating? All of the interior doors will be 1 3/8" red alder frames with 1/2" alder veneer MDF panels. I would like to make the garage door look like all the others, but I am at a loss as to how. Any help would be greatly appreciated!
Forum Responses
(Architectural Woodworking Forum)
From contributor J:
It would probably be less expensive for you to buy it. I don't know where you are located but in East Texas, 20 minutes won't cut it. The door must be steel and must be rated for two hours. The jambs must be steel also. The trick is to buy the fire rated door and then make your interior doors to match if they must.
From contributor T:
To the best of my knowledge the door must carry a U.L. label. Unless you are a U.L. certified shop you can't make or alter a fire door. I agree with the previous post of buying it.
From contributor R:
I am doing a house and they bought a fire rated slab door and added 3/4 alder to match the inside door designs. This made for a deeper door, but it matches and is easier for you. Just make sure you use four hinges on it.
From contributor J:
I agree with Contributor T's response. I forgot to mention the UL requirement in my last post. It stated that I also need to make sure to buy the proper fire door for the application. Some fire doors have to be hung during the framing portion. Some can be retrofitted after the rock is in. Speaking of rock, we hung one last week where the inspector required two layers of 5/8" rock on both sides of the wall that held the fire-rated door. The jamb and threshold had to be special ordered because of the added thickness. The threshold was metal clip on and had to be added to the jamb before the door was set - what a mess. It took us one day to hand 50 doors in the house and another two days to hang the fire door.
From the original questioner:
Thanks for the responses. Your comments confirmed my thoughts that it would be easier to buy it. I hadn't thought of the UL certification. Thanks again.
From contributor T:
That fire inspector mentioning the 5/8" sheetrock is right. A 20-minute rated door must be installed in a 1-hour firewall. That's where the thicker sheetrock comes into play. And be careful. Adding plant-ons or other veneer might void the fire rating. Adding a fourth hinge or altering the hardware machining in any way will void the label.
From contributor B:
Contributor T is correct. With a labeled flush door you are only allowed a small % of the surface area you can cover with an appliqué before you void the label. I have seen some inspectors that notice the label and just keep moving, not even paying attention to the fact someone had affixed 3/4" of flammable material to one side of the leaf. Also note that if you do add a stick frame appliqué you cannot puncture the surface of the leaf to attach it.
Another item to look into is the jamb. Some areas allow 4/4 solid lumber to pass for a 20 minute opening while others will require the jamb to carry a label as well. Expect to pay hundreds of dollars for a labeled wood jamb. Make sure all the hardware you use on the door is also UL or WH labeled.
From contributor R:
Here in the LA area, if you add a layer on the house side of the door, you will not have a problem with the inspectors. The fire ratings are for the garage side of the door.
From contributor B:
In some areas it may not be a code violation to apply a full face appliqué but the manufacturer of the flush door will say that the label is no longer valid if that is done. Hence the liability would transfer to you for modifying the door.
