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I just started framing my place and have placed fire blocks in the between the studs at 48 inches high all long exterior walls, but am wondering do i have to do the same for interior walls?
 

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I just started framing my place and have placed fire blocks in the between the studs at 48 inches high all long exterior walls, but am wondering do i have to do the same for interior walls?
Yes and no.

If the hollow interior bays between each stud of your interior wall, in any way, lead ANYWHERE but just straight up to the top plate, with solid drywall on both sides, (or even without D/W on both sides) they will likely require fire blocking. The point is to eliminate any chance of the inside of that wall becoming, in effect, a chimney that might lead or direct flames into another part of the house. This includes side holes drilled in the studs for wires or pipes to run horizontally or vertically... or diagonally.

For instance, if you have soffits for your kitchen cabinets, obviously the drywall does not separate the backsides of those soffits from the wall below (as far as being a fire passage). Nor does it separate the soffits from the ceiling.

It's a common sense thing. Just pretend you are a flame in a wall, and go looking for ways you could possibly get through to any other part of the house. Do this for every stud bay of every wall. Did you read EVERY STUD BAY? Yes, codes do allow some lateral travel, but it's your house, your family. Play it safe, and block each and every bay. This is not one of those places to stop short of doing all you can do just because you're legal. Fire kills.

Anything that leads from one floor to another requires fire blocking.

Stairwells are bad for this. Real tricky sometimes. Enclosed fireplace surrounds have a lot of passages all the way up to the roof. They gotta be blocked at each obvious level. Dropped ceilings anywhere usually create a hazard.

As you are doing all this keep trying to envision the walls and ceilings drywalled. Where will they NOT be covered? Can flames pass through anywhere around there?

The vertical passages, most people understand, but there are all sorts of lateral passages that the average framer overlooks.

Think like a flame, and strain to find a way out of that wall you're looking at. Remember, this includes the small holes drilled for wires and pipes. They have to be filled with fireproof foam. Flames can make themselves VERY skinny.
 

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I wasn't aware of any need to fire block exterior walls at 4' ?
Even ballon framing you would fireblock at the floor/ceiling change
 

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Although interior walls must be fireblocked, there is no 4' requirement in the IRC code. They must be fireblocked at the platelines and any spaces that exceed 10' heights.

4' blocks are typically for blocking edges of exterior sheathing laid horizontally, and aren't intended to serve as fireblocks.

Check out my fireblocking tutorial in the "how to" subforum.
 

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Its my personal opinion that bracing (fireblock?) at the 4' level is a good idea as it will keep the studs from twisting and popping the drywall screws.

However, your electrician will hate you for doing this!
 

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Its my personal opinion that bracing (fireblock?) at the 4' level is a good idea as it will keep the studs from twisting and popping the drywall screws.

However, your electrician will hate you for doing this!
That's one benefit, but the greater benefit of horizontal blocking is the additional shear strength the wall gets from having the horizontal edges of the exterior sheathing blocked and nailed off. It increases the wall's racking resistance significantly.
 
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