Firestops

  • Thread starter Thread starter Michael Jones
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Michael Jones

Michael Jones

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OK, so I had Electrical, Mechanical, and Framing reinspected.

The Electrical and Mechanical passed!!!

Now, to get the framing signed off, I have to install firestops between all the adjacent interior walls.
What this means, specifically, is at the top of 2 adjacent walls, (like between the CR and the Drum Room) I have to put up a nailer, and then fit in some 5/8" drywall in there. Supposedly, this keeps fire from entering the "attic" should it start between the walls.

This will "link" the 2 rooms. :(

I guess I have to do it, just to get it signed off. I suppose I could go back and cut a slit down the middle of it, after its signed off.
Seems like a lot of trouble. :mad:
 
Here's a pic:

Imagine fitting a piece of sheetrock, at the top of the wall, like between the blue wall, and the green wall, and the brown wall.

Its a tight, confined space to work in, but it can be done. I'm not worried about physicalyl constructing it, I just don't want to link the rooms together like that.

Any alternative ideas?
 

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Maybe if you explain the detrimental effect that solid blocking would have on your design he might accept an alternative to solid blocking- like maybe stuffing the cavity with mineral wool blankets- not-so-solid blocking- Prob. not- but its worth askin. It'll accomplish the same thing and the spirit of the code is left in tact!
 
Rockwool is not fire rated to one hour. 5/8" drywall is.
I don't want to circumvent the code, and cut a slit through the drywall, so I was hoping there's an alternative.

But when its all said and done, I'll do what I think is necessary to maintain isolation.
 
Why on earth is the inspector dinging you for this? I could understand it in a duplex or fourplex, and certainly in an apartment building; where you don't want a fire to start in one end of a building and travel down to the other end through the attic.

I've never even seen this in a house. The only firewall requirements I'm aware of are between a garage and living quarters.

I've also seen draftstops built into large commercial buildings, and certainly firewalls between discrete shops in a multi-tenant commercial building.

Does he think your lava lamps have real lava in them or what???

I don't see any way that's gonna allow you to get away from coupling at least one set of walls to the roof trusses. Does it necessarily have to couple ALL of the walls in order to satify the inspector?

Maybe there's something that will allow you to drywall from the top down to NEAR the top plate of the walls, and fill in the gap with a 1 hour fire-resistant material that is flexible, providing at least some de-coupling while complying with the inspector's wishes.

Personally, I don't get what he's concerned about. It's a free-standing building. Is there only one exit accessable from your control and drum room???
 
C7- Around here, even in combustable constructiuon, fire blocking is required in all verticall spaces at floors / ceilings. But around here that blocking has to be 2X nominal lumber. Im talkin commercial though- not residential(I dont really do any residential anymore). Michael- is youre building a commercial structure (Im guessin not) We also use a slightly different model building code.

What if you lay gyp board over the opening but instead of screwing it down- you lay a FAT ASS bead of fire caulk across the top plates and put the gyp on that. Im not real sure how you've frammed this so that may or may not work- but just a thouhgt. It'll still couple but not as bad as screwin it down tight. Im not real sure how flexible the fire caulk is when it drys. Is fire safing material different than mineral wool? ( Im thinkin the stuff they stuff between the ridges of metal deck when a wall running perp to the ridges terminates at the underside of the deck)

[shruggs] i dunno
 
Michael, this is so wierd. Last week I posted a question on Johns site asking this very question.

After talking to an inspector here, he informed me that in a local commercial building with timber construction, there is no way to get around fireblocks in an exterior wall. And fireblocks are NO GOOD without being sandwiched between shiething. Which essentially means....there is NO WAY to use the existing exterior wall as part of a TWO leaf/TWO frame one airspace assembly, as the code reads the firewall must be fireblocked between sheathing on both faces of ONE frame. That means to comply here, a two leaf system must be built in ADDITION to the exterior wall, which in effect, means a 3 frame, three(4?) leaf system After asking, John said he got around it at one studio by lining the interior of the exterior wall with fireblock sheetrock, which he said, became the third leaf, but was ok by way of "leaks" in the battens on the exterior. Which makes sense, as thats how the pressure disipates I guess, However, this did nothing for me, as this did NOT comply with my local codes:rolleyes: NO ONE else even answered my question whether anyone else had come up against this conundrum while building a studio. That seems wierd to me, as ALL commercial studios must comply, at least I would think. Hmmmmmm, makes me wonder....(I wonder if they did what you are suggesting......hmmmmm:D ) But actually, your case is INTERIOR walls. But, IF a two leaf system IS the answer like everybody says, well damit, someone MUST have run into this SOMEWHERE:mad: Its as if this is some sort of a NO NO maybe?;) No one wants to discuss it maybe:rolleyes: ;) And no one wants to.....oh oh......wait, I don't think.....er ahem.........shhhhhhhh!:D sorry....hehehehehe!

(good luck Michael) hey, watch out for insurance issues :eek:
fitZ:)
 
Here in New Jersey I was required to place only Rock Wool for a firestop. I build my little studio room in the basement. I did not go the double wall route. We put the metal studs about 9 inches from the basement wall. The rockwool went in every joist leading upstairs. And trust me, the inspector we have is a royal pain in the butt. At a friends house the inspector once measured the studs to be sure they were 16 on center. But, every state has its codes. Good luck with this one.
 
Michael Jones said:
Here's a pic:

Imagine fitting a piece of sheetrock, at the top of the wall, like between the blue wall, and the green wall, and the brown wall.

Its a tight, confined space to work in, but it can be done. I'm not worried about physicalyl constructing it, I just don't want to link the rooms together like that.

Any alternative ideas?
Click to expand...

If you have the studs fastened to the floor/concrete then you have already linked the rooms. If your worried about the drywall transmitting in plane with the drywall its not going to be as bad because the limited thickness only allows a small vibration path, fractions of a db verse 5 or 6 db. If your really concerned you can use grommets in the dry wall so that there is a slip joint and you can purchase fire retardent flexible eurethane to make bulb seals. I had to design a smoke and fire barrier that also attenuated 73 db on an airplane. I'm pretty sure the FAA is more stringent on fire in the sky. If you could find a dealer that sells rolls of the flexible eurethane you could drap it between the walls and still meet code.

SoMm
 
C7 - I don't know why the inspector wants this. Apparently its a code requirement, but its a new one on me too.
I've seen firestops before, but inside a wall? Only if the wall is 12' high or more, or its a 2-story house.
Typically, firestops between rooms are done in apartments, and usually in the attic, across the trusses. During the planning and review portion of this project, I had an ingress/egress assesment done by the fire department. As long as there's 2 ways out, they were fine with it.

SoMm - The walls are attached to the floor, but there's a sheet of 1/4" neoprene under the bottom; which... flattened out to near nothing.

The Drum, Vocal, and Live room walls go all the way up to the trusses. But again, there's a cushion in there.

The CR is completely isolated from the rest of the structure. This firestop would connect it to the other rooms.

Right now, as it stands, I can put my ear against the CR framing, and have someone tap on the DR wall, and not hear anything as far as sound transference.
Attach a single 2x4 across the two walls, and you can definately hear the sound through the CR wall.

I guess I could run some neoprene along the length of the nailer, but.... man, what a pain in the nalgitas!
 
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OK, I just called my inspector. (He's really not a bad guy, and he's willing to help out with alternatives.)

Rockwool, as a firestop, does NOT meet the Local Amendments to the UBC.

But what I can do, is cut a slit down the middle of the drywall, and caulk it with a fire rated caulk. He even told me what kind to get, and where to get it.

So: 5/8" drywall with a 1/4" bead of fire rated caulk between them it is!

Here's more behind the rationale:
http://www.firestop.org/curtainwall.htm
 
So he will allow you to essentially use two pieces of drywall with a bead of firestop between them to fill the gap? One piece extending from the top plate of each wall toward the center of the void, stopping just shy of the center to allow a gap for firestop goop?
 
c7sus said:
So he will allow you to essentially use two pieces of drywall with a bead of firestop between them to fill the gap? One piece extending from the top plate of each wall toward the center of the void, stopping just shy of the center to allow a gap for firestop goop?
Click to expand...
Yes.
I'll put it up there as a single piece, and cut through it with a recipricating saw, then fill the gap with goop.
 
c7sus said:
I guess that seems simple enough if he'll buy it.
Click to expand...
Yeah. Well, thats his idea. I just feel like I'm jumping through hoops right now.
 
"I'll put it up there as a single piece, and cut through it with a recipricating saw, then fill the gap with goop." =-

Michael, you might want to use something that will make a wider kerf than a recip saw - if you have ANY sway in your walls you could negate your isolation. Plus, the narrow kerf of a recip saw wouldn't give you a wide enough space to get caulking to reliably penetrate well enough to make a full bead.

OTOH, if you cut a wide kerf for a full bead of fire caulk, it will be a MAJOR mess to clean up - you might find it easier to do separate pieces and use 3/16" shims between strips of drywall when fastening the second parallel piece... Steve
 
I was gonna make 2 cuts to get a wide enough gap.

Trying to do 2 pieces, on angled walls, with limited work space, and a 1/4" gap... well, I'm not buidling a watch.
 
"Trying to do 2 pieces, on angled walls, with limited work space, and a 1/4" gap... well, I'm not buidling a watch"

True, and I'm not trying to make it harder for you - that's a lot of mess to clean up, even a thin cut makes everything white for 10 feet.

How about cutting the two pieces you need, then taping 1/4" spacers to the edge of one every couple feet, fastening the OTHER piece in place, then pulling the spacers and caulking?

Or, if you REALLY like messes, mount a dado blade in your circular saw and make one cut... :=)
 
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