Author Topic: fireblocking  (Read 2864 times)

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Offline mrFinpgh

  • Posts: 203
fireblocking
« on: April 28, 2017, 05:42 PM »
I will be having an inspector out next week, but wanted to see what the thinking was here.

I have a rowhouse with brick walls, so I'm putting 3/4" x 2" plywood furring strips along one wall to give myself something to screw cabinets to and perhaps allow the electrician to run wire along.     I'm also running 3/4" furring  horizontally across the old fireplace to drywall over that.   The fireplace itself is blocked w/ durock and capped at the chimney.

I'm also furring the short side of the fireplace and walling that up, so I can have a wall for a switchbox.

The furring on the wall for cabinets will end about 6" short of the ceiling.  The other furring will also be slightly off the floor and ceiling (maybe 3" each end). 

The existing ceiling is finished, and consists of drywall over plaster and lath.

In each of these cases, do I need to install perpendicular material of some kind to act as fireblocking?   If i don't, is the inspector more likely to give me a rough time? 

What about the exposed end of the cabinets, where I will cover up the gap to the wall with an end panel?

Thanks,
Adam





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Offline antss

  • Posts: 1032
Re: fireblocking
« Reply #1 on: April 28, 2017, 11:05 PM »
Fireblocking is require pretty much everywhere with wood framing.

I wouldn't want the electrician running wire anywhere near where you've placed blocking to attach cabinetry, let alone on it.

The plumber for that matter should be kept outa those areas too.

Maybe Brice can say definitively  for your area on the fireblocking.

Offline tjbnwi

  • Posts: 4926
  • Cedar Tucky Indiana
Re: fireblocking
« Reply #2 on: April 28, 2017, 11:29 PM »
Run the strips all the way to the ceiling, this prevents horizontal flame spread, the drywall ceiling acts as the vertical fire stop as long as the drywall is tight to the existing brick.

Tom
« Last Edit: April 29, 2017, 12:04 AM by tjbnwi »

Offline rizzoa13

  • Posts: 535
Re: fireblocking
« Reply #3 on: April 28, 2017, 11:36 PM »
You'll be drywalling over top of the furring strips and behind the cabinets correct? if so just make sure you tape at the ceiling.

If not I dont think itll be a problem either way as the residential codes for fireblocking are primarily to stop the spread of fire between floors. your finished ceiling acts as your firebreak between levels and i dont think theres precidence for any fireblocking codes to come into play.

Offline mrFinpgh

  • Posts: 203
Re: fireblocking
« Reply #4 on: April 29, 2017, 12:24 PM »
Hi all,

Thank you for the advice.  I'm fortunate to be able to go to a place like this and get advice from folks far more experienced with these things than I am.

As I understand it, the finished ceiling (which is 1 7/8" thick and definitely tight to the corners) suffices as a fireblock.  I'll run the furring up to the ceiling.

@rizzoa13 - I'll be drywalling over the furring where I'm covering up an unused fireplace.   The furring behind the cabinets is just to give myself something solid that I can make flat before attaching the cabinets.  It will be approximately 8' x 8' of cabinets.  I want to run LED tape behind the front of the shelves, so having a little space behind the cabinet should work to my advantage there as well.

Here is my mockup:

262578-0

I plan to build 8 2 door cabinets, and then the middle will be an open shelving unit.  I'm still debating on if it makes more sense to build two units + trim in place, or try to trim as a single unit and then fit it between the two outermost stacks.

Thanks,
Adam

Offline Brice Burrell

  • Posts: 7190
  • Remodeling Contractor
    • The Green and Dark Blue blog
Re: fireblocking
« Reply #5 on: April 29, 2017, 02:03 PM »
Adam, I believe you already got your answer.  To be clear, you are furring out in an already finished (or mostly finished) space, as in the space is fully drywalled/plastered, correct?  If so, you haven't disturbed existing fire protection, so no fire blocking is needed. 

If you have open framing that would allow fire to directly travel from one floor to the next, then you would have to use fire blocking.   
Check out my new blog, The Green and Dark Blue Blog.

Offline mrFinpgh

  • Posts: 203
Re: fireblocking
« Reply #6 on: April 30, 2017, 03:17 PM »
Thanks, Brice.

That's correct - the space is mostly finished already and completely plastered.

As a followup question, what do you guys do when the brick turns out to be too hard for drilling?

I've broken two Bosch hammer drill bits in the past hour trying to finish this up.   I suspect the fireplace face brick is some order of magnitude harder than the brick that I drill the other 70 holes in.

I usually read that people advise against drilling into the mortar.. but if there is another way to do this, I'm all ears.  I'm tired of drilling holes in brick.

-Adam

Offline Brice Burrell

  • Posts: 7190
  • Remodeling Contractor
    • The Green and Dark Blue blog
Re: fireblocking
« Reply #7 on: April 30, 2017, 04:56 PM »
Adam, I've run into some hard brick but nothing insurmountable.  Are you using a rotary hammer or a cordless drill with hammer drill feature?  The hammer drill on cordless drills is pretty weak.  It can be very slow going on harder brick so you could be overheating the tip.  The same thing can happen with a rotary hammer but you usually get a few holes along the way.

If you decide drilling the mortar is the only rout forward I'd use a sleeved anchor, not a masonry fastener like a Tapcon.       
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Offline antss

  • Posts: 1032
Re: fireblocking
« Reply #8 on: April 30, 2017, 05:39 PM »
Are you sure you're not hitting steel in those hard to drill places ?

Offline mrFinpgh

  • Posts: 203
Re: fireblocking
« Reply #9 on: April 30, 2017, 06:43 PM »
@Brice Burrell , I'm using a corded hammer drill.  Nothing fancy.  I've run into this before with my bathroom, where the plumber had to use an SDS to drill the concrete, because I spent hours on the floor without making more than about 1/4" of a hole.

@antss - I guess that's possible?  I don't see any evidence of steel, but I could easily imagine some kind of steel lintel hidden behind the brick. It seems unlikely, but I wouldn't dismiss it. If I drill into the mortar on the bricks above or below, it seems easy to penetrate.  The brick is drillable - I did get a few holes drilled along the way, but it went from taking about 1 or 2 minutes per hole to nearly 10 minutes.   

For what it's worth, I'm hanging about 50sq feet of drywall on this wall.   If I could get away with it, I'd use glue.

-Adam


Offline rizzoa13

  • Posts: 535
Re: fireblocking
« Reply #10 on: April 30, 2017, 08:26 PM »
So what're you using to hang the drywall? Is this the wall that's getting furring strips? If so I'd get enough tapcons into that drywall for it to stay in place and then use a Ramset to attach the furring strips through the drywall into the brick. Much quicker with a ramset.

Offline antss

  • Posts: 1032
Re: fireblocking
« Reply #11 on: April 30, 2017, 09:20 PM »
"did get a few holes drilled along the way, but it went from taking about 1 or 2 minutes per hole to nearly 10 minutes.  "

Then you're wearing out the bits due to excessive heating most likely.

What brand of bit are you using ?  You can also use a water bucket to cool the bit as you drill.  I'd also use a punch to break the surface of the brick and to make a guide for the bit.  A smaller pilot hole can help too.

  10 min. for a 1/4" diameter hole or less means you're not really drilling anything.  [eek]

Offline mrFinpgh

  • Posts: 203
Re: fireblocking
« Reply #12 on: May 02, 2017, 10:12 PM »
I see what you're saying about burning the bit. I've done that before trying to drill 100 year old concrete.

It seems odd to me that I could drill so many holes - or at least 48 - without issue.   And then with a fresh Bosch blue granite bit, find myself getting such slower progress.

At any rate, I'll probably just use plastic anchors in the mortar until I get above the face brick. 

@rizzoa13 - I'm a little confused by the sequence you outlined.   I'm putting the furring up over the brick, and then hanging the drywall on the furring.    I've never used a ramset, but they do look like a fast way to get it done.   

Thanks ,
Adam



Offline rizzoa13

  • Posts: 535
Re: fireblocking
« Reply #13 on: May 02, 2017, 11:02 PM »
Ahhh my apologies I thought you were putting furring strips over the drywall. A ramset could be used to attach the furring strips to the brick though and then the drywall screwed to it.

Full disclosure though a ramset could be frustrating in old brick, it's likely to chip out when you shootnit unless you've practice with what your doing. You'd want to shoot directly into the brick so you've got the most meat and least likelihood of chipping off the edge of the brick.

Offline mrFinpgh

  • Posts: 203
Re: fireblocking
« Reply #14 on: May 08, 2017, 06:12 PM »
A couple more bits bite the dust!

I suspect I may be putting too much pressure behind the drill, and the hammering is bending the bits.  I'm barely an inch into the mortar and it's like I've hit a brick wall, so to speak.

I was able to use a blue plastic anchor in a hole in the mortar joint.   I screwed a board to that and it holds well enough that you can bend the furring strip a few inches away from the wall with no pullout. Maybe if I stop breaking bits I'll be able to drill enough holes

That said - any other good ways to attach 1/2" drywall to a brick wall?   I'd be perfectly happy skipping any more furring strips.

-Adam

Offline rizzoa13

  • Posts: 535
Re: fireblocking
« Reply #15 on: May 08, 2017, 06:33 PM »
Hi Adam. If your having trouble with the drill for some reason you could use push the drywall up against the wall, take your furring strips and use a ramset to attach the furring strips through the drywall. It'll sandwich the drywall in.

Offline antss

  • Posts: 1032
Re: fireblocking
« Reply #16 on: May 08, 2017, 06:55 PM »
You'd have to give up another 3/4" , but you could frame up a metal stud wall in about an hour.

It'd give you some insulating and sound abatement qualities in the bargain though.