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-   -   Fireblock and Drop Ceiling (http://www.diychatroom.com/f19/fireblock-drop-ceiling-167961/)

325_man 01-01-2013 07:08 PM

Fireblock and Drop Ceiling
 
I have been reading about fireblocking in the basement in this forum. However, I think I am going to go with drop-ceiling for easy access and I have not seen the topic discussed before.

Is a different way of fireblocking if I want to go with drop-ceiling?

Thanks,
Nick

325_man 01-02-2013 08:08 PM

anyone?

TheCamper 01-02-2013 10:01 PM

Fireblocking the top of the walls would be the same. You need to prevent the movement of a fire from vertical to horizontal. I am not sure where you are looking to fireblock in the ceiling. How large an area is the finished basement and is the use a one-family dwelling? Are you talking about a fire rated separation between floor levels as needed to separate dwelling units?

325_man 01-03-2013 08:07 AM

Quote:

Originally Posted by TheCamper
How large an area is the finished basement and is the use a one-family dwelling? Are you talking about a fire rated separation between floor levels as needed to separate dwelling units?

The basement is about 1500 sq-ft.
No, I'm considering the drop-ceiling for quick access and need to know if i have to do anything extra for fireblocking.

Beepster 01-03-2013 11:11 AM

As Camper said, and as I understand fireblocking put most simply, it is to prevent fire from rising up a vertical wall and getting into a horizontal space.

Will the drop ceiling tiles be below the top plate of the walls? If so, I can not say for sure whether the walls will need to be fireblocked at or slightly below the height of the ceiling tiles. Either wait for an expert to pipe in or call your local building inspector and ask. Ultimately they are the ones that pass or fail (if under permit).

B

325_man 01-03-2013 12:43 PM

Quote:

Originally Posted by Beepster
As Camper said, and as I understand fireblocking put most simply, it is to prevent fire from rising up a vertical wall and getting into a horizontal space.

Will the drop ceiling tiles be below the top plate of the walls? If so, I can not say for sure whether the walls will need to be fireblocked at or slightly below the height of the ceiling tiles. Either wait for an expert to pipe in or call your local building inspector and ask. Ultimately they are the ones that pass or fail (if under permit).

B

I have never done drop-ceiling, but in theory it should be below the top plate of the wall. And, since the wall is fireblockes, my logical mind says that there is nothing more need to be done.

I'm hoping for an expert to pipe in.

leungw 01-03-2013 01:18 PM

Hello. I think most experts would ask you to talk to your town's inspectors, since different towns would have different requirements.

I put up suspended ceiling in my basement also and there's nothing different than drywall in terms of fireblocking. Below is what my inspector wanted to see at my fire inspection regarding fireblocking:
  • fireblock at the top of perimeter walls, and at every 10ft horizontally.
  • fireblock all soffits.
  • fireblock spaces between joists around utility room.
  • bottom of stairs must be drywalled
  • drywall or fiberglass must be used directly on all xps insulation.

325_man 01-03-2013 02:16 PM

Quote:

Originally Posted by leungw
[*]drywall or fiberglass must be used directly on all xps insulation.

Hi, can u please clarify the last bullet? If there is any picture, it would be helpful.

Thanks!

leungw 01-03-2013 02:53 PM

Quote:

Originally Posted by 325_man (Post 1085398)
Hi, can u please clarify the last bullet? If there is any picture, it would be helpful.

I first replaced the fiberglass in all the joist spaces with XPS. Next I cut drywalls into 10" x 48" strips and secured them on the joists around the perimeter, right against the sill above the concrete walls. I then put 2" XPS against the concrete walls and framed right in front of the XPS. I was going to leave the stud spaces empty and put drywall up. The inspector said I needed to cover the XPS with fiberglass in the joist spaces and stud spaces, to slow down the XPS from burning in case of a fire above the ceiling, or an electrical fire in the stud spaces. What he said made sense, even though no one else seemed to have to do it. In my case it was really down to getting all the XPS out, or putting fiberglass batts everywhere. I chose the fiberglass.

325_man 01-03-2013 06:53 PM

Quote:

Originally Posted by leungw (Post 1085424)
I first replaced the fiberglass in all the joist spaces with XPS. Next I cut drywalls into 10" x 48" strips and secured them on the joists around the perimeter, right against the sill above the concrete walls. I then put 2" XPS against the concrete walls and framed right in front of the XPS. I was going to leave the stud spaces empty and put drywall up. The inspector said I needed to cover the XPS with fiberglass in the joist spaces and stud spaces, to slow down the XPS from burning in case of a fire above the ceiling, or an electrical fire in the stud spaces. What he said made sense, even though no one else seemed to have to do it. In my case it was really down to getting all the XPS out, or putting fiberglass batts everywhere. I chose the fiberglass.

Thanks, leungw! That is how I did mine. :thumbup:
I am pondering if it is necessary to put fiberglass batts to cover the XPS though.

This is the insulation code in my county:
* Concrete exterior walls shall be insulated with a minimum R-10 insulation
* Wood frame exterior walls shall be insulated with a minimum R-13 insulation. (do you think this is a requirement of the fiberglass batts?)

leungw 01-03-2013 08:55 PM

Quote:

Originally Posted by 325_man (Post 1085612)
This is the insulation code in my county:
* Concrete exterior walls shall be insulated with a minimum R-10 insulation
* Wood frame exterior walls shall be insulated with a minimum R-13 insulation. (do you think this is a requirement of the fiberglass batts?)

2" XPS has R10. I would think a regular basement would be considered concrete exterior and XPS alone should be sufficient for the insulation requirement.

I think they are referring to first floor and above for wood frame exterior. I would check with the inspector though.

Gary in WA 01-04-2013 04:59 PM

As said check locally...

#12; http://www.diychatroom.com/f98/how-f...framing-37190/

Again, local codes change prescriptive codes; if a drop ceiling is lower than the top plate, add fire-blocking in the wall at that level; http://publicecodes.cyberregs.com/ic...002_par017.htm

Wood is only one type of fire-blocking per code; http://publicecodes.cyberregs.com/ic...002_par018.htm

The rims may/not need covering, local again; http://publicecodes.cyberregs.com/ic...016_par015.htm

All the basement walls connected to the drop ceiling require fire-blocking, not just the non-bearing wood wall against concrete wall;http://publicecodes.cyberregs.com/ic...002_par011.htm

Gary

325_man 01-07-2013 08:16 AM

Quote:

Originally Posted by GBR in WA
As said check locally...

#12; http://www.diychatroom.com/f98/how-f...framing-37190/

Again, local codes change prescriptive codes; if a drop ceiling is lower than the top plate, add fire-blocking in the wall at that level; http://publicecodes.cyberregs.com/ic...002_par017.htm

Wood is only one type of fire-blocking per code; http://publicecodes.cyberregs.com/ic...002_par018.htm

The rims may/not need covering, local again; http://publicecodes.cyberregs.com/ic...016_par015.htm

All the basement walls connected to the drop ceiling require fire-blocking, not just the non-bearing wood wall against concrete wall;http://publicecodes.cyberregs.com/ic...002_par011.htm

Gary

Thanks, Gary!
Based on what I read, there is nothing more fire blocking effort that i need to do other than the normal fireblocking requirement with a regular ceiling. Let me know if you don't agree with my conclusion.

I'm checking with local inspector for confirmation. Although, i have tried this in the past and they just don't return calls :(

Nick

325_man 01-07-2013 10:39 PM

Quote:

Originally Posted by leungw

I first replaced the fiberglass in all the joist spaces with XPS. Next I cut drywalls into 10" x 48" strips and secured them on the joists around the perimeter, right against the sill above the concrete walls.

I notice you say 10". Why 10"? The xps is 2" and the 2x4 is only 3.5". So the total is 5.5".

Gary in WA 01-07-2013 11:16 PM

A full-height ceiling would be on top of the single/double top plate of a wall. IF the ceiling is dropped below the top plate, you need to add another row of blocking at the lower ceiling line to prevent a wall cavity fire from traveling up and past the drop ceiling, leaving the wall and entering the space above the ceiling- unless the upper (unused) ceiling plane is drywalled also. Then the fire could travel in the floor joist cavity, across the room, and go up a plumbing chase/hole you forgot to air seal. Many times the plumbing vents go to the roof, if not air-sealed between floors/ceilings, it could set the roof on fire.

Gary


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