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griffinst 03-04-2011 01:13 PM

Fire Stop ?
 
I just picked up my building permit to finish my basement. The inspector put a stamp on my plan that says...

"FIRE STOP ALL SOFFITS FIRE STOP STUD SPACES OVER 10' & AT CEILING LINE"

What does this mean exactly and what do I need to do so I pass inspection? I do have a 4' x 1' x 40' soffit I'll be framing that runs the entire length of the basement.

Jackofall1 03-04-2011 01:28 PM

Welcome griffinst, to the best DIY'r site on the web.

Your question peaked my interest and with some research here is what I found, really not sure how easily this will be accomplished but it sure sounds like you might want to have like a preinspection prior to closing up the outside of the soffit,

"For fire-stop reasons, soffits must not be open to any wall or ceiling framing. (The goal is to keep a fire in one stud cavity or joist space from using a soffit to jump to an adjacent stud cavity or joist space.) So it's best to install some drywall on the wall or ceiling framing prior to building the soffit, or wait to build the soffit until after the drywall work is done (which, unfortunately, will require a second round of drywall work to rock and tape the soffit)."

This was from: http://www.hometime.com/Howto/projec...ng/frame_4.htm

Mark

DangerMouse 03-04-2011 01:31 PM

This may help as well.

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

DM

baum 03-04-2011 01:36 PM

1 Attachment(s)
Search on here there is a great write up someone did on it. But basically you have to prevent any possible fire from traveling from a stud cavity into the soffit. Some (like myself) i put a 2x4 level with the bottom of the soffit in each stud cavity. you can also accomplish this by using 5/8" drywall and put this from the ceiling down to the bottom of the soffit against the wall. then build the soffit on the outside of the wall. see my example of this below

griffinst 03-04-2011 01:38 PM

Yes that helps. The soffit will be directly against one of the walls. From my research I will be building an L-Shaped soffit. So basically I need to COMPLETELY seal off the soffit with drywall, against the wall the soffit will be on and the floor joists as well?

Jackofall1 03-04-2011 01:42 PM

Quote:

Originally Posted by griffinst (Post 602281)
Yes that helps. The soffit will be directly against one of the walls. From my research I will be building an L-Shaped soffit. So basically I need to COMPLETELY seal off the soffit with drywall, against the wall the soffit will be on and the floor joists as well?

Just a point you might want to call the inspector once this part is complete and before you cover the outside of the soffit, he may say carry on, but then again he stamped your permit, so he may want to see it.

Mark

griffinst 03-04-2011 01:49 PM

Thanks for the image that is really helpful. Do I need to put 5/8" drywall on the top of the soffit as well? Sealing it from the floor joists?

Jackofall1 03-04-2011 01:50 PM

Yes thats the way I read it.

Mark

baum 03-04-2011 01:59 PM

No only against the walls do you need to place the drywall. the ceilings can be left open. The idea is if you have a fire in a stud cavity it will help stop it from spreading into the soffit area.

griffinst 03-04-2011 02:19 PM

The stamp the inspector put on my design also says...

"FIRE STOP STUD SPACES OVER 10' & AT THE CEILING LINE"

What does this mean?

Pretty much all of the walls I'm framing will be over 10' in length. I'm finishing my basement which is 15' x 40'.

I'm also leaving a gap between my wall framing and the concrete foundation to leave room for 3/4" polystyrene that I'm planning on installing behind the framing entirely.

Do I also need to put some 2x4 blocking every 10' to seal 10' sections of wall?

baum 03-04-2011 02:21 PM

No its for walls that are higher than 10'. or if your top plate is higher than the ceiling line. most basement ceilings are below the ceiling line if you are using the trusses for the ceiling

WillK 03-04-2011 02:24 PM

I think that means a wall stud cavity that's more than 10' in height. So if you had 12' ceilings there would need to be a fire block breaking up the wall cavity so there isn't a continuous cavity more than 10' high. And regardless of height, there has to be a stop at the top of the stud cavity.

griffinst 03-04-2011 02:44 PM

Ok, understood. My walls are only 8' so this doesn't apply. However, since I'm framing 5" away from the concrete, I'll have to put some 2x4 blocking next to the top plate to make sure the walls are sealed. Is that correct?

baum 03-04-2011 02:48 PM

If you are going to put your 3/4" foam boards on the concrete behind the studs why would you go out so far? you should have your studs against the foam. why 5" out?

griffinst 03-04-2011 02:51 PM

I'm doing this because foundation walls are not completely square. Mine are pretty close but I want it as close to exact as possible. My room is 40' long so a slight variation would end up showing itself pretty quickly. I used the 3-4-5 method to square up my chalk lines.


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