Fire Stop Construction

Very useful and helpful website. Also easy to understand. Thanks!

Tim,

Great website! One question here -- I'm about to frame my basement, and I read one of your other articles about how one should leave a little air space between the studs and the concrete or masonry wall. Seems after reading this article, that strategy makes any fireblocking in those walls useless, because the fire can spread to other parts of the wall through the space between the studs and the wall. Or will fiberglass insulation batts provide an effective fireblock because they will push up against the concrete wall?

Steve,
You are correct. It is nearly impossible to firestop walls like that.

So if it nearly impossible, how would you propose to build a firestop in the offset wall senerio when finishing a basement?

JB,
This qualifies for a phone consult. I could type for 30 minutes or more.

i have put a 9in wall to seperate the building i need to put a fire stop on top of the wall what should i use steve

Hi. The fire wall separating my townhouse's basement from my neighbor was not completed correctly in 1975. All odors/noise (cigar smoke, litterbox odors, etc.) from my neighbor spread to my basement (and up the stairs), and I'm very concerned that a fire in their basement would spread to mine. The concrete block appears to be solid from floor-level to just below the ceiling in the laundry room. Above the concrete block is narrower gypsum board. A friend thinks that air is traveling into the opening of the concrete block, then beneath the gypsum board, and up through the concrete block holes of the other townhouse. Also, the sheets of gypsum board have a 1/2" gap between them. What can I do to close these gaps? Is the fireproof caulk (tons of it) that you've mentioned appropriate, or mortar, or something else? Thanks.

Hello, I am in the same situation as JB as i am finishing my basement and my 2x4 walls are offset from the foundation walls. I can spray foam around the header to create a firestop but that does not help to contain any fire from spreading to other cavities. Any advice is greatly appreciated.

What we do when we frame basement walls, is put a 1x8 up against the joists tight to the mudsill, then nail a 2x4 plate to that and frame our wall. This way we are off the concrete, but the walls are sealed from the joist bays. Then every 10' of wall, we nail another stud that is about 1/4" off the concrete. The gap gets foamed by the insulation contractor or us.

http://pic40.picturetrail.com/VOL293/2163851/7154567/328859972.jpg

Thank You. I was going to use spray foam to seal the gaps.

Tim, Does code require firestops between the floor and the wall or just where one floor meets another.

I too have build walls away from foundation rendering stops irrelevant. Any way to hear what you told the other steve. Thanks, Steve too.