Columbus, Ohio: Fireproof Insulation in Older Homes

[Brad Clarizio]

Hey everyone,

I am working on a major rehab in Columbus, Ohio, specifically in Old Town East for those of you that are familiar. We are just about to call in our first structural inspection so we can move forward with insulation and drywall, but an experienced rehabber friend of mine toured the property last week and called out that we need fireblock between our 1st and 2nd floor. Basically, the house does not have 2x4's blocking the 2 floors, so flames could easily shoot up the sides of the wall. He suggested 2 options:

1: go through and add fireproof 2x4's and use the fireproof spray can foam to seal them (a bit extensive- it's a very large house). 

2: use some sort of fireproof "wool"- he uses stuff made by Owen's Corning but I can't see to find it locally unless I'm commercial, which I'm not. He said he doesn't believe I can use standard fire resistant insulation, but wasn't 100% sure. 

I can't be the first person to run into this issue...what does everyone else do? Suggestions? 

Thanks,

Brad

[Jim K.]

It's an older balloon-framed structure versus more modern platform framing. Yes, your friend is right. The cavities in the wall go from the basement all the way up. This means that a fire that starts in the basement (primary fire point in residential construction) can more easily get air from above to keep burning and also use the cavities to migrate upwards.

A third way this is often done is to use two thicknesses of 1/2 in. drywall cut to size and glued together. Then you go with the fireproof foam. Using fireproof lumber throughout is really going to get pricey. You can also use other materials for fireblocking depending on the building code your community uses. I would investigate.

The rockwool insulation your friend suggests, the stuff made by Owens Corning, is called Pure Safety. You can get it delivered from homedepot.com. It's a bit pricey.

The rub of this is that picking which fireblock method to use really depends on the structure. The 1-inch gypsum board and fireproofing foam is probably going to be cheapest, even though it won't be particularly cheap.