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.

[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.

[Brad Clarizio]

Thanks Jim- I do plan to call the city today as this just transpired over the weekend. 

He mentioned that I only had to do about 12-18" between the floors, and then of course standard insulation through the rest of the walls. Is that your understanding as well? I can't imagine it being too expensive for any option- it's probably about 100 feet worth of 2x4's if I did it that way. 

[Jim K.]

Definitely call the city first and get whatever info they're willing to share first. A warning -- there are a LOT of yahoo contractors and shady moneymen in this side of the business that are just looking for a way around what they see as unnecessary code requirements. Of course, local code officials are the first people the hammer comes down on when structures burn, so they hate the yahoos. Don't be a yahoo and you'll be fine with them. Give off a whiff of yahoo and these officials can get weird.

Here's the situation in the City of Pittsburgh for new construction: a piece of fireblocking goes in at 10 feet maximum between floors in wall cavities. Standard insulation is not required for fireblocking -- it's nice, of course, as part of any rehab, but not a fireblocking requirement compliance issue.

Regular 2x4s are probably not going to cut it in your area. You're probably going to need fire-retardant pressure-treated lumber. This is difficult to get in my area. 1/2 in. drywall, on the other hand, cut to the right size and doubled up, is dirt cheap.

The foam, and you are almost certainly going to need it to be compliant, is what's going to cost you the most if you go that way. The most usual way is to go with Great Stuff Fireblock. It's almost twice as expensive as the regular Great Stuff.

Good luck, Brad. The local municipality's code compliance officials all know best. They can make you hurt if they choose to. Keep those relationships professional, respectful, and open.

[Charlene McNamara]

I wouldn't worry about it too much until you speak to county or city code compliance in your municipality. We've had similar issues in the past and the county gave us several options as work arounds. They're the ones who are going to have to sign off on your permit, so, honestly, the only thing that matters is what they say.

[Brad Clarizio]

@Jim K.- thanks again, very helpful. 

@Charlene McNamara- thanks for the advice, but we want to have this done before our first inspection so we can move forward with drywall, and if it fails (which it would because of this), we're delayed. It'll get flagged for sure. May as well be proactive. 

[Charlene McNamara]

Of course, but usually you can go to the building department and ask. In my area, we can just walk in and take a number then wait to chat with a desk jockey who will tell us what will be required to pay inspection.

[Charlene McNamara]

autocorrect error....what will be required to PASS inspection.