Thread: 1994 Townhouse Firewall

Recently, inspected a townhouse with a 1 hour rated firewall that included a 4 foot wide fire rated roof deck. There were exhaust vent and ridge vent penetrations in the fire rated roof deck. I wrote these penetrations are code violation, however, the HOA roofer is saying they are acceptable.

Also, the fire rated roof deck is delaminating and the attic side of the roof deck has a white coating, not familar with this product.

Assistance would be greatfully appreciated.

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Originally Posted by Jack Wingo

Recently, inspected a townhouse with a 1 hour rated firewall that included a 4 foot wide fire rated roof deck. There were exhaust vent and ridge vent penetrations in the fire rated roof deck. I wrote these penetrations are code violation, however, the HOA roofer is saying they are acceptable.

Also, the fire rated roof deck is delaminating and the attic side of the roof deck has a white coating, not familar with this product.

Tried to upload a photo but file was too big and did not know how to reduce.

Assistance would be greatfully appreciated.

As long as the penetrating objects are 2 hour rated themselves should be no problem.

Was able to reduce photo size. Is this FRT plywood with a white coating?

Originally Posted by Tom Thompson

As long as the penetrating objects are 2 hour rated themselves should be no problem.

Tom, a roofing contractor, is saying 1991 SBC Table 1001.3 allows roof membrane penetrations without added protections. To me this does not make sense!

What code does Florida use?

Assuming we are using the IRC here: The 1-hour wall goes to the roof deck. Openings in the sheathing do not need fire protection.

FRT plywood is not required and that is not what is pictured. I have never seen that white material before. It appears to be a roll material and it is water marked. The roof sheathing above it appears to be water marked or moldy.

Don't know what code or edition was in effect in 1994 in that jurisdiction, but the 2009 IBC states:

706.6 Vertical continuity.

Fire walls shall extend from the foundation to a termination point at least 30 inches (762 mm) above both adjacent roofs.

Exceptions:

1. Stepped buildings in accordance with Section 706.6.1.

2. Two-hour fire-resistance-rated walls shall be permitted to terminate at the underside of the roof sheathing, deck or slab, provided:

2.1. The lower roof assembly within 4 feet (1220 mm) of the wall has not less than a 1-hour fire-resistance rating and the entire length and span of supporting elements for the rated roof assembly has a fire-resistance rating of not less than 1 hour.

2.2. Openings in the roof shall not be located within 4 feet (1220 mm) of the fire wall .

2.3. Each building shall be provided with not less than a Class B roof covering.

3. Walls shall be permitted to terminate at the underside of noncombustible roof sheathing, deck or slabs where both buildings are provided with not less than a Class B roof covering. Openings in the roof shall not be located within 4 feet (1220 mm) of the fire wall .

4. In buildings of Type III, IV and V construction, walls shall be permitted to terminate at the underside of combustible roof sheathing or decks, provided:

4.1. There are no openings in the roof within 4 feet (1220 mm) of the fire wall ,

4.2. The roof is covered with a minimum Class B roof covering, and

4.3. The roof sheathing or deck is constructed of fire-retardant-treated wood for a distance of 4 feet (1220 mm) on both sides of the wall or the roof is protected with 5/8-inch (15.9 mm) Type X gypsum board directly beneath the underside of the roof sheathing or deck, supported by a minimum of 2-inch (51 mm) nominal ledgers attached to the sides of the roof framing members for a minimum distance of 4 feet (1220 mm) on both sides of the fire wall .

The exposed area of that decking looks wet.

Jack,

Along with concerns about that loose white stuff (whatever it is) is that the protection of the underside of the roof deck is/was required for 4 feet each side of the wall (and the 4 feet is not measured from the center of the wall, it is measured from each side of the wall), and to be protected there must not be any penetrations within that 4 feet.

Back then, the codes were still maturing on fire-rated protections and penetrations, and a penetration may have been allowed if the penetration was non-combustible (such as cast iron DWV pipe) and the opening around the penetration sealed and firestopped with what was in use back then. Another example of an allowed penetration, back then, may have been an exhaust duct made from minimum 26 gage metal and also sealed around.

"Back then" the codes were still growing in complexity by leaps and bounds with regard to fire-resistance ratings and fire-resistance protection.

Has the HOA roof provided a copy of what they say was in effect at the time? If they cannot produce it, I would consider that it did not exist as it may very well be someone "remembering something someone told them" back then.

That is called Blaze Gaurd, and to tell you the truth it surprises me there was never a class action law suit. I have seen that crap fall apart from leaky bath vents with good passive roof venting... poor pasive roof venting and to tell you the truth I wonder if in just plain humid enviroments causes it to fail, theres never been 1 smokin gun to say why it fails. I would be curious if any one out there in the south west dryer climates observes this product and if so,what was the conditions.

also it sucks in moisture, so it can always appear to be a roof leak, its like a calcium chloride that will stain the drywall ceiling and many times roofers are called in for a roof leak and its that crap dripping.

When I Google'd the name "Flame Guard", I found the manufacturer, International Barrier Technology. Here is their explanation of how this stuff is made. (Apparently Flame Guard and FlameBlock are the same thing.)

The unique Pyrotite® ignition-resistant coating on LP FlameBlock Sheathing is our secret weapon against fire. Covering an LP® OSB panel, the Pyrotite coating is a layer of non-combustible magnesium oxide with two quarts of water chemically locked into every 32 square feet of the coating's structure in the inert form. The bound water is released when exposed to the intense heat created by fire. Once released, this moisture helps LP FlameBlock Sheathing resist burn-through and slow the spread of fire.

An example of its fire resistance was pretty impressive, but I didn't find anything on their website about a tendency to release water prematurely, or to attract additional water. Go figure!