# Fire-blocking in open porch?



## Green-rev (Jan 28, 2019)

I have a project where we built a porch in front of an existing block building. It was built using a studwall against the block building with posts and headers on the outside wall. The studs were supposed to have been put tight against the building, but because of some pilasters on the building, the contractor laid the wall out with the outside of the studs flush with the outside of the pilaster. The studs were then sheathed with plywood. The AHJ would not do an inspection until after the sheathing was applied, and during the inspection he said that the wall would need fire-blocking. Needless to say, this has caused some consternation, as now the sheathing is going to need to be removed in order to properly fire-block. The question I have is does that wall need fire-blocking? It is only supporting the roof of the open porch. There is a foyer that was also built in front of the entry door, and that is fire-blocked. There is nothing combustible directly above the porch stud wall on the existing block building, it is just a flat wall with no overhangs or projections. Is there any arguement to be made to not require the fire-blocking?


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## cda (Jan 28, 2019)

Even with the word FIRE involved this is a building code question

But. Were the plans showing the fire block

Or is this a change because the plans were not followed


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## Pcinspector1 (Jan 28, 2019)

Is the fire blocking for the vertical walls at every 10-feet or the top of the wall to prevent fire from entering an attic area or soffit area. If fire can enter the soffit and jump into the building through the soffit then that are also would need to be blocked. Also there are numerous products that can be used for blocking, 3/4-inch plywood, particle board and 2X scrap can be used.



Green-rev said:


> The AHJ would not do an inspection until after the sheathing was applied, and during the inspection he said that the wall would need fire-blocking.



Somethings a miss here?

How can he verify the blocking with the sheeting covering the framing?


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## Green-rev (Jan 28, 2019)

It is a change because the plans were not followed. Should I be posting this in a different forum?


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## Green-rev (Jan 28, 2019)

This is for the horizontal requirement of every 10'. There is nothing above the porch roof on the existing building. The porch roof is a flat roof that is constructed of sheathing on the deck and 2x rafters, so there is no issue with the vertical requirement. As stated, the biggest problem is that the sheathing is already installed, so the contractor will have to remove the sheathing in order to install the fire-blocking, at this point.


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## Pcinspector1 (Jan 28, 2019)

If residential: 2012 IRC, 302.11 Fire blocking requirements in combustible construction. Roof space?

Is this a commercial project?


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## Pcinspector1 (Jan 28, 2019)

Polity ask the AHJ for the code section.


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## Green-rev (Jan 28, 2019)

This is a commercial project.


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## Pcinspector1 (Jan 28, 2019)

Pcinspector1 said:


> Politely ask the AHJ for the code section.



Sorry for the misspelling.


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## Builder Bob (Jan 28, 2019)

803.13

First question - does the existing building have to be non-combustible or required to be fire rated  (Construction type or fire separation distance?)


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## Green-rev (Jan 28, 2019)

"First question - does the existing building have to be non-combustible or required to be fire rated (Construction type or fire separation distance?)"
I don't believe it needs to be non-combustible or fire-rated.


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## Pcinspector1 (Jan 28, 2019)

Builder Bob said:


> 803.13
> 
> First question - does the existing building have to be non-combustible or required to be fire rated (Construction type or fire separation distance?)



Should be listed on the plans if commercial. Does the municipality or AHJ do a plan review?


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## classicT (Jan 28, 2019)

Pcinspector1 said:


> Should be listed on the plans if commercial. Does the municipality or AHJ do a plan review?


Does it matter?

Does a lack of comment by the AHJ permit a deviation? See IBC 110.1 -_...Approval as a result of an inspection shall not be construed to be an approval of a violation of the provisions of this code. _

Additionally, ._.. It shall be the duty of the owner... to cause the work to remain accessible and exposed for inspection purposes._


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## mtlogcabin (Jan 28, 2019)

It is required so fill the cavity with an approved cellulose insulation


*CELLULOSE INSULATION*

*What is it?* Cellulose is made of paper products, especially newspaper. The high recycled material content averages 85 percent, making cellulose a good eco-friendly choice. The paper is shredded into tiny pieces and used as loose-fill insulation, especially in oddly-shaped building cavities where batts and rolls aren’t an option.
*How does it stand up against fire?* Paper is highly combustible. To overcome this, cellulose insulation is treated with nontoxic borate, sometimes combined with less expensive ammonium sulfate, for both fire and insect resistance. Proper installation is vital for fire safety, at which point cellulose can withstand temperatures up to 1,200 degrees F.
718.2.1 Fireblocking materials.
Fireblocking shall consist of the following materials:

1.    Two-inch (51 mm) nominal lumber.

2.    Two thicknesses of 1-inch (25 mm) nominal lumber with broken lap joints.

3.    One thickness of 0.719-inch (18.3 mm) wood structural panels with joints backed by 0.719-inch (18.3 mm) wood structural panels.

4.    One thickness of 0.75-inch (19.1 mm) particleboard with joints backed by 0.75-inch (19 mm) particleboard.

5.    One-half-inch (12.7 mm) gypsum board.

6.    One-fourth-inch (6.4 mm) cement-based millboard.

7.    Batts or blankets of mineral wool, mineral fiber or other approved materials installed in such a manner as to be securely retained in place.

8.    Cellulose insulation installed as tested for the specific application.



718.2.2 Concealed wall spaces.
Fireblocking shall be provided in concealed spaces of stud walls and partitions, including furred spaces, and parallel rows of studs or staggered studs, as follows:

1.    Vertically at the ceiling and floor levels.

2.    Horizontally at intervals not exceeding 10 feet (3048 mm).


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