Wood framed balcony

[joecode]

Greetings All,

For a new Type VB three story apt bldg(R-2), There will be 6' deep cantilevered balconies
on the second floor. Does this need to be protected? Perhaps under the section of Continuity?

I am providing a 1 hr floor assembly between units and sleeping areas. (fully sprinklered)
Also the exterior walls will be 1 hr since they support the floors.

Owner is cheap, would want deck boards on exposed joists if allowed.

Thank you!

 

[steveray]

There might be something in there on rating them or sprinklering them....13R system? Look more under projections maybe?

 

[joecode]

Looking forward to other comments, but I've pretty much decided to rate it, it's adjacent to a rated wall and connected to
a rated floor so sometimes you just have to make a decision to be safe (and not tell the owner!)

 

[mtlogcabin]

[F] 903.3.1.2.1 Balconies and decks.
Sprinkler protection shall be provided for exterior balconies, decks and ground floor patios of dwelling units and sleeping units where either of the following conditions exists:

1. The building is of Type V construction, provided that there is a roof or deck above.

2. Exterior balconies, decks and ground floor patios of dwelling units and sleeping units are constructed in accordance with Section 705.2.3.1, Exception 3.

Sidewall sprinklers that are used to protect such areas shall be permitted to be located such that their deflectors are within 1 inch (25 mm) to 6 inches (152 mm) below the structural members and a maximum distance of 14 inches (356 mm) below the deck of the exterior balconies and decks that are constructed of open wood joist construction.

 

[joecode]

thank you mtlogcabin!, what do you think about a fire resistance rating?

 

[mtlogcabin]

Check with your AHJ. IMHO you can use fire retardant treated wood or provide a one hour rated floor assembly.

705.2.3.1 Balconies and similar projections.
Balconies and similar projections of combustible construction other than fire-retardant-treated wood shall be fire-resistance rated where required by Table 601 for floor construction or shall be of heavy timber construction in accordance with Section 2304.11. The aggregate length of the projections shall not exceed 50 percent of the building’s perimeter on each floor.

Exceptions:

1. On buildings of Types I and II construction, three stories or less above grade plane, fire-retardant-treated wood shall be permitted for balconies, porches, decks and exterior stairways not used as required exits.

2. Untreated wood and plastic composites that comply with ASTM D7032 and Section 2612 are permitted for pickets, rails and similar guard components that are limited to 42 inches (1067 mm) in height.

3. Balconies and similar projections on buildings of Types III, IV and V construction shall be permitted to be of Type V construction and shall not be required to have a fire-resistance rating where sprinkler protection is extended to these areas.

4. Where sprinkler protection is extended to the balcony areas, the aggregate length of the balcony on each floor shall not be limited.

 

[joecode]

The AHJ is not helpful, doesn't answer emails or calls, won't take a meeting even after the Planning Bd approved the project.

 

[Jay Smith]

It seems like 903.3.1.2 is going to require sprinkler protection so you might as well take 705.2.3.1 exception 3 and provide a nonrated balcony construction.

 

[joecode]

I will look into 903.3.1.2
Project is in New York, (freezes) I haven't seen any sprinklers in similar buildings in this area.

 

[mtlogcabin]

Your choices are:

Fire retarded treated wood
Heavy timber
One-hour rated assembly.
Sidewall dry head sprinkler coverage is how we do it in Montana.

 

[Paul Sweet]

Cantilevered balconies of wood construction are not a good idea. If (or more likely when) water gets in it can rot out the inside structure inside as well as the balcony.

 

[joecode]

Yes, I agree but what do you do when the owner is cheap? California has passed new codes that require ventilation and access panels so you can visually inspect
the framing, I will do that. (even though it's not a requirement in my state yet)

 

[Jay Smith]

Most wood-framed balconies in recent 3-story apartment buildings around me have a concrete topping and waterproofing on wood deck and wood joists or trusses. The underside is usually fiber cement panel. Attaching a photo of an example that was framed out of cantilevered 2x lumber That extends back into the living room floor.