Help with code in garage attic

[Mtavares08]

The job is in unincorporated Alameda County
We’ve recently converted a flat roof into a pitched roof over our family room. The new attic space now extends partially over the garage to the ridge. However, we’re uncertain about the proper fire separation for this configuration.

Currently, the old roof rafters have gaps and are exposed, allowing the attic space over the family room to vent into the garage and vice versa. Additionally, we created an attic access and isn’t fire-rated.

I’ve found references to R302.6 and CRC R807.1, but I need clarification to ensure we’re compliant.

Does anyone have suggestions on how to address this properly?

 

[steveray]

The attics can be connected, but typically somewhere is a "continuous" drywall barrier separating the garage from other areas....And we get picky on ductwork penetrations...

 

[SCBO1]

First, you should have had a plan review from the permitting authority and permit for construction, with that said the plans should have indicated what's needed for separation. Usually 5/8-inch Type-X drywall is used.

Question, does the garage have a drywalled ceiling and walls separating the garage from the main part of the house or is this a "Dan Tanna, set-up!" (Old TV show, look it up!) where you can drive your red s[ports car into the living room?

If the house is a standard ranch style house with a garage on the end, there should be a wall between the garage and the main house that has drywall attached that goes all the way up through the attic following the roof pitch. Sometime the garage ceiling in older homes has exposed ceiling joist, if this is the case you will need the wall extending to the rafter slope in the attic.

If this is a split entry home with bedrooms above a garage the garage ceiling would have a minimum of 5/8-inch Type-X drywall and any supports like beams or post would need protected. The beams and post will typically be covered with 1/2 or 5/8 drywall. You are essentially making the garage a cocoon.

You will need to verify with the permitting authority if there has been any amendments to the codes.

 

[Mtavares08]

Look at the picture you can see I have there is no separation from the garage to attic other than the rafters. And the wall that is drywall we is the walls that are adjacent to the living areas in the garage

 

[steveray]

Look at the picture you can see I have there is no separation from the garage to attic other than the rafters. And the wall that is drywall we is the walls that are adjacent to the living areas in the garage

If the garage airspace connects to the attic airspace over the dwelling, it's a problem...You either have to do the garage as a box with a lid or the drywall goes to the roof deck at the common wall to the dwelling unit...

 

[SCBO1]

From afar, pictures indicate you do not have "rafter ties" at a minimum of every 48-inches.

 

[steveray]

From afar, pictures indicate you do not have "rafter ties" at a minimum of every 48-inches.

I wasn't going into the all of that......Some weird framing I don't fully understand but looked original....

 

[Mtavares08]

Here some more pic

 

[Mtavares08]

They built the roof frame over the existing roof rafters all the way to the top of the ridge in the garage

 

[ICE]

It appears that there shall be a wall in the new attic space that has 1/2" drywall. The wall shall block any communication between the dwelling attic and the garage. The wall shall be located directly over the existing wall that separates the dwelling from the garage.