I did a search on Breaktime and found a ton of information, but have a question regarding drywalling in garages versus basements where the exterior walls of the house are less then 3′ from a neighboring house.
Both the garage and basement (that connects to the garage) have exterior walls that is less then 3′ from a neighboring house’s exterior wall.
My understanding is that garage needs a 1-hour firewall, hence I was planning on 2 layers of 5/8″ drywall (one layer on top of the other) on the wall the faces the exterior wall. It will be taped and mudded.
There is a door between the basement and garage, so there are separated.
My question is will the exterior walls in the basement that are within 3′ of a neighboring houses walls also require 2 layers of 5/8″ drywall?
I’m not certain whether a 1-hour rated wall is only necessary in a garage or at anytime there is an exterior wall that is less then 3′ from a neighbors.
Also above the garage is the kitchen. Will the exterior walls in the kitchen also require a 1-hour rated wall?
Thanks in advance for any insights.
Tark
Replies
"My understanding is that garage needs a 1-hour firewall, hence I was planning on 2 layers of 5/8" drywall (one layer on top of the other) on the wall the faces the exterior wall. It will be taped and mudded."
You need to find out what specific code and amendements tht you local has adopted.
For example the 2000 IRC only requires one layer of 1/2" DW on the garage side of a common wall between the garage and residence.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Bill,Thanks for responding.
My research from the building department's website indicate they adopted the 2001 California Building Codes and the 2001 California Fire Code, among others. The only amendments they have on the issue are for the use of 5/8' drywall on the walls and ceilings separating the garage from the rest of the structure. There was nothing specific regarding requirements for exterior walls that are within 3' of a neighboring house's wall, which is what I am trying to figure out. I know I could call the department, but wanted to hear from the forum to gain as much knowledge and educate myself a bit.Tark
"My research from the building department's website indicate they adopted the 2001 California Building Codes and the 2001 California Fire Code, among others. "
Tark, Part 2 of the 2001 CBC is what you are referring to, and is an amended version of the 97 UBC. It applies to all permits taken out after 11-01-02.
There was nothing specific regarding requirements for exterior walls that are within 3' of a neighboring house's wall, which is what I am trying to figure out.
The reference you are looking for is in Chapter 5, General Building Limitations, table 5-A, Exterior wall and opening protection based on location on property.
If your Occupancy is R-3 (dwelling) and construction type is V-N (most single family dwellings fall under this type) then both exterior bearing and non-bearing walls less than 3 feet are required to be 1 hour rated. Not rated elsewhere. (3 feet or more) Openings are not permitted less than 3 feet. These distances are based on property lines, not on distance from a neighboring house's wall.
My understanding is that garage needs a 1-hour firewall, hence I was planning on 2 layers of 5/8" drywall (one layer on top of the other) on the wall the faces the exterior wall. It will be taped and mudded.
Take a look at chapter 3, 302.4. exception 3. That's where the 1 hour occupancy separation comes into play. It calls for 1 hour fire resistive construction on the garage side (typically you see 1 layer of 5/8" drywall in this application) and a self closing, tight fitting door having a rating of not less than 20 minutes. This is permitted in lieu of a normal one hour fire assembly. (one with 5/8" rock on both sides). This separation also applies to occupied space above the garage.
This is the basis for the questions you are asking, but any or all of it could change depending on what exact spot you are building in California. I live in Sacramento, and each jurisdiction, city and county, have there own local amendments to the CBC, so it would really be in your best interest to discuss this with your local building department.
Panic,Thanks for the more detailed info. I have a call into the building department, and also plan on visiting the library to look up the chapters you called out.Thanks,Tark
The gypsum board used on the outside, under the siding, has to be the special sheathing panel with the brown facing paper. Inspectors here care about this.Bill
Bill is right - You need to check your local codes.
Firewall codes often have very little basis in reason, and seem to vary widely in what they require and whether they're enforced or not.