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  1. #1
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    Default Question: what are these braces/supports called and are they structural?

    Hello all,

    Thank you for being such an informative community. I do have a question (I searched the board prior but didn't find an answer): Can someone help me identify these diagonal pieces of wood that exists only on one side of my garage? The wood goes from the side of the garage and the ceiling of the garage (which is the support of the second floor).

    I live in San Francisco so I'm not sure if it was related to a seismic upgrade from a previous owner. Contractors have told me they are safe to remove but without even knowing what they are called, it's challenging for me to do my own research. The other side of our home is finished and these diagonal pieces of wood aren't there. I would like to either remove them or replace them with an alternative support that would allow me to use more of the vertical space on the wall.

    garage - 1.jpeggarage - 2.jpeggarage - 3.jpeggarage - 4.jpeg

    Please see the attached photos. Any help is appreciated!

    Thank you

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  2. #2
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    Default Re: Question: what are these braces/supports called and are they structural?

    I would agree with Barry that out there it could be some sort of earthquake retrofit.
    Around here you would see that on an old garage that has started to lean one way. The braces would be intended to stop the garage from leaning more in that direction.
    How's the ground outside of that wall? Does it slope down and out, is there a lot of erosion?

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  3. #3
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    Default Re: Question: what are these braces/supports called and are they structural?

    Quote Originally Posted by BARRY ADAIR View Post
    i'd note as diagonal wall braces in a report
    doubtful as seen a seismic retrofit
    send a "request for information" to sfbd w/pix to the bldg inspection department
    or look up possible permit online
    you say the wall is shared with the living space
    insulation and properly installed gypsum board, for the now, required fire protection & plywood panels would benefit you for heat loss & seismic retrofit consult sfbd and a competent contractor for further info
    assuming there is living space above, the ceiling should be covered with 5'/8" type x gypsum board for fire as well

    1707 haight in the 60s
    Thank you for the fast response! I did check for older permits and there are none. So I assume it was either original or maybe added later w/o permits. Thanks for the suggestions on the required fire protection. This is definitely something we want to add soon. We do have a fair amount of electrical boxes and conduit attached to the studs, would you recommend we have an electrician redo the conduit so we can drywall or could we just drywall around the conduit?

    Quote Originally Posted by Markus Keller View Post
    I would agree with Barry that out there it could be some sort of earthquake retrofit.
    Around here you would see that on an old garage that has started to lean one way. The braces would be intended to stop the garage from leaning more in that direction.
    How's the ground outside of that wall? Does it slope down and out, is there a lot of erosion?
    Thanks for responding! The other side of that wall leads to the neighbor's property. Our lot is relatively flat but the street our home is on has a slight slope going towards that wall.

    Assuming we can't or maybe shouldn't remove the braces, another option we've thought about is shortening them. If we keep the same angle (it appears to be 45 degrees) and just shorten them so they fit tighter up top and take up less space. Would this be considered OK?


  4. #4
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    Default Re: Question: what are these braces/supports called and are they structural?

    Patrick,
    My first thought when looking at the pictures is that those could have been added to support the upper floor due to having a long span (don't know how long those joists are above the garage) or just take the play out of a bouncing floor. Looks like they did a nice job adding the support braces.

    Badair _ I was also in Haight in the 60"s Summer of Love.


  5. #5
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    Default Re: Question: what are these braces/supports called and are they structural?

    Quote Originally Posted by Gary Burnett View Post
    Patrick,
    My first thought when looking at the pictures is that those could have been added to support the upper floor due to having a long span (don't know how long those joists are above the garage) or just take the play out of a bouncing floor. Looks like they did a nice job adding the support braces.


    Badair _ I was also in Haight in the 60"s Summer of Love.
    Gary - thanks for the response! The floor joists above are 11 feet. The bouncing floor bit sounds interesting... as far as I can tell we don't have that issue (or maybe that means these supports are doing their job).


  6. #6
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    Default Re: Question: what are these braces/supports called and are they structural?

    Quote Originally Posted by BARRY ADAIR View Post
    cutting & tape & bedding around conduit & boxes is a pita
    having worked numerous trades, i personally would remove-retrofit the conduit & the addition of any needed outlets myself after drywall finishing
    garages now require all receptacles to be gfci protected either by device or breaker
    Thank you for the advice!

    Quote Originally Posted by BARRY ADAIR View Post
    the braces were placed for a reason, yet to be determined, you're possibly getting into re-engineering & an engineer would be the best to advise
    That makes sense. We'll reach out to some local structural engineers and see if they can do a physical assessment. Thank you for your help!


  7. #7
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    Default Re: Question: what are these braces/supports called and are they structural?

    Also keep in mind that (per the IRC, not sure about the CRC) with living space above the garage, the ceiling needs to be minimum 5/8" Type X gypsum board (drywall), which would need to be behind the conduits and other things; and minimum 1/2" gypsum board on the walls supporting the floor/ceiling assembly between the garage and the living space above, and would also need to be behind the conduits and other things.

    With those diagonals, the drywall would need to run up the wall behind the diagonals, and if those diagonals are there for support of the floor ... or ... the wall, those diagonals would also need to be protected with 1/2" drywall (protected on the garage side, which would leave an empty furred out space behind the diagonals, with 1/2" drywall on the walls in that furred out space), or wrap the diagonals in /2" drywall and possibly gain some storage space behind the diagonals ... except that you are sure what their purpose is, or how much load would be allowed to be placed on the diagonals (fishing poles and other lightweight would likely ... likely ... not be an issue, but stacking boards and other things there may create an over-loading issue on the diagonals.

    The diagonals look to be 1x instead of 2x, but at least the 1xs are used in pairs on the studs, but only on every other stud.

    And, any wall between the garage and the dwelling needs to be covered with minimum 1/2" drywall applied to the garage side of those walls.

    The more this is discussed, the need (as Barry said) for an structural engineer to review it increases.

    Just more food for thought.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  8. #8
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    Default Re: Question: what are these braces/supports called and are they structural?

    I didn't want to overload too much at one time, but ...

    Being as that is living space above the garage ... the floor above needs to be insulated at that is the thermal envelope of the dwelling, with a vapor barrier (which actually a vapor "retarder"), if one is present, needs to be placed to the appropriate side (used to be 'facing the warm in winter side', now things are not as clear cut), and the insulation needs to be in contact with the floor above (otherwise cold or hot air will get above the insulation and reduce or even negate the insulation's effectiveness).

    Jerry Peck
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    www.AskCodeMan.com

  9. #9
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    Default Re: Question: what are these braces/supports called and are they structural?

    Those diagonal braces are pretty common in S.F. garages and I believe are original to the home, rather than a retrofit. I don't do a lot of S.F. inspections, and have not followed-up to find out what purpose they serve (other than bracing something). If the front elevation of this home matches many other S.F. homes, the vehicle door opening is single-wide and offset, but the garage area is often two cars deep.

    For those in other parts of the country, wood-frame home construction in CA is typically platform rather than balloon (although both were used in S.f.) Since this is on the side of the garage that has a narrow support wall (and therefore potentially less shear value), it may well have been something that the builders felt would strengthen the home seismically. There is a high probability that this is post 1906, and many builders were trying "common-sense" approaches to build homes that were seismically resistant. Even though it was the fire that did most of the damage, the earthquake generally gets the credit.

    The braces may also provide some stiffness to the floor joists, as Gary already stated. The joists appear to be 2x8, but I can't tell for sure. If 2x8 douglas fir on 16" centers, then an 11' span should be fine, but might flex a bit. However, I would think that bracing diagonally to the wall would tend to cause the wall to flex (maybe not enough to be noticeable). If the joists are redwood, then 11' might be pushing the limit of the allowable span (I don't know know the redwood spans).

    I would be reluctant to remove or modify the braces without knowing more. I am with Barry and Jerry here, best bet would be to hire a structural engineer (P.E.) to take a look and make a judgement. Since there are so many fault lines in your area, you might also want to have the engineer design seismic retrofits to current standards.

    Quote Originally Posted by Jerry Peck View Post
    Also keep in mind that (per the IRC, not sure about the CRC) with living space above the garage, the ceiling needs to be minimum 5/8" Type X gypsum board (drywall), which would need to be behind the conduits and other things; and minimum 1/2" gypsum board on the walls supporting the floor/ceiling assembly between the garage and the living space above, and would also need to be behind the conduits and other things...

    And, any wall between the garage and the dwelling needs to be covered with minimum 1/2" drywall applied to the garage side of those walls.

    The more this is discussed, the need (as Barry said) for an structural engineer to review it increases...
    Sort of, kind of. Jerry is correct, the CRC does require 5/8" Type X drywall on the ceiling and 1/2" drywall on the supporting walls and walls that are common to the living space in new construction. However, existing homes are not required to upgrade, unless performing other work in that area. As such, if you do choose to remove those diagonal braces, you would be obligated to drywall the ceiling and walls. Certainly, insulating and sheathing the ceiling and walls is good practice in any case.

    Quote Originally Posted by Jerry Peck View Post
    ... the floor above needs to be insulated at that is the thermal envelope of the dwelling, with a vapor barrier (which actually a vapor "retarder"), if one is present, needs to be placed to the appropriate side (used to be 'facing the warm in winter side', now things are not as clear cut), and the insulation needs to be in contact with the floor above (otherwise cold or hot air will get above the insulation and reduce or even negate the insulation's effectiveness).
    Again, existing home. Insulating will save money and is certainly a good idea, but unless other work is being performed, it is not required. The state and utility companies were offering incentives to insulate older homes at one point. Not sure if that is still going on.

    Around here, most of the fiberglass batt insulation that is faced with a vapor retarder is sold through the "big box" stores to homeowners. Insulation contractors do not use faced batts, unless specified in the plans. My understanding is that this is because we are essentially a dry climate (I know, S.F. really isn't dry, but CA doesn't have the humidity issues of many other parts of the country. As a result, most CA residential construction is built with unfaced batts.

    Last edited by Gunnar Alquist; 12-07-2020 at 10:49 AM.
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  10. #10
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    Default Re: Question: what are these braces/supports called and are they structural?

    Thank you Jerry and Gunnar for the added input! Gunnar - you're exactly right about the layout of our home: the garage is two cars deep on one side. Also, the home was built in the late 60s. The feedback from this thread has been very insightful! We are definitely holding out on removing/modifying the braces until it can be evaluated.


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