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[SEAOC] Re: [SEAOC] UBC Sec3102.6

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Dear Tom:

Los Angeles city does not require the chimneys to be braced if the height
from the base to the roof is greater than the height from the roof to the
top of the chimney. This is usually true in two story homes with mild slope.

Also, I believe that Harlen has chimney braces which comply with UBC

Hope that helps.


At 04:12 PM 11/11/96 -0500, you wrote:
>     I would like to know what others are doing to comply with the "94
>Uniform Building Code  Sec 3102.6 on wood chimneys for  metal pre-fab
>fireplaces in houses. This is typically a sheet metal round flue inside 2x
>wood frame rectangular chimney which is typically stuccoed or  brick veneered
>     This is new to the ('94) code. In the past i have been using simpson  cs
>straps but they are not 1/8" thick ( 11 gauge ). It would appear only Simpson
>mst60 or 72 are thick enough but they will not " loop  around " well.  Also ,
>the code is not clear about how far into the roof or floor to extend the
>straps. I have been going 6'. I assume the code is refering to looping around
>the outside of the wood chimney, not the metal flue inside. Also it would
>only make sense to apply to exterior not interior chimneys ( different
>problem there ).
>     In looking at tracts around town here it appears no one is complying
>with this section at all. This did seem to be a problem i saw when providing
>earthquake damage reports after the Northridge earthquake, especially when
>the chimneys were tall as with steep pitch roofs or a nearby 2nd story.
>     I would value your opinion on this subject. I may be misunderstanding
>this section.
>Tom Harris, SE
>Thousand Oaks, CA
>94 UBC Sec 3102.6  2nd Para, page 1-375 of vol 1 :
>    Metal chimneys shall be anchored at each floor and roof with two 1 1/2-
>inch by 1/8 inch metal straps looped around the outside of the chimney
>installation and nailed with not less than six 8d nails per strap at each