Plywood on the sanctuary roof: seismic integrity (Condition Report)

PLYWOOD IS THE KEY to the seismic integrity of our sanctuary building, according to three structural engineers I have spoken with. Although no plywood seems to have been employed in its original construction, a layer was added overhead in 2004 during a re-roofing effort, as discussed elsewhere in this blog. 

As of this past week, I can say with confidence that the roof’s plywood is adequate to ensure that our building provides at least a minimum life safety level of performance in the event of a serious earthquake. 

Cross-section in a cut at the walkway alongside the roof's barrel,
showing 3 layers: plywood, sheathing, and rafter.
(I added a typical nail for comparison—but placed it too low.)

Last month, in the process of making structural repairs to the roof, enough plywood was exposed that I was able both to see the size of the nails employed and to measure the nailing pattern used. Those two factors affect the seismic integrity of the roof. 

Below the jump, I show and discuss my findings, while looking ahead to similarly strengthening the walls.…

Limits on construction noise in L.A. (Background Report)

CONSTRUCTION-RELATED NOISE is forbidden by law within the City of Los Angeles (i.e., at Mishkon) before 7:00am or after 9:00pm. That is, any such noise that is loud enough to disturb nearby residents. It includes the delivery of construction materials. (LAMC 41.40a)

Such noise is likewise forbidden within 500 feet of residential buildings on Sundays, as well as on Saturdays or holidays before 8:00am or after 6:00pm. (LAMC 41.40c)

Mishkon does have neighbors who reside nearby: next door, across the street, and down the street within 500 feet.

For details (and the penalty for violation), see the municipal code:

https://codelibrary.amlegal.com/codes/los_angeles/latest/lamc/0-0-0-128777#JD_41.40.

Duct smoke detectors: required in the sanctuary’s HVAC system? (Background Report)

A DUCT SMOKE DETECTOR is an HVAC-system device that can prevent flames and smoke from being spread or fanned by the system. In the event of smoke, the detector sends a signal to shut down the fan. Its presence is required by code in most circumstances. Normally the determination is made by city building department officials when a permit is applied for. 

The HVAC contractor Jessy Perets told me that our sanctuary’s HVAC system lacks duct smoke detectors. He also pointed out that our twin HVAC units were installed in a visibly low-budget manner, apparently without a building permit. Which has led me to wonder whether or not a pair of duct smoke detectors were technically required in our case. 

For a fire safety measure, the fact of requirement (if it indeed exists) would argue for installation after the fact (which would cost $1,275 as quoted by one contractor). Conversely, if our case is an allowable exception, that would argue for leaving things as they are. At its June meeting, the board adopted that approach and asked the B&G Committee to find out whether duct smoke detectors are required by code in our sanctuary. 

I have a provisional answer, which I lay out below the jump.…

Historically significant features in the Social Hall and main corridor (Background Report)

CHARACTER-DEFINING FEATURES of our historic sanctuary building were identified in the Historic Structure Report (2003; “HSR”). These are the aspects that warrant historic preservation, in the eyes of architectural historians.

Below the jump, this post excerpts from here and there the HSR to describe and list the historically significant features in two spaces that some members are reportedly eyeing for decoration. As named in the HSR, those spaces are known as the corridor (B-01) and the Social Hall (B-02).