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View Full Version : Anyone seen this before?


Joe Griffin
03-10-2008, 02:37 PM
I found this today in a basement. If you look closely, someone put a kerf cut in the lower chord section of the joist. Then, a strain gauge or deflection monitor of some type was installed over the kerf. It appeared to be wired to the alarm system, but I couldn't see the end termination, so that is an assumption on my part.

I have never seen this, but would someone want to elaborate if they have? As to why, and exactly what the device is monitoring, deflection, settling, vibration, etc?
David Banks
03-10-2008, 02:45 PM
Someone has way to much time on their hands :)
Michael Larson
03-10-2008, 03:14 PM
Would have cheaper to just sister or nail plate the 2 X.
Dom D'Agostino
03-10-2008, 03:19 PM
It's a floor stress sensor, hooked to the alarm system.

Step on the floor, sensor picks up the movement.

Example here. (http://www.iautomate.com/pulsor.html)
Jim Luttrall
03-10-2008, 03:23 PM
I sure would hate to see someone try to install that on an I-joist.
Joe Griffin
03-10-2008, 03:31 PM
Dom, that was my thought initially, but you confirmed it with the web link. I guess that is the reason for the kerf cut as well, to allow it to flex slightly, therefore setting off the alarm. I should put one of these just under and in front of my refridgerator door! Nah, that wouldn't work, it would be going off constantly with my 18 year old son. Thanks for the tip.
PS had you actually had experience with this or did you google?
Dom D'Agostino
03-10-2008, 03:42 PM
Joe,

I remembered some odd-ball stuff from a huge new construction gig awhile back. The alarm system was quite complicated and I read some of the specs. on the parts and features. These devices were installed on the second floor framing, and on the staircase, so they were visible. Paranoid buyer, as they had different types of sensors almost everywhere in the house.

Dom.
Jerry Peck
03-10-2008, 04:31 PM
My guess is that the saw cut was there, and someone said 'Instead of replacing it or repairing it, let's just see if it sets off a stress gage - I've got one in my garage we can try it with'. :D
Jerry McCarthy
03-10-2008, 05:47 PM
Perhaps it’s the home of Matilda and Babar? :confused: