I have a question on cross-bracing I-joists for a newly constructed home. The I-joists are 11 7/8″ on 16″ centers with 3/4″ plywood on the floor. The maximum span is around 18 feet on any part of the floor. Just wondering if cross-bracing will help make the floor stronger? When is the best time to attach the bottom ends of the cross-bracing, after the finished flooring or before? What is the best material to use for cross-braing? Should the cross-bracing go up to touch the under side of the plywood? Should the bracing be every 8 feet? Should I use strapping on the under size of the I-joists as well? Thank you.
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Replies
Perpendicular strapping 2 16" OC can take the place of blocking at 8'. No need for both.
for most of your questions, I have to ask, what did your plans detail?
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Plans?
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"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
I-joists don't need cross bracing.
And BTW - Cross bracing doesn't make a floor stronger - It just helps control vibration.
More info on floor vibration here:
http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=21010.1
I thought cross bracing added some degree of load transfer.
Family.....They're always there when they need you.
Cross bracing was used prior to the use of construction adhesive. It was used to transfer loads to multiple joists. With the advent of construction adhesive as a weight is placed at a point pressure down is carried to the adjacent joist on each side. The second joist from the weight sees an up pressure. This could not happen with nails only because they would pull up. With construction adhesive the weight is always supported by 5 joists. To answer your question about installing cross bracing. Nail the bracing to the top of the joist as high as you can. When the house is complete or at least the drywall stocked then nail the bottoms.
Transfer to what?
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"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
The other joists.
Family.....They're always there when they need you.
Must not play a role in I-joist performance. Not one single mention of it in all the detail of the 24-page Specifier's Guide available for download from Weyerhaeuser's I-Level website.
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"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
Cross bracing keep the bottom of the joist from rolling when under stress.
Strapping or drywall can do the same.
Load sharing would be the term you wanted.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Thank you.
Family.....They're always there when they need you.
Try googling 'IBS2000 X-bracing'
Not sure how much hey cost, but look like can dramatically increase floor stiifness.