[mattlreese]

I am building a deck that has a slight bounce. Its built to code. 2x8 joists, 12oc, 12 ft span (13 is max). Deck beam is double 2x10, 5 ft span. Decking is Cumaru (a hardwood), 5/4x6 at an angle. I do have blocking but its not quite in the middle and not perfectly offset.

It feels more like the hardwood transfers too much of my walking energy causing some vibration.

Outside of adding another beam what can I do here? I was thinking of adding another row of blocking.

 

[joecaption]

Post a picture.
Trying to picture how the beam only has a 5' span.
You did space the joist 12' or less O/C since your running the boards at an angle, right?
That's a long span for only a 2 X 8, code or not.

 

[mattlreese]

https://photos.google.com/photo/AF1QipPloszCZDULikzG83T6lKK0hz2i-SeGZdE3-Sfi

https://goo.gl/photos/NYjitaMHyBapnuKg8

https://goo.gl/photos/cRuivUY9joB5AZ5E8

In retrospect I would agree about the span, if I did this again I would do it differently.

 

[Bud9051]

Another row of blocking might help a little, but will not be enough to justify the effort. A second carrying beam under the middle with 3 more support posts would be perfect.

My family room has 2x10's spanning 13 feet and my 10 pound dachshunds cause it to bounce when they trot across. It won;t fall down with 2x8's, but it will bounce.

You could try to just stabilize the central area with just 2 support posts and a shorter carrying beam.

Bud

 

[jlhaslip]

Needs more Cowbell ... er, blocking, I mean.
Joe is correct. Even though 2x8 is in the chart for acceptable joist size, those charts are Maximum and as you come close to the maximum spans, you are better off spacing them closer or upsizing them to the next bigger material. Code is the minimum standard.
Actually, possibly adding strapping underneath might helps as well.