Floor Bounce How do I Get Rid of It?

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Topic by cpt_hammer posted 01-13-2009 06:23 PM 25959 views 0 times favorited 6 replies Add to Favorites Watch
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6 posts in 5520 days

01-13-2009 06:23 PM

Topic tags/keywords: question kitchen basement dining room living room floors lumber framing flooring

I bought a house last year and I’ve noticed recently a lot of floor bounce in our kitchen and family room. In the kitchen this makes the island shake and you can feel it when a 80lbs dog walks through the rooms. I did notice itwhen we first moved in and I asked about it, but never got a response from the builder.

This occurs mainly on my first floor, but a slight amount does occur on the second, but it’s not that annoying or bad. Both floors use Engineered I-beams that are at least 12” tall, spaced 16” on center. With OSB standard subflooring glued and screwed down. (I have to double check if they were actually glued)

The area it occurs includes the following areas:

Kitchen (18’x12’) - 18’ long I beams with concret foundation at both ends – Unfinished below Family Room (16’x18’) – 18’ long I beams with concrete foundation on one end and steel beam on the other – Unfinished below Dining Room (13’x13’) with concrete foundation on one end with steel beam on the other – Finished below w/1/2” gypsum.

The other areas of the house seem unaffected and have hardwood floors or are areas with less than 12’ lengths of I-joists.

I have read about several solutions and was wondering what would you recommend.

Sistering Joists – Family Room and Kitchen it is possible, but the Kitchen has furnace ductwork and other items in the way.

Running 1”x3” boards perpendicular to the I-joist - Possible in kitchen and family room

Adding another beam - Possible in both kitchen and family room, but would detract from usable space.

Gluing and Screwing in Subflooring perpendicular to I-Joists

Stiffening the underside – Glue and Screw 2×4s along the bottom of the I-beams after raising them up slightly with a jack.

Blocking- Adding blocking to the mid-span area, but this is the least effective method and I’m not sure it will work.

With the Dining Room Finished and the basement finished below it, the only thing that I think will help is adding hardwood flooring since it seams to help in the foyer which has the same span length.

View dennis's profile


90 posts in 5533 days

01-13-2009 06:37 PM

Is this floor above a basement of just the foundation?

-- http://woodsongsfurniture.com

View cpt_hammer's profile


6 posts in 5520 days

01-13-2009 06:56 PM

The entire house minus the garage sits on a basement.

View PaBull's profile


694 posts in 5479 days

01-13-2009 07:10 PM

Hum, Captain Hammer, you did a nice job laying the whole thing out without a picture. You have done a lot of research too.

I think I am with you on the sistering Joists and spend the extra time to remove all obstacles like ducts etc. And I would do the blocking too. Be sure the joists are glued to the sub floor above. The tough part will be to get the support at the ends. This solution will not take away height in the room below.

Good luck and keep us posted.

View Catspaw's profile


35 posts in 5516 days

01-14-2009 02:20 AM

Having built with both standard lumber and I-joists, I find the I-joists to be like walking on the head of a drum. I think standard lumber has a tendancy to absorb the bounce where the I-joists are very ridgid.

Blocking has no effect (I’m equating blocking to bridging which engineering studies have found have no useful effect.)

Honestly my first thought is that the 18’ span is good, but, they will feel bouncy. Sistering will make the biggest difference and is the biggest project. 1×3’s would help but less than skinning the underside with plywood (they would be accomplishing the same thing, except, the ply would have more effect because of continuity.)

A girt (beam) would obviously reduce the span (and bounce) but with the loss of clear space.

-- arborial reconfiguration specialist

View MattFNC's profile


4 posts in 4635 days

09-23-2010 04:51 AM

Great post and responses! I too have had a similar issue, though my builder assured me that movement is acceptable and that any additional support underfloor would be not necessary. Hmm I might try to obtain a second opinion.

Flooring North Chicago

View Generalservices's profile


4 posts in 2601 days

08-09-2016 11:37 AM

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