We have a new construction home 7 months old. In the past 3-4 months I have noticed a bounce in every room of the house. The TV rattles in the entertainment center and the dishes on the table rattle when walking in the kitchen. Same thing in our master bedroom, everything rattles when walking across floor. We have engineered I joists 12 in spaced 16 in apart. The span the I joists cover is 21 feet. Is this normal? We also have one joist splitting and our builder won't come look at this problem. If builder isn't responsible, how do we fix it?

Your builder is responsible for this repair but appears to just be a pain. Call your county building inspector and ask if your home past their inspection prior to occupancy. Tell him about the problem you are having and if he knows your builder.

If that house is seven Months old then it should be under warranty.. What's the Contract say?
Is there 3/4" toung and grove for sub floor?

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Your builder is responsible for this repair but appears to just be a pain. Call your county building inspector and ask if your home past their inspection prior to occupancy. Tell him about the problem you are having and if he knows your builder.

I agree. In my area a CofO (certificate of occupancy) is issued after all inspections have been made and approved.

Chuck

If the joists are 16" apart, cord edge to chord edge, you have 19.2" oc which is not uncommon for engineered products and it will feel bouncier than 16" oc as measured from plywood to plywood. A few other things you can check, though, underneath any wall that crosses the joists, there should be 2x material inserted along each side of the plywood, supporting the top/bottom chords. Also, if the bottom chord anywhere was notched for plumbing, you actually have an unsupported joist.

At a last option, contact the manufacturer of the beams. There should be markings on them. It's possible they were also slightly undersized...for example, if they are at 19.2" oc, they may have only been rated for that span at 16" oc. Might not be a bad idea anyway, just for your own knowledge.

There is no excuse, though, that the builder has not come back out. As suggested, the building department in your town is a good way to light a fire under his arse. Often they'll see bad or wrong work and reuse to issue new permits or refuse to inspect work in progress until the complaintants issues are corrected. They respond much differently to structural issues than cosmetic issues so you could make some good progress.

I agree, when talking to the inspector tell him more about the cracked joist than the bounce. All floors have some bounce so that could be viewed as subjective. You should not have a cracked joist, period.