# Need guidance on subfloor problems in new home.



## wb1026 (Jul 4, 2006)

Hi all!

We bought a market home last summer (been in 13 months now) and the builder just cannot seem to resolve problems with the subfloor on the main and second levels. 

The joists (dimensional lumber) seem to run every 16" (basement is unfinished so I can access the joists for the main level) and the subfloor is 19/32" (osb I believe). Interestingly, where there is hardwood (kitchen) or tile (bathrooms) the floors are fine. I have dealt with problems in just about every carpeted area, however.

1). When I walk from the kitchen into the family room and step off of hardwood and onto carpeting (walking perpendicular to joist run), there is a lot of noise that can be heard from the basement. I fixed some of this by loosening the clamps holding the water line to the joists. I discovered that with the pipes clamped so tight, the water line was actually creaking as your walked across the floor. Now I have noise in the main trunk of the HVAC that runs perpendicular to the joists, in this same area. 

2) In 2 downstairs rooms, if I walk perpendicular to the joists, the ductwork makes an oilcanning sound--even though the ductwork doesn't come into contact with any joists. The register box is nailed into the subfloor.

3) On the 2nd level, I have creaking in 2 bedrooms. The builder pealed back the carpet and isolated the noise to subfloor joints. They minimized the noise in 1 room and it has not abated in the other.

4) In my upstairs hallway, there is an oilcanning sound that has gotten worse with each attempted repair of the subfloor in an adjacent bedroom. It seems that the subfloor and HVAC ductwork like making music together up there. The floor is springy and creaks within a 4-foot line (recatangle) of where the ductwork comes up to the 2nd floor. Builder repairs of the cold air return have made the whole problem worse. Interestingly, some times, when I climb the stairs to the 2nd floor and step over this area, I get the oil canning of the ductwork and a popping like sound from the base of the wall that separated the hallway from the master bath. I had made the comment to the builder that I can be getting out of the shower and know when someone was coming down the hall because of that popping noise. To me, it has seemed like the doward pressure of a step in the hallway puts upward pressure on the sill plate or the subfloor in the bathroom (which has tile and a thicker subfloor on it).

I have read some articles about adding support to joists in this type of problem and I have tried that where I could--and it did not help.

I just walked through a new home in my neighborhood that is in the framing stage (higher-end builder) and noticed that their floors were much more substantial and also quieter. The builder that built my house has had this type of problem in both of their models they built here, our home, 2 neighbors homes, and another market home.

Could all of this be related to the thickness of the subfloor? I really want to upgrade the carpet in my home but will wait till I get the creaks and other noises fixed. If I should add to the existing floor, how much additional thickness? Do I run it parallel or perpendicular to the existing subfloor?

Thank you for your help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


I've tried bracing the joists that I can access from the basement with 2x4s but I still have areas that I would describe as "springy". In this same area--when I step off of the hardwood and onto the carpeted area, the main trunk (I think its the cold air return) of HVAC makes an "oil-canning" sound. In 2 rooms, there is noise related to the ductwork (baffles me) that runs parallel to the joists. The one


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## Bonus (Aug 25, 2005)

This sounds like quite the issue, and I'm not sure I can help, but anyone who might be able to is going to want to know the size of the joists and their span. Also, were they blocked or braced in any way between supports? 19/32 is the bare minimum for sub-floor, but if the joists are not over-spanned it should do. Don't let your builder off the hook, it's HIS problem.


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## wb1026 (Jul 4, 2006)

*joist info*

I just went down into the basement and measured the joists. I assume they are 2x10's (they are just slightly smaller than that) and run from front to back of the house. They run roughly 14 feet before resting on a metal beam that runs perpendicular (with a board on top of it). Another series of joists are nailed to these and run toward the rear of the house. There are a series of 'X' s (1x2s?) that run in a line approximately half way thought he span. 

I was just up in my son's bedroom and was standing in front of the cold air return (the vent is about 5 feet up the wall) but at a point in the room that was about 3 feet from the wall. Standing with my feet parallel to the run of th joists, I was able to hear a crinkling sound of the metal ductwork by rocking back and forth.

Any guidance is very much appreciated. I agree with you that its the builder's repsonsibility to fix this but I need some knoweldge to counter their argument "well you're goign to have 'some' noise, which is normal."

Any ideas on the subfloor thickness in relation to the joists (asdescribeabove)???


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## KUIPORNG (Jan 11, 2006)

What I am going to say you may not want to hear. I bought a new house 2 years ago, I spend over two thousands on upgrade to change the OSB board to pine wood board. Noise level is excellant, don't hear anything in the whole house. I think one main reason of the problem is the instablility of the OSB board. I don't think there is a solution for this. You may be able to reduce the noise somehow by putting nails here or there, but over time and constant stress. this will come back. and I think it is normal to hear noise here or there with OSB board subflooring, this situation will also increase its magnitude over time... To some people, this may be unbearable, but to some this can be considered normal situation...


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## wb1026 (Jul 4, 2006)

granted I know this is not going to be an easy fix but my question is...why do I not have any problems with floors that have an additional underlayment? For example, in the master bath, if I pull up the register cover, I can see the tile, some sort of backer-board material, and then the subfloor. In my kitchen and hallway downstairs, I have hardwood that runs perpendicular to the joists, a paper material and the subfloor. Its when I venture off of these areas that I encounter creaking in the floor or ductwork that makes an oilcanning sound when I walk over the adjacent subfloor. 

Would not an additional layer of some sort add rigidity to the floors?


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## manhattan42 (Jun 4, 2006)

OSB has nothing to do with this, and the nail holding and sheer strength of OSB is often greater than dimensional lumber.

Part of the problem may simply be in faulty nailing. Not having glued the subfloor or nailing at less than recommended intervals can cause these problems.

More probable is the fact that 19/32" OSB meets minimum code for 16" spans, but it does so barely and few reputable builders would use anything less than 3/4" ply or 23/32 OSB for 16" on center spans.

This 'thin' subfloor would also account for why your reinforced floors feel sturdier. The fact that more nails fasteners would have been added with cement board and hardwood flooring could have stabilized a subfloor that did not have enough or the right kind of fasteners.

Short of pulling up the carpeting to allow you you re-nail the floors form above, or placing blocking between the joists to better support the OSB, there isn't much else you can do.


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## Bonus (Aug 25, 2005)

I would agree with Manhattan, this is not related to the subfloor material, but it's thickness and fastening. Sounds like you have bracing and adequate depth for the span (just). IMO it is not normal to hear the ductwork 'crinkling' when walking across a floor.


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## wb1026 (Jul 4, 2006)

*subfloor thickness*

It figures...this builder cut so many corners in this house. Its a shame, its a really nice house but just some things that drive me nuts! 

I do plan on replacing all of the carpeting which is why I've been asking about how to fix the subfloor. How thick should I go on the subfloor?

I have yet another appointment with the builder tomorrow to have them fix the crinkling ductwork in my upstairs hallway--so I will mention to them them that I have been asking for advice on how to fix this problem--since its evident in just about every room.


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## kawendtco (Oct 5, 2007)

i would suggest adding 3/8 or 1/2 plywood running same direction as existing floor only staggered 1/2 the sheet so as to tighten the floor up. subfloor adhesive over entire area as you place sheathing and screw every 6" each direction. the glue will help to create a multi layered subfloor and will add to its rigidity similar to the lamination of cement board floor in the tiled area such as your bathroom.


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## Stevoph (Oct 6, 2009)

*subfloor*

I agree with the lastest suggestion of adding the entire floor with 1/2 CDX ply would do the job AND this would be good for future hardwood flooring. CDX ply hold the nails better than OSB. Have you ever tried to take out a bad strip of oak from CDX or OSB? I have.... pull out real easy with OSB and it is tough with CDX ply.
Stevo


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