FHB Breaktime community,
I’m looking for some help on “noodling” a perplexing issue with a recent 2nd story addition that I added to my home in sunny Denver Colorado. The short version is that in certain areas of the new 2nd story when I walk on the floor it “crackles” very significantly – but then stops and won’t repeat for a while. Detailed story below.
The new 2nd story was added to an existing brick (2-wythe) and wood frame house. There was an original brick home (about 110 years old) with a substantial stick-frame addition to the side and back in the 1980’s (I say substantial as it is a post-and-beam structure that used 2×8’s and 2×10’s built-up for the posts and beams; it’s a built like a bomb shelter!). The foundation under the brick portion was just that – brick; the foundation under the stick-frame addition was a 24″ x 48″ continuous footer. I had two engineers sign-off that the existing 1-story house could easily handle a new 2nd floor.
The new 2nd story is typical new construction – 2×6 exterior walls, 1/2″ sheathing; 3/4″ plywood t&g flooring over TJI’s; truss roof. Exterior is hard-coat stucco, with double-layer paper, wire mesh, scratch coat and finish coat. Interior finish is typical 1/2″ drywall; floors are covered in carpet or tile for bathrooms. No hardwood.
One interesting point is that over the old stick framed first floor there is a 12″ void between the new 2nd story floor joists and the top of the old 1st floor roof. More specifically if you were looking at a cross-section you’d see the first floor ceiling joists, a layer of 3/4″ plywood, a 12″ void, and then the new 2nd floor joists, then the new 3/4″ sub-floor, etc. This void did not happen over the old brick portion of the house as it was higher than the stick-frame portion.
The new 2nd floor sub-floor was installed with ring-shank nails and liquid-nail adhesive.
Here’s the phenomenon: on hot days when i walk on the 2nd floor areas that have the 12″ void underneath there’s a significant “crackling” noise that sounds like the floor is going to cave in. Once i walk on the floor and get it to make the noise it won’t do it again for a long time (12-24hrs). On cooler days it doesn’t happen as loudly, but it still happens somewhat.
Note that there are absolutely no cracks anywhere on the interior walls either on the 2nd or first floors. This crackling does not happen when i walk on the 2nd floor areas with no void underneath.
So what is happening? is it a thermal issue? is heat “collecting” in the void and reaking havoc on my subfloor, causing it to expand and contract on hot days? Is it somehow related to the ring-shank nails or adhesive that was used? Any help is appreciated.
Denver8
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SamT
Any flush framing? Beams with hangers? Joists in hangers make alot of noise sometimes.
I do know that Liquid nails is not my top choice for subfloor glue. I had a winder box squeek when I used it. The ones I did with OSI and PL never made a noise.
Were the mechanicals run throught the 12" void between ceiling joists and floor joists? Any possibility of heat ducts or plumbing vents hung from the joists?
Did the subs cut any joists to pieces when installing plumbing or heating?
Matt
Not sure what "flush framing" is. No beams with hangers but the joists are hung on the beam (which sets on top of the old brick walls) with hangers. The duct work is from above via the ceiling but the plumer did cut through a bit of the joists for the drains and water lines. I inspected and they looked pretty good -- in the center of the joists. Nothing hung from the joists, just going through. most of the problem starts away from any mechanicals anyway, so i don't think it's that.
Flush framing to me means beams with hangers. Joist flush with a beam not sitting on top of one.
Typically if its a subfloor noise it's a squeek, where the subfloor rubbing against the nails makes the noise.
You describe it as a "crackling" noise. How big of an area makes this noise? Is it near the outside wall where the beam sits? Almost sounds like beam rubbing on bricks to me, if it indeed a crackling noise and not a squeek.
I would pull the carpet and investigate, if it's a squeek screw the floor down with deck screws (not drywall screws). I have seen the OSB in a I-joist split the bottom flange when a point load was too large, this might be another cause for a crackling noise.
Matt
the noise is near the entry to the room, which is about 12' from any exterior wall. it happens throughout the room, but begins in one specific area. since it doens't do it again for a while after the floor is walked on i'm inclined to believe that it's not a board / beam moving on brick. i'll take the carpet up and screw the subfloor down a bit better and go from there. appreciate the help.
Matt
Liquid Nails is not a structural construction adhesive, just a panel and trim adhesive.
So if any of the conditins were less than perfect - like dust or moisture on surfaces or wet framing lumber that shrank, that is the cause of your problem.
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So do you think that if i lifted the carpet and screwed down the subfloor (in addition to the ring shank nails already there) that that would help? if there is liquid nails on the hangers then obviously my solution won't be effective on that portion, but i figured it may help if it's between the subfloor and joist.
yes
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RANT #4769BLiquid nails is not a PRODUCT.It is a BRAND NAME.If the product is Liquid Nails Subfloors & Construction Adhesive then I would assume that it is for subfloors.http://www.liquidnails.com/ViewProductDetails.do?productId=44
http://www.liquidnails.com/ViewProductDetails.do?productId=45However, if it was Liquid Nails Foamboard & Projects Adhesive then I would not think that it should be used for subfloors.http://www.liquidnails.com/ViewProductDetails.do?productId=34Likewise with dozens of other Liquid Nails products.http://www.liquidnails.com/ViewProductListing.do.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Edited 9/29/2007 2:03 pm by BillHartmann
Point taken. I have not used it for twenty some years since back when it was a ont lable product, and an inferior one at that.
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But how about that cowgirl chick in the ads?
Forrest
she must be getting pretty long in the tooth by now...LOL
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Forrest
Edited 9/29/2007 9:11 pm by McDesign