×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Nail Popping At Plywood Underlayment

Nail Popping At Plywood Underlayment

Nail Popping At Plywood Underlayment

(OP)
A restaurant we designed about a year ago is experiencing a problem.  The 5/8" thick plywood underlayment was nailed to the 5/8" plywood floor sheathing with 8d "ringshank" nails at 12" oc.  At the bar area, where ceramic tile occurs over the underlayment, nails are backing out of the underlayment and causing bulges in the ceramic tile.

What is causing this?  Some ceramic tile was removed, and no evidence of moisture damage was found in the plywood.  The contractor thinks it is being caused by patrons jumping in and out of bar stools, causing the floor to bounce.  But we did use TJI floor joists.

RE: Nail Popping At Plywood Underlayment

Never had much faith in ringshank nails, I'm not a contractor but I've always made sure that nails for that application were actually screws, hope someone else has a better answer...Mike

RE: Nail Popping At Plywood Underlayment

Dave,
I agree with Mike that ring shanks don't always work well.  I suspect you are having a combination of issues, the most prominent being wet-dry cycling of the plywood from the cleaning process.  This occurs without the presence of explicit moisture damage showing in the plywood.  It is a result of very small volumetric changes in the plywood, but they lift the head of the nail initially, then a similar process works on the shank.  This is a non-recoverable action in that the nails go up, but they don't go back down, 'cause there's no action to cause them to do so!  This results in the nails backing out.

While the bouncing might contribute after a while, it is not likely a big part of the problem.

Solution is to use corrosion resistant screws, spaced at about 6 to 8 inches at every support.

RE: Nail Popping At Plywood Underlayment

American Plywood Assn approved construction adhesive between the joists and plywood would have been a good preventative measure in original construction.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources