What Is Causing My 1/2″ Plywood Underlayment To Bubble Up And Ruin My Floor?
In 2002, we added on another bedroom, livingroom, & bathroom to our home near Houston. The house is on blocks above the ground. I installed 2×8 floor joists with support @ 8′ OC, then used chicken wire under the joists to keep the dogs out of the 6″ R-22 fiberglass insulation installed between the joists, vapor barrier towards the floor. I then installed 3/4″ CDX plywood directly to the floor joists. This was my work surface and we caught some rain during the dry-in period. (about 2 months) Then when we were ready, after texture and painting of the drywall, I installed 1/2″ AC plywood over the subfloor to recieve the flooring. We chose an Armstrong peel and stick vinyl tile to lay over this 1/2″ plywood. I prepared all the joints and nail holes w/floor stone. The room is cooled by a central A/C heat pump and has been kept around 70 degrees year round. The 1/2″ subfloor has bubbled up all over. I have repaired some of the places w/screws. I need some help with this.
Virtualrealitys on the right track. I would recommend pulling off the chicken wire and stapling up another vapor barrier to the bottom of the floor joist. A heavy duty plastic roll will work good for this. Then I would put 1/4 inch plywood over that, to seal up the underside of your floor. Go ahead and start over with the underlayment. Pull off the old and make any necessary repairs to the CDX. If excessive moisture has gotten to the CDX it may have started to de-laminate. Also be sure that your CDX is nailed off good. If not use some 2 1/2 inch screws to re-fasten. You can use Luan as your underlayment. Stagger your seams and space your screws at 6 inches on the edges and every eight inches in the middle. Don’t skimp on the screws. If a screw head snaps, be sure to remove it, and be sure that all screw heads are countersunk below the surface. Use some type of leveling compound to fill the nail holes and the seams of the luan. Now you should be all ready for your finish floor. Good luck. Feel free to e-mail me if you have any questions.
did yu put plastic on ground in crawl space??could be moisture working up from crawlspace??if room is cooler than subspace it will condense moisture?
It’s possible that the tiles are pulling it up, or, even more likely, that moisture is seeping between the tiles when the floor is mopped. Either way, you need to relace the underlayment and add a moisture barrier underneath the new floor…
http://www.diychatroom.com
it’s possible that the plywood isn’t WPB,that is moisture resistant. The only options you have are to use loads of ring nails then sceed over with a special screed called feather finish. Other than that, rip it up and start again.
I would recommend removing the sub flooring and starting over. Your problem is because you used nails and not drywall screws to secure the flooring. Over time the walking on the floor loosens the nails allowing for moisture accumulate under the sub floor. I recommend using 1/4″ leuon with a drywall screw that is not too coarse (has many threads) secure the leuon to the flooring then use self-leveling Portland cement underlayment to fill all the screw holes and the joints between the the leuon. This should leave a perfect surface that will last for many many years. You can lay peel and stick tile on this and not need any additional adhesive glue.
I do NOT recommend using nails for any flooring applications as they can work loose over time.