Fastening SurePly® Premium Plywood Underlayment
- Do not use any adhesive on the sub-floor beneath SurePly® plywood underlayment.
- We recommend a pneumatic fastener tool that incorporates an adjustable depth-drive control to prevent fastener “blowthrough” or “over-driving.” If this feature is not available, adjust the air pressure on the compressor to an appropriate level to avoid fastener “over-driving” or “blow-through.”
- Choose either double coated chisel point staples with a 1/4″ maximum crown or coated ring shank underlayment nails with a 3/16″ diameter head. The length of the selected fastener should be a minimum of 5/8″ but not so long that it penetrates through the bottom side of the subfloor. Do not select a fastener that is uncoated, cement or rosin coated, as they may rust and discolor your floor.
- Stand on each plywood underlayment panel during fastening to ensure full contact with the sub-floor. Any “crackling” or “popping” noises indicate debris is underneath the panel. Should this occur, stop the installation, remove and discard the panel, then scrape, sweep and vacuum the sub-floor again until all debris is removed.
- All fasteners should be countersunk slightly below the surface of the new underlayment.
Using Seam Filler with SurePly® Premium Plywood Underlayment
- If you choose to install the SurePly® plywood underlayment panel with an expansion joint you must use a seam filler.* Check with your flooring supplier/manufacturer to be certain your seam filler is acceptable.
- Do not “floor-mix” seam fillers on top of the SurePly® plywood underlayment panel face. Mix the seam filler separately in a bucket.
- Once the plywood underlayment panels are fastened, apply the seam filler and allow it to dry completely in accordance with the manufacturer’s instructions. Allow sufficient curing time to completely dry the seam filler.
- Sand all joints with a belt or floor sander until level and smooth. Hand sanding is not sufficient.
- Do not oversand or “cup” the joints. Some additional application, drying time and sanding may be necessary to smooth high or low spots.
- After sanding, the seam filler should fill the seams and be flush with the edges of the SurePly® plywood underlayment panels. We do not accept “feathering” as a substitute for sanding the seam filler.
- Thoroughly vacuum the entire area to remove all debris before installing the floor covering.
* Note: You may leave an expansion joint without seam filler when SurePly® plywood underlayment is used under carpet, engineered floors, or wood floors.
*Notes on Telegraphing Seams
Telegraphing of seams is a result of incorrect installation and/or insufficient acclimation of the underlayment. The acclimation requirement exists with all forms of underlayment and is a CRITICAL part of any installation. Without acclimation a panel can expand up to 1/4″ in the panels length and width. Most seam problems occur because the panels are not acclimated and installed cold with no expansion joint. When the panels reach room temperature, they expand and arc up at the edges as the seams are pushed together. There are many other factors that can affect the potential for telegraphing seams such as the subfloor, vapor barriers, humidity, moisture content, and seam filler preparation. Nothing short of physical plywood failure such as a delamination will be warranted with regard to telegraphing seams.
Caution Regarding Point Overloading
After installation, care should be taken to avoid “point overloading” of the finished floor. When moving or positioning any heavy object across the floor (such as a large appliance), place a minimum of 1/2″ plywood on top of the completed floor to prevent point overloading.