If you don't want your wood-veneered project to warp, then chances are you will need wood veneer backer sheets. They are also called balance backer sheets. Veneering both the front and back of each wood veneered panel will prevent warping.
Warping can occur because of the curing process -- when your veneer sets in place with whatever adhesive you've chosen. Even after all is set and done, months later, seasonal changes in humidity may also cause warping.
What kind of backer to choose?
It all depends on whether the "backer" will be visible. Is it backing a cabinet door that will be seen each time the door is opened? If so, you probably want to stick with the same quality of veneer you've chosen for the front of your project.
If your backer is really in the back -- and never seen -- it is safe and more economical to go with the least expensive grade of wood veneer backer or "Plastiback" backer sheets.
The economy grade wood backers are perfectly fine wood veneers that will have some type of grain anomalies and are perfect for secondary surfaces. They will maintain the good looks of your project, however, by creating an even and stable bond with the wood. The backer sheet should be applied at same time as the face veneer for best results.
Our currently most popular ready-to-ship in-stock flexible wood veneers: