Resilient flooring is durable, but from time to time minor repairs must be addressed. Air pockets are caused by the adhesive no longer working. This is common as floors age, and the resulting bubble is fairly easy to deflate and rebond to the subfloor. 
If not attended to, the area will eventually harden, split, and crack-making the problem more noticeable and difficult to fix. Even a curled edge on an otherwise healthy vinyl tile can be easily glued back into place. If the repair doesn’t hold, the entire tile must be replaced.
HOW TO FIX A BUBBLE
Step1: Deflate air pocket. Use a utility knife to lightly score and then slice through the bulge. This allows air to escape. Extend the cut a little (1/2 ” ) beyond the blister at both ends. If possible. cut along a line in the pattern to hide the cut.
Step2: Choose an appropriately sized tool to force fresh vinyl adhesive through the slit and under the bubble. Press the edges together. Wipe up any excess adhesive with a damp cloth. Cover the patch with wax paper and some books while the adhesive dries.
HOW TO FIX A CURL
Step1: If the corner or edge of vinyl tile is curling. but the rest of the tile is in good shape. you can refasten it. Use an electric heat gun to warm the area. This makes the vinyl easier to work with and it softens the underlying adhesive.
Step2: Use a flexible tool (such as a small putty knife) to lift the tile just enough to spread the underside with fresh adhesive. Wipe up excess glue with a damp cloth or sponge.
