Hello 2blackdogs and thank you for your question.
The Pergo flooring is designed to be installed as a ﬂoating ﬂoor. Since it will expand and contract with temperature and humidity changes, it is essential that a 3⁄8" expansion space beleft around the ﬂoor’s perimeter. Flooring that is glued into place will not be able to expand and contract, thereby allowing it to warp or buckle.
A stair application is the ONLY time that a Pergo floor is glued directly to a substrate.
There is additional information available in the Pergo Installation Essentials Guide For Laminate Flooring located here: http://www.homedepot.com/catalog/pd...
Best wishes on your project.