Should I leave a gap when using any trimming product? A Should I leave a gap when using any trimming product? When using any of our featured trimming products, you should leave an inch (1″) after inserting mats into the trim. This will allow mats to “float” or expand and contract within the trim during seasonal temperature changes. Share facebook twitter linkedin pinterest email Back to Top What floor preparation is needed other than cleaning? Are there tools or any other materials, i.e. adhesive, trimming, seaming or other sundries needed to join mats or finish edges? Can G‑Floor roll out flooring be used outdoors?