There are a variety of approaches that can be taken for installing hardwood over top of a concrete slab, but before you begin any installation you must test for moisture. You can test for moisture using a rubber mat test, a calcium chloride test, a phenolphthalein Test, or a Polyethylene Film Test. After you have completed these tests, you will be in a position to consider your installation options, including a plywood on slab method or a screen method. To learn more about installing hardwood flooring above a concrete slab click here.