When there is water coming in from under the concrete slab, it is usually due to a high water table underground. Often, during the rainy season in certain parts of the country, the water table rises considerably, causing hydrostatic pressure to build under the concrete slab, especially in a sunken or low lying room. Cement is ultimatley pourous, and with surface cracks and seams at the joints, the water will follow the path of least resistance and come into the home at that point. Unfortunately, the water sealant between the carpet and floor will NOT work...you have to look at the source of the problem. Look around your house after a good rain and see if there is any standing water next to the foundation. If so, you need to find a way to drain the water away from the house...gutters are a good idea, but you have to keep them clean and install downspouts to drain the water away from the foundation. Look at the grading of your property...does the land slope toward the house? Check the ground after a rain and see how long the earth remains saturated with water..these are the areas that need drainage attention. There are solutions such as a sump pump or french drain, but most of the problem can usually be solved with a little investigation into how the water is draining away from the foundation. Good luck!