We just finished installing new windows in our house that was built in 1968. Ever since then, I have noticed what appear to be higher humidity levels on the bottom floor. It is concrete but most of it is above ground, but not all of it. I am wondering, now that we have new windows, is it perhaps keeping in more moisture than before creating more humidity? We have laminate flooring over the concrete and it has not been sealed because we never noticed a mositure problem. Is it possible that the unsealed concrete is creating this problem and is sealing it the right thing to do? I have concerns because Ive read in other places that sealing concrete can cause moisture build-up and in turn cause foundation settling....any information you can offer is much apprec iated. Our home would be extremely hard to retro-fit for an air exchange system.
Sandra ~ Anchorage, Alaska
Sandra, in most cases, high humidity levels in a home are caused by activities within the house, such as using hot showers, cooking, or operating the dishwasher. Most homes have exhaust fans to help get that extra moisture out of the house, but tell-tale signs such as water on the inside of windows or mold growth can indicate that too much moisture still remains inside the home. These tell-tale signs are often more obvious in newer homes which are better sealed and insulated, because the moisture is unable to escape through drafty windows and doors. In fact, most new homes are so air tight that air exchangers, mechanical vents, or heat recovery ventilators are necessary to keep humidity levels down and to bring fresh air inside the home.
In your case, the new windows which have been installed in your home may have made your home more air-tight, which in turn is causing the moisture levels in your house to be more noticeable. Before I would go through the trouble of tearing up your laminate floors to seal your concrete slab, I would make sure that you have operable exhaust fans in all of your bathrooms and kitchen to help rid your house of any unwanted moisture. You could also try using a portable dehumidifier on your lower level and see if this has some positive results.