My close friend recently finished building a new house with hydronic heat. The house is properly insulated and the heating system works perfectly. The basement (which is only about 1/3 enclosed) is as yet unfinished, making it possible to look behind the insulation (both r-13 and r-19). When it's cold outside these walls are all wet. So much so that it runs onto the bottom stud and plate. In areas where there is no insulation whatever, the walls are completely dry. The house was built with a very tight house wrap to block wind. So what is causing the wet walls (osb)? The upper floor may be the same but as the walls are finished we haven't yet open one up to check their condition. Could the hydronic heat be part of the problem? The basement loop was put in 6" of concrete. The upper story hung from the 1st floor. Any ideas? All replies will be appreciated.