We are building a detached shop building, and do not have the permanent heating system installed yet. The exterior siding is on, and the interior walls have been insulated. The roof trusses are still open. We recently began heating with a kerosene heater, with windows open and several large box fans to circulate the air. There is a noticeable amount of moisture behind the insulation, but we are hearing that it is OK to sheetrock now even though the walls have moisture. I believe that this moisture will dry out in time, but much more slowly if we put up the sheetrock. To speed it up we would need to pull out the insulation to expose the wall surfaces.

My question: is it OK to close up with sheetrock with damp walls behind the insulation?

Absolutely not! Who's idea was it to insulate the walls before the roof was on? First, you frame your wall and roof then you sheet the walls and roof, next step is to black paper the roof. This is called (dried in) after it is dried in you can do the exterior siding, now it is to late for that but next time you'll now. As far as your situation goes if your insulation has been rained on and is damp, throw it out and buy new insulation, this is not an opition here, its got to go. The walls will dry out quickly but the insulation will not and will cause moisture and mold problems later. The walls are maybe r 13 or so and though it will cost some money to replace its better to do it now then when you sheetrock and then have to tear it all back out later to do what you need to do now. Good luck

Gad you are asking for trouble. Rip out every inch of insulation and get that roof done next. Glavine and I could come down and do it for you but we are having fun here.

Oh, sorry my post was not clear. We have a roof! The building was framed, sheathed and roofed by last October, and the siding is on. When I said the trusses are open I meant there is no insulation in the attic. The roof is architectural grade composite over heavy paper, and there are no leaks. There is great ventilation in the attic with bird blocks between every truss, and the plan is to blow in insulation after the ceiling drywall is done. The only insulation already done is batts of R21 in my 2x6 wall construction. This was put in during a fairly cold spell with 28-35 degree lows and several inches of snowfall. All of the moisture in the walls is apparently due to condensation from cold weather (35-40 degrees at night) and heating the inside. There is also a full concrete slab floor, about 1100 sq. ft. and that probably contributes humidity to the room as it cures.

We have been running a 175K BTU kerosene heater on a moderate temperature setting, maybe 60 degrees, continuously for a week, and there are still many wet spots behind the insulation. None of the insulation itself is saturated with water, but the back side against the wall is wet on the surface.

Today I discovered that the insulation crew did not do the insulation batts correctly where there are wires - instead of splitting the insulation and slipping half behind and the other half in front of crossing wires, they just compressed it over the wires.

I am tempted to set my schedule back a week or two, pull down all the insulation and spend another 300 bucks on kerosene to get the walls dry. However, if this is overkill I'd like to know. I'm not sure I can get the insulation installers to put it all back without paying more, but I do want it done right.

Not overkill, you likely already have some mildew growing on the interior wall. It must be totally dry. The installer may replace some of the insulation if you can show they did not follow code. Splitting the insulation is a smart way but may not constitute a code violation.

No no no, do not close up the walls with there being moisture in the walls.

OK, OK - I won't! I pulled down all the insulation today, and was glad I did. Some of it was wet enough to splash my face as it came down. All the water is right on the surface of the wood and the insulation. It appears to be condensation, not water weeping out of the wood itself. I think that with three fans and a big heater running it will dry out the wood in no time, and the insulation even faster (!? ). Thanks for the advice!