We recently refinished a family room that was originally a garage. Put in new wallboard, insulation and new laminate floor over ply wood. Now have a horrible odor of mildew that is very strong. Any ideas what could be causing this odor and solution.

The original garage floor very possibly did not have a vapor retarder under it. How old is the house? The odor is possibly caused by moisture migrating up through the concrete slab, and causing mold in the wood framing for the new floor, and possibly in the backing of the new floor also.

You are not going to want to hear about the cure, if that is the cause.

You will need to remove the floor and subfloor, and get rid of what mold there might be, and then place a vapor retarder (such as 6-mil polyethylene sheet) over the concrete floor, lapping all joints 6 inches and taping them.

There will still be a problem at the intersections with the walls, getting the vapor retarder under the sole plates. It will be very difficult to retrofit the vapor retarder and do it properly.

Sorry.