Hey everyone,

I have an issue on my latest project that baffles me., I can really use your collective thoughts and recommendations  on this.

One room in the house, the bedroom is 14 x 13 with ridge beam at center and 12 ft high. The floor is concrete with hydroponic water, heating the slab. thermostat is set at 68. The finish on the ceiling is 1×6 t&g fir directly nailed to the bottom of the rafters. Cathedral style.  Between the joists (2×6) is 5″ thick rigid insulation. The rafters are covered with 5/8″ plywood and on top of that is “Tyvek Roof Liner,  premium roofing underlayment”. The finish roof surface is standing metal roof and the color is dark bronze. The metal roof has been on for at least six months. We have been through many bad rain storms here in California and not a leek in the place. Last Tuesday I get a call from the client his ridge beam is wet in the bedroom he noticed it at approximately 2:30 in the afternoon. it has never appeared before.  I head over yep, about 2 to 3 inches down from the ceiling is moist and is the length of the beam except about the last  3 feet at the north end is dry. the following morning I return to see that it is now dry. I do a short investigation, remove vent cap to notice no moisture entering from the exterior. the client arrives haome later that same day and texts me, ‘It’s staring to get wet up there again, damn.” I reviewed the pictures taken of the project and no water lines are in the vicinity of the beam. There are no roof penetrations. I have posted a video I’ve taken showing what I have done to investigate , but I’m a carpenter and not a film editor so it is not of the best quality but should give hopefully enough information for a possible solution. The video may be viewed here.

http://mox90291.smugmug.com/Construction/construction/9991220_EdCdW#1188065669_U4mx7

The video is to help you with your thoughts and recommendations . After ruling out that no water is entering from  the roof,  there is no water pipe leaking inside the ceiling cavity. and remember that 3feet of dry beam at the north well there’s a roof from the other part of the house over that area of the bedroom roof.  The only possibility I can come up with is atmospheric, the moisture in the ceiling cavity is condensation caused by a closed ceiling cavity. the architect did not specify any ventilation, ridge vent, in addition to lower vents at the bottom of rafters, possibly, as it would deter from the clean architectural look she was after.  So now for corrective measures, a ridge vent running the entire length of the ridge is doable. Do I need to have vents at the bottom of the rafters to create a flow of air or does the heat accumulating and rising, exit the roof vent on it’s own .

 Thanks in advance, Mox