wall studs moisture.

[kevfish1]

I have a spray foamed fish house with 2x2 walls, aluminum siding and paneling on the inside. Forced air furnace. My walls are wet where each of the wall studs are at. Why is it doing this??? Never seen this happen before with wood studs. Metal studs yes but not wood. How can i cure this?????

[Bullwinkled]

I copied this from a transcript:

Metal substitutes of the wood structure are very often being installed without consideration of the difference in thermal conductivity between wood and metal. Strong thermal bridges caused by highly conductive metal components worsen thermal performance of these walls. In metal stud walls, the reduction of the in-cavity R-value can reach 50%. Because steel has higher thermal conductivity than wood and intense heat transfer occurs through the metal wall components, thermal performances of a metal stud wall are significantly lower than for similar wood stud walls. A reduction of the in-cavity R-value caused by the wood studs is about 10% in wood stud walls. That is why metal stud walls are believed to be considerably less thermally effective than similar made of wood.

[kevfish1]

The issue is that the paneling is wet where the wood studs are

[Bullwinkled]

Sorry, I totally misread. Although in this kind of weather the R value of 2 inch wood vs 2 inch foam would be considerable and (heat) cold transfer would be noticable. the only way around it would be to insulate at the stud points, not practical in many cases.

[kevfish1]

That is what i was thinking. The stud remains cold and thus when the heat hits it you get condensation? I just did not think a wood stud would do that??

[Bulldoggr]

did you vapor barrier the wall? I would have vapor barrier the interior side of the wall. Even if i used spray foam. Then put the paneling on.

Just my two cents.

[kevfish1]

no vapor barrier

[late night]

I have a similar problem. I am building a 6x8 perm and when I turn on the heat I have little moisture spots around every screw head in the walls and ceiling and I did poly the inside. I think its the screw itself drawing in cold air from outside and condensating on the inside. I hope its not enough moisture to damage my interior paneling. But, what do you do?

[minneman]

no vapor barrier

wouldnt matter, the moisture is on the inside of the house anyway, and the cold stud is holding it there on the inside of the shack/paneling (condesation). it is probably getting to your insulation however, but if closed cell it shouldnt matter, either way the paneling may be in tough shape in a couple years. could try venting more?

[kevfish1]

I am thinking of popping the pannelling off in da spring and putting some 3/8th inch styrafoam behind the panneling. would that take care of it???

[Christopher Quast]

Do you have an outside vapor barrier? My house does but no inside one and I will have cold spots sometimes when the weather is really brutal, but as soon as it warms a little I no longer have this problem, but you said every stud shows.

Hmmmm??? What was your exterior again, mine is polebarn siding? I am still thinking interior vapor barrier would do the trick minus a few screws drawing in frost. Good Luck

[chickeywing]

How serious do you want to get? Poly would be better than 3/8 foam. You could try adding furring horizontally to the studs. Hang poly and attach the panneling to the furring. minneman may have the answer: venting. What type of heater do you use? When propane burns, it releases huge amounts of moisture. It is a major problem with construction in the winter.

TC