moisture/condensation issue

[yanmars]

I have a lean to on my building. Decided to enclose it. Poured a concrete floor. Block on top and then stud walls covered with 3/4 inch plywood and some 3/4 OSB. Covered with house wrap by Carter Lumber Co called R Mor. Top and bottom edge now sealed with brand name sealant tape. The outside walls are under the overhang of 12 inches with a 5 inch D spouting with underground drain tile connected to transfer the water 50 feet away. All building has gravel 10 feet or more around the concrete.
Under the house wrap I am getting moisture/condensation. As high as the roof in places and down. Roof is 5 year old metal, 2.5 or 3/12 slope and no leaks there.
Unsure where the moisture is coming from and do not want it to eventually damage the sheeting. Thoughts?

 

[RjCorazza]

I am currently planning a pole barn over an existing 6" concrete slab. I have been warned that since I didn't put a vapor barrier down over the gravel base, that I will have moisture coming through the slab.
Hopefully an epoxy coating on the concrete will be sufficient, but I am still investigating....

 

[yanmars]

I did put a heavy moisture covering( rubberized or vinyl roofing material) over 2 inches of EPS foam under the concrete. Gravel under all that and the concrete also had a sealer put into the mix. I do not see the moisture inside the lean to, I have not yet installed the two 36 inch entrance doors. Moisture only between the housewrap and plywood.

 

[newbury]

I bought a 40x60 shed with metal roof in Mississippi that rusted out. The roof was very little slope. Before I replaced it in spring & summer it would rain inside from moist air condensing inside on the metal roof. Replaced it with a roof with more slope and 1/4" insulation inside.
Problem solved.
Your moisture may be coming from ambient air.

 

[oldnslo]

I had to add ventilation louvers On my dirt floor pole shed to keep it from raining inside on humid days. Like Newbury I suspect moisture is from ambient air - condensation.

 

[EddieWalker]

In order for condensation to form, there has to be an air gap. Condensation is caused by the temperature of the air changing to the point it cannot hold the water vapor in the air. This normally happens in the early hours of the day when the air is the coldest, and just before it warms up. Warm air holds more water vapor then cold air.

If your house wrap is tight against your sheathing, then it's impossible for condensation to form in-between there.

If the bottom of your metal roofing is exposed, then it's very common for water to form under the metal. Since the metal is sloping down to your wall, it's probably allowing the water to transfer from the underside of your metal roof, to the top of your wall, and then work it's way down the wall, under the house wrap.

I like to install house wrap before the metal roof goes on. I fold the house wrap over the top of the wall so there isn't any way that water can get behind it. My main reason for this is wind blowing rain that might get under the metal. I never thought about condensation doing this.

 

[Richard001]

I have a lean to on my building. Decided to enclose it. Poured a concrete floor. Block on top and then stud walls covered with 3/4 inch plywood and some 3/4 OSB. Covered with house wrap by Carter Lumber Co called R Mor. Top and bottom edge now sealed with brand name sealant tape. The outside walls are under the overhang of 12 inches with a 5 inch D spouting with underground drain tile connected to transfer the water 50 feet away. All building has gravel 10 feet or more around the concrete.
Under the house wrap I am getting moisture/condensation. As high as the roof in places and down. Roof is 5 year old metal, 2.5 or 3/12 slope and no leaks there.
Unsure where the moisture is coming from and do not want it to eventually damage the sheeting. Thoughts?

I did an internet search for the brand that you installed. I can not find it. Are you sure that is the correct name ?

A lot of things can go wrong with outside wrap. If it restricts the moisture movement from the inside to the outside, moisture will from on the inside surface of the wrap.

 

[workinonit]

This time of year here in SC we have condensation issues because of the large temperature swings we experience. From freezing to high humidity warm is the worse.

 

[yanmars]

Under the metal roof is 3/4 inch OSB. The inside/underside and under the eaves also is completely vented. On top of the OSB is a snow guard type sticky membrane.

 

[BlueKnife]

I have a lean to on my building. Decided to enclose it. Poured a concrete floor. Block on top and then stud walls covered with 3/4 inch plywood and some 3/4 OSB. Covered with house wrap by Carter Lumber Co called R Mor. Top and bottom edge now sealed with brand name sealant tape. The outside walls are under the overhang of 12 inches with a 5 inch D spouting with underground drain tile connected to transfer the water 50 feet away. All building has gravel 10 feet or more around the concrete.
Under the house wrap I am getting moisture/condensation. As high as the roof in places and down. Roof is 5 year old metal, 2.5 or 3/12 slope and no leaks there.
Unsure where the moisture is coming from and do not want it to eventually damage the sheeting. Thoughts?

You mention using both 3/4" plywood and 3/4" OSB for sheeting. Why such thick material and why two different kinds? Any chance that was material you already had on site? Maybe had some moisture in it?