|
|
| I have a Morton pole barn that really sweats this time of year. With cool nights below freezing and days warming up above freezing it’s like raining in the barn. Roof is metal nailed to 2x4 purlins with a full ridge vent. Usually by noon it dries up but I am worried what this will do the purlins in time. Floor is stone. It is so bad that I would not put a load of seed in the barn without covering. Morton’s fix is to remove the roof and either but their insulation board down and re-install the original sheet metal or replace the roof with new metal that has the insulation fabric bonded to the metal. Either way … expensive. Any suggestions?
|
|
| |
|
| I don't know where you are located, but you need to reduce the moisture and/or add insulation. For the ridge vent to be effective you need a way to introduce outside air at the outside walls (soffit area) and mix with the inside air and exhaust out through the rige vent.
|
|
| |
|
Central Illinois | I do not have an answer, but I have an FBI building with a dirt floor that is absoulutly terrible for collecting frost under the roof and then dripping, and I have a Morton with a gravel floor that only has a small amount of frost and drips very little. But you said you have a stone floor, but I have been wondering if it would help if I covered the dirt floor with a thick sheet of plastic and then a layer of rock would that help?? Maybe a layer of plastic would help with your floor as well ?? |
|
| |
|
Peebles OH | Plastic vapor barrier under the gravel, that would be a lot of work as well. |
|
| |
|
NW Washington | You have to keep the warmer moist air in the building from touching the cold metal roof and then condensing liquid water. Think beer can in the summer. Seems to me like insulation under the cold metal roof is your best answer. How to best do that is another issue.
Reducing moisture by sealing off the floor would help too. |
|
| |
|
ECIL | We built a FBI shed a couple of years ago. We have concrete in one end, gravel in the other.. The way ours was built, we had to add about a 10 inches of road pack to get it up to level. The first winter, after we built it, the roof dripped like crazy. Before we dumped the gravel in, we put down a real heavy plastic tarp. We then carefully spread the road pack over the tarp, and compacted it. The next winter, after doing that and putting a vapor barrier under the concrete, the condensation forming under the roof, was reduced substantially. You might also consider installing some type of power vent, up high, in the end. Perhaps a "Big Ass" type ceiling fan might also work to circulate air. |
|
| |
|
Southwest Oklahoma | I don't think ventilation will help. The fully ventilated carport here is dripping this morning. |
|
| |
|
| This is what is happening – warm moist air from inside of your building is rising. When it contacts the underside of the cooler roof steel, it is condensing. Over time, not only will the purlins develop unsightly water streaks, but there is also the potential for rot. It is very possible for moisture to collect around the shanks of the roof screws (or, hopefully not, nails) and rust them, causing leaks. Many steel manufacturers will not warranty their products as roofing, unless installed over an insulated vapor barrier.
Ventilation alone, is not going to solve the problem. Even a roof only building, will have the same issues.
How to solve from where you are now….
Least expensive, would be to place an insulated vapor barrier on the underside of the roof purlins. In order for this to work, it requires all of the seams to be tight. I’d recommend a product which has tabs with adhesive pull strips, rather than square edges which must be taped. Look at www.buyreflectiveinsulation.com for more ideas.
As you say the roof is nailed on – removal of it and trying to reuse the steel panels is not going to happen.
Spray foam is probably going to prove to be less expensive than a new roof.
Sad to say this….but for probably about two bits per square foot of roof surface, at time of construction, we wouldn’t be having this conversation.
|
|
| |
Pole Barn Sweating
