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Posted: 12/29/2011 1:17:36 PM EST
So, after years of chasing leaks, I've finally figured out that the metal roof on my shed/shop condenses and drips. In some places, the insulation got so water logged that it fell down. The shop is heated so naturally this is more of a problem in winter than summer. Is there a quick and easy fix like mopping the whole thing in tar or am I F––k'd ? Thanks in advance for the replies.
Link Posted: 12/29/2011 1:28:50 PM EST
Sounds like not enough airflow or venting.


Is the insulation just flat against the metal roof?

Describing how it's all constructed would be beneficial, especially if the insulation is backed with a vapor barrier (retarder I guess) layer.


Hopefully people that know more about it come along!
Link Posted: 12/29/2011 2:24:00 PM EST
If you are heating with propane that in itself dumps loads of moisture into the air of the heated shop and then when it cools that moisture has to go somewhere.

Just before you leave the shop open all the doors and let the hot moisture laden ait out.

(was I correct in guessing you were heating with propane? Not shure if natural gas acts the same but I suspect it would ?)
Link Posted: 12/29/2011 2:37:16 PM EST
Try spray form insulation
Link Posted: 12/29/2011 5:32:28 PM EST
Originally Posted By Madcap72:
Sounds like not enough airflow or venting

this is the problem.

solving it will be easy or complicated, depending.

ar-jedi

Link Posted: 12/29/2011 5:37:22 PM EST

Originally Posted By ar-jedi:
Originally Posted By Madcap72:
Sounds like not enough airflow or venting

this is the problem.

solving it will be easy or complicated, depending.

ar-jedi

What round for venting ceilings!

Link Posted: 12/29/2011 5:43:14 PM EST
Originally Posted By miker84:
So, after years of chasing leaks, I've finally figured out that the metal roof on my shed/shop condenses and drips. In some places, the insulation got so water logged that it fell down. The shop is heated so naturally this is more of a problem in winter than summer. Is there a quick and easy fix like mopping the whole thing in tar or am I F––k'd ? Thanks in advance for the replies.




Need more info.

Since you're in MS, you shouldn't have to heat in TOO cold temps. That makes things easier.

What's your heat source? If it's UNVENTED gas (propane or natural gas) that's a big part of your problem. UNVENTED gas heaters...and any kind of unvented heater....introduces a TON of moisture into the air. This moisture rises with the heat. Being a vapor, the moisture moves past the insulation (fiberglass?) and condenses on the cold roof. It then drips back down.

You first need to reduce the moisture level in your shop. You then need to insulate the metal to push the condensation point farther from the metal. You then need a vapor barrier to prevent the moisture from reaching the metal in the first place.

There are several ways to tackle this. None of them are cheap.....sorry to break it to you! First thing is to first make sure that you aren't putting excess moisture back into the shop. Then, you have to PROPERLY insulate the ceiling.

The easiest way to fix it would be to spray foam the ceiling with at least 2 inches of closed cell foam. But....it's gonna be $$$$. Then, reduce the moisture content in the air. The advantage of the foam is that it will be a lot cooler in your hot summers there in MS.

If you can post pics, we can make better recommendations....and we love pics!!
Link Posted: 12/29/2011 8:46:28 PM EST
[Last Edit: 12/29/2011 8:46:45 PM EST by Madcap72]
I know coastal MS, and LA get colder in the winter than most would think.


Working in Houma La, an hour south of New Orleans, the overnight temperature would drop to freezing. I thought the "Beware ice on bridge" sign on the road to work was a practical joke until my first winter there.
Link Posted: 12/29/2011 9:48:42 PM EST
Thanks for the replies.

Electric heat out there. This time of year, its about 28-30 in the mornings.

I'll get some pics later. The insulation (what's left of it) is yellow fiberglass with the white plastic cover. Basically, they laid it down and then screwed the roof on top of it
( yellow side against the roof panels). This was a bartering deal and in hindsight, I should have done some things differentl. The way its made, I'd have to spray foam or something to get coverage so that there's no space between the insulation and roof panels.
Link Posted: 12/30/2011 8:07:12 AM EST
What kind of shop? Are you doing something that produces extra moisture? (drying lumber or some other wet material?) Is there moisture in the ground or from the roof that is makeing its way
under the floor?
Link Posted: 12/31/2011 10:24:51 AM EST
Not drying wood or anything like that. Its a 24 x 30. I use it for working on bikes and cars, and also do some reloading out there.

This pic shows the inside. The slope is left to right and it is a rather shallow slope. This is a section where the insulation got water-logged and fell. It's dry today, but on cold wet winter days, you can see the condensation build up like a coke can. I keep it at least 50 out there when I'm not using the shed, and crank it up to 60 or so when I'm out there.

Link Posted: 1/1/2012 7:27:19 AM EST
[Last Edit: 1/1/2012 8:06:19 AM EST by coldbore141]
Originally Posted By miker84:
Not drying wood or anything like that. Its a 24 x 30. I use it for working on bikes and cars, and also do some reloading out there.

This pic shows the inside. The slope is left to right and it is a rather shallow slope. This is a section where the insulation got water-logged and fell. It's dry today, but on cold wet winter days, you can see the condensation build up like a coke can. I keep it at least 50 out there when I'm not using the shed, and crank it up to 60 or so when I'm out there.

http://i588.photobucket.com/albums/ss328/miker84/ARFCOM/2011-12-31_14-10-51_554.jpg


Miker,
IMHO: you will need to somehow get an airspace between the metal and insulation that has free flow air venting. I have a conventional type metal roof but when we installed it I was warned not to insulate tight against the metal for the very reason of condensation. We used ridge vent, vented the lower edges and put vents in the gables of the building...........

I do remember seeing sprayed on insulation on one of thos round type steel buildings a few time though and that seemed to work ok.
Link Posted: 1/8/2012 7:18:25 AM EST
Spray foam. We had the same prob at work. Unless the insulation is in contact with the metal roof we had condensation. Cut out all the saggy stuff sprayed the foam no probs since. Its been about 4 years now.
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