Steel roof leaking

[mcgoo]

Screw down roofs are gonna leak sooner or later. you can pull the screws out and put in over size ones. You can do that and caulk em.
I have pitched roof that is not very steep on my barn that was put up in the eighties. Screwed in. We are gonna pull it off, sheath it with plywood and put down new metal that is snap down hidden screws. I have that on a couple newer buildings and wish to heck the barn was done that way to begin with.

I think I'm in the same boat as you.

 

[mcgoo]

From the age you have quoted , have you removed a sample of screws to check the condition of the weather-seal washer? When my parents bought their retirement place the garage leaked. The cause was a perished weather seal washer on the screws. A full set of new screws (and seals) later and problem fixed. The garage was a similar age.
Some posters have commented about the number of screws, is the building in a "high wind area"?

That was the first thing I did. The old owner left behind a bunch of screws. I wondered why until the first rainfall. I don't think I'm in a high wind area. During storms we get gust of maybe up to 80 kilometers an hour.

 

[mcgoo]

To me a lot of folks are missing the main issue. The uninsulated shop is heated and contains a fireplace showroom. It's an ideal situation for ice dams and good old wicking. Roofs, in general, rely on two layers- ice and water shield and or underlayment and a top/main layer which is metal in this case.
Trying to get around that fact is asking for ongoing issues.

I'm just working through what I have and trying to figure it out now. By the way it's not non-insulated basically it's a building within a building that houses the fireplace showroom and the garage. It's also very leaky due to the overhead doors being a little bit small and not trimmed out properly.

 

[moriboy]

In the same boat here. We purchased our ranch a few years back and to my delight it had a 40 X 60 insulated metal shop. To my dismay, I've been chasing down leaks each winter. The roof pitch is 2/12. Here in Oregon we get a little rain. Why someone would build a nice shop and not put the proper pitch on the roof is beyond me.

Needless to say, the overlap seams are not sealed and water will creep up and over the joint and drip on the underside of the metal. This has caused the insulation to deteriorate leaving bare metal in places and I also fight condensation.

I will be pulling the metal sheeting off at some point and adding OSB and felt paper under the metal.

 

[EddieWalker]

Having a problem with my existing metal building. It's slab on grade with concrete block knee walls and stick frame interior with metal siding and roof. The area with the large drive up door is my warehouse. Where the small roll up door is is where my tractor goes and the man door is a fireplace showroom. I have Heating in all 3 but only use it in the tractor area and showroom. The warehouse area needs to be insulated. Problem is I have roof leaks at the metal seams on the tin roof. It's wrecking the ceiling in my showroom and I don't want to proceed with insulating the warehouse area until I solve this issue. What are my options for fixing the leak? I have a friend that does metal roofing he tells me the only way is to pull the tin off the roof put down sheathing and ice sheild and put the tin back down. Right now it's just the tin screw-down to the cross bracingView attachment 499531 . Does anyone out there have any experience with this type of situation or any other ideas?


ATTACH]499528[/ATTACH]View attachment 499529View attachment 499530

Looking at your pictures and ignoring your denial about condensation, I notice the massive amount of staining on your purlins. This is very common in metal buildings without enough venting. Do you have any venting from your soffits to your peak? If there is no air flow along the underside of your metal, condensation will form almost every morning. You might never notice it, especially if you do not have a lot of humidity, but it's there and the proof is on your purlins. To stop the condensation, you either need to create more air flow, or insulate with closed cell foam. Only use closed cell. Open cell is cheaper,has a lower R value for the same thickness, and it absorbs water, which will speed up the deterioration of your metal.

Another option for dealing with condensation is removing the metal, installing OSB and putting roofing paper or some other membrane down that will catch the very small amount of condensation that forms every morning. Most of the time the amount of moisture formed is minimal and you never notice it. Other times you can actually see the water coming off the roof, under the metal and over the paper.

Since your building was built in the 80's, I would guess that the rubber seals on your screws are bad. The 80's where probably the very worse decade for home building materials. The EPA was just getting started and making changes so quickly that manufactures had to keep changing what they where producing. Rubber, glue, paint and plastic where all hit really bad. I don't trust anything built in the 80's.

Please post a close up picture of your screws that show the condition of the rubber gaskets. Are they plump looking, or flat and crushed? Are they cracked or damaged? On a metal roof, the rubber seals on the screws are where most leaks happen.

Please don't fix one thing and ignore another because you don't want to believe there is more then one thing wrong with your roof.

 

[Snobdds]

Looking at your pictures and ignoring your denial about condensation, I notice the massive amount of staining on your purlins. This is very common in metal buildings without enough venting. Do you have any venting from your soffits to your peak? If there is no air flow along the underside of your metal, condensation will form almost every morning. You might never notice it, especially if you do not have a lot of humidity, but it's there and the proof is on your purlins. To stop the condensation, you either need to create more air flow, or insulate with closed cell foam. Only use closed cell. Open cell is cheaper,has a lower R value for the same thickness, and it absorbs water, which will speed up the deterioration of your metal.

Another option for dealing with condensation is removing the metal, installing OSB and putting roofing paper or some other membrane down that will catch the very small amount of condensation that forms every morning. Most of the time the amount of moisture formed is minimal and you never notice it. Other times you can actually see the water coming off the roof, under the metal and over the paper.

Since your building was built in the 80's, I would guess that the rubber seals on your screws are bad. The 80's where probably the very worse decade for home building materials. The EPA was just getting started and making changes so quickly that manufactures had to keep changing what they where producing. Rubber, glue, paint and plastic where all hit really bad. I don't trust anything built in the 80's.

Please post a close up picture of your screws that show the condition of the rubber gaskets. Are they plump looking, or flat and crushed? Are they cracked or damaged? On a metal roof, the rubber seals on the screws are where most leaks happen.

Please don't fix one thing and ignore another because you don't want to believe there is more then one thing wrong with your roof.

Exactly. Just looking at the underside of your roof tells me there is a major condensation problem. You probably have roof leaks from bad screws too, but understand that you have multiple problems going on here.

On a side note, it amazes me the amount of professional builders that really don't understand roofing and how materials interact with each other.

 

[nosurprise]

Seal O Flex or Hydro-Stop may be a cheaper alternative. Not a cheap product but less expensive than removal and replacement. It's a elastomeric system that works on this application. Surface cleaning, prime metal, foundation coat then a 40" woven polyester fabric imbedded in the foundation while brushing in the fabric a roof mechanic is coming behind with a second coat of foundation. Followed by 2 coats of the finish coat. We have used this system on everything from pole barns to Turkey Point Nuclear power plant metal roofs with issues. May be worth a look as an alternative......

 

[PILOON]

I was mandated to do extend a chalet living area and that called for pulling an 8 year old metal roof.
The owner hated the 'tin roof rain sound' so the handyman laid the tin roofing over OSB sheeting.
That pulled (galvanized) metal was total scrap as the underside was well rusted and the OSB was black from mildew condensation.
The metal sweated with the OSB acting as a sponge and that trapped the dampness.

The underside of a metal roof needs ventilation!

Also have a small shed with metal roofing. Come spring with snow on the roof it rains inside simply due to the condensation of warm moist air against the cold metal roof underside, and I really mean rain as it simply drips constantly.

 

[beowulf]

I have a couple of buildings with metal sheet roofing that I built. I overlapped the seams more than recommended and so far no leaks. On an older metal roof attached to the barn and open on all sides - like a porch - there were leaks. I simply put more metal roofing (light weight) over the top with the center of the new panels lapping the old seams. This could be expensive if you have a lot to cover, and you would need to consider the weight as well. But for me - no more leaks.

 

[civilian]

I was mandated to do extend a chalet living area and that called for pulling an 8 year old metal roof.
The owner hated the 'tin roof rain sound' so the handyman laid the tin roofing over OSB sheeting.
That pulled (galvanized) metal was total scrap as the underside was well rusted and the OSB was black from mildew condensation.
The metal sweated with the OSB acting as a sponge and that trapped the dampness.

The underside of a metal roof needs ventilation!

Also have a small shed with metal roofing. Come spring with snow on the roof it rains inside simply due to the condensation of warm moist air against the cold metal roof underside, and I really mean rain as it simply drips constantly.

Doesn't the metal roofing when applied over OSB need a vapor barrier under the metal? That is how mine is installed on my garage. On my unisulated pole barn, the metal is on top of foam sheets supported by purlins. However I get some leakage during a hard drive rain storm. I think the rain is blown into tidge vent, travels down foam to a spot to leak through. Not sure if the seams on the foam were taped. The other problem I see with metal over purlins, is the snow loading. I think weight of snow slightly bends metal roof and pulls on screws. This allows for potential leakage. Jon