# Metal Roof Installation Dilemma



## dianek (Oct 27, 2012)

Hello All,

I have a 30 x 40 stick garage that was built last summer. Attached is a photo taken last summer while under construction:

http://www.emptynestestatesales.com/Images/garage4.jpg

My husband and I hired my brother, who is a union carpenter in SF, to come up to the Upper Peninsula of Michigan and build it. 

To make a long story short, we had a plan drawn up, but somehow my husband went along with my brother's recommendation to install the metal roofing directly over purlins with no underlayment. The plan called for OSB and felt.

So now, basically, we have a garage that is not closed in. We live in the country, in the woods, actually, and anything can fly (or crawl) in through the end s or the ridge vent. In the summer, it gets warm up there so it's attractive to wasps and flies. There are also two significant leaks in the roof of the loft. Pretty hard for a call back when your builder is thousands of miles away. 

Bottom line: I need to make this right. I store antiques in the loft and can't have water/condensation damage, nor can I have mice, bats, and flying insects. Do I have any other options other than taking down the metal and installing sheathing and felt and putting the metal back up?

I have been all over the web looking for answers. I really would appreciate the opinion of professionals. 

By the way, I live in snow country. I'm not sure of the pitch of the roof, but I don't think snow could accumulate on it. We have had some unusually wicked rainstorms, though.

I'd especially like to know which system/products pros would recommend.

This project is on my shortlist for Spring. Just trying to get a good game plan.
Thanks.
Diane


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## seeyou (Dec 12, 2008)

The rake trim hasn't been installed yet.

Nice looking garage, by the way.


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## dianek (Oct 27, 2012)

*seeyou, thanks*

the fact that it is such a nice building only adds to my frustration and disappointment that the roof system got screwed up. 

That picture was taken before garage doors and the rakes were finished off.


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## seeyou (Dec 12, 2008)

Do I have any other options other than taking down the metal and installing sheathing and felt and putting the metal back up?

Rip some rigid insulation to the width between the rafters and install it against the bottom of the purlins. Foam the seams together.


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## dianek (Oct 27, 2012)

Would that form channels to run off water from any leaks? Both of the leaks I have now are dripping off the purlins. Seems like it would look pretty sloppy. 

I wasn't planning to finish off this space. I only need an area that is rodent and insect proof and dry. Also not sure how it would keep critters from coming in, though maybe it would.


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## seeyou (Dec 12, 2008)

dianek said:


> Would that form channels to run off water from any leaks? Both of the leaks I have now are dripping off the purlins. Seems like it would look pretty sloppy.
> 
> No. The leaks need to be fixed. If the rigid foam is ripped on a table saw to fit tight, it will be fairly attractive - no better or worse looking than purlins and the bottom of the roof. The foam will reduce or eliminate condensation, which should be minimal anyway if you're not conditioning the space. It will also cool the attic down a little.
> 
> I wasn't planning to finish off this space. I only need an area that is rodent and insect proof and dry. Also not sure how it would keep critters from coming in, though maybe it would.


I can't envision how "critters" could get in if the roof is installed and trimmed out properly, purlins or solid. Nothing is really insect proof. Maybe your best option is to take the roof off and re-sheath as you said. But, you're likely more likely to have leaks develop in roof panels that have been installed/removed/installed especially if they leaked in the 1st install.


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## dianek (Oct 27, 2012)

Thanks. That's beginning to make more sense. So, would the foam be right up next to the metal, or should there be air space. If so, how much? Also, how would the foam be attached?


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## seeyou (Dec 12, 2008)

dianek said:


> Thanks. That's beginning to make more sense. So, would the foam be right up next to the metal, or should there be air space. If so, how much? Also, how would the foam be attached?



It would be below and against the purlins. Glue & screw.


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## dianek (Oct 27, 2012)

Another question, if you don't mind. I do appreciate you taking the time to address some of my concerns.

If I did decide to remove the roof and install sheathing and felt, would purlins be required on top of it, or would the metal be attached to the sheathing? My concern would be raising the profile of the roof. I suspect the drip edge would need to be removed in any case.

I'm looking at a building blog and it shows the metal being installed without purlins. Not that I believe everything I read on the web. 

http://www.thebuildingblox.com/2012/07/new-home-progress-week-5.html

Thanks again.


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## AndyWRS (Feb 1, 2012)

I would take it off and install ply or OSB and a HT synthetic underlayment if your installing the roofing direct to deck.

Maybe the plans called for felt paper to the deck then install purlins on top of the felt, then you would install your metal roofing over the purlins. If this is the case, then your drip edge would need to be larger to cover the sheathing and the purlins.

Will it not have condensation accumulate on the underside of the panels as it is installed now?


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## funfool (Oct 5, 2012)

I think your buddy contractor was correct in not using sheathing, basically it is not required and saved you the cost of material and labour of installing it.

If it is leaking, this is a flashing issue and needs to be corrected.
Looking at the photo, it is hard to see where it could be leaking. Will need to be there and then get on the roof to inspect to find the issue.

As far as bugs go, from the photo, I would add a flashing at the bottom end of the panels, would go over framing and then hang over the Facia a inch or so.
Then there is a pre formed foam gasket that the metal roofing manufacturer you purchased the roofing from, should have available for purchase.

Basically would remove the screws from the panels so you could lift them enough to slide in the new flashing.
Then with the foam gasket, it has a peel and stick way to apply it, peel off the paper and stick it to the new flashing you just installed a few inches back so you do not easily see it from the ground.
This will bug proof the roofing panels on one end, it will not fix the leaks.
You also could remove the flashing from the peak and loosen the panels and apply same foam there.
Again it is made for bug proofing and such things, is not going to fix a leak.

Without seeing any penetrations through the roof like plumbing or a chimney, hard to understand where the leak is coming from.


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## dianek (Oct 27, 2012)

Thanks, Andy. I am learning way more than I ever wanted to know about decking and metal roofs. 

I wish I had known this stuff while the building was under construction.


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## AndyWRS (Feb 1, 2012)

If you zoom in on the ridge at the gable it appears to have had a ridge vent cut in ( the sheathing appears to be cut about 1.5" down from actual gable peak on both sides ). With no penatrations the leak is probably just rain blowing it at the ridge.


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## dianek (Oct 27, 2012)

Actually, it rained really hard a couple of days ago and I went out with a flashlight and found both leaks. I don't think it's coming from the flashing. Both leaks had drips coming off purlins (not the same ones) and I think it might be leaky screws. I had one other leak months back and was able to stop it by wedging a shim between the purlin until my brother came back and got on the roof and tightened it.

Of course, I could be mistaken.


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