No underlament installed


Just had a exposed fastner metal roof installed. Contractor removed old shingles. Then installed metal on battens above osb roof. The problem is he installed no underlayment. Already paid the guy. Don’t know what to do.


Call the inspection department in your town. It is absolutely wrong if the underlayment was not installed. If you have codes in your area they may require the roof be a class A fire rated assembly. A metal roof does not meet that code.


Are you in Canada by chance? From my understanding underlayment isn’t code there. Did your old shingle roof have underlayment? I don’t agree with how they did your job but provided your roof is properly ventilated you shouldn’t have an issue.


No I live in Central Mi. The roofers are Amish and it looks like they did a nice job.
They removed two layers of shingles and paper. I just worried no underlament of any kind. I am probably out the money. Worry about condensation. I heat pole building. Hey thanks for advise. Probably just have to go with it as is.


Oh, its a pole building? If so then I wouldn’t worry about it. Where I’m from here they install metal right on top of 2x4 battens (no underlayment or plywood) on 95% of new construction and existing pole buildings. I still would have used underlayment myself if I was doing the job though.

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Your condensation concerns are legit & your roof deck is likely to rot out because of it.

This will take some time which is how they get away with it.

Exposed fastened metal is not meant for occupied dwellings.


I agree the it should have had underlayment and it would have if I did the job. However its a pole building (I’m assuming not living space). Also the fact that its a short lifespan type of roof leads me to believe it will be leaking badly from the screws and need replaced long before any condensation problems would ever develop. This is why I say I wouldn’t be worried about it.


It’s heated.

In Northern Michigan, it’s the same thing.


If properly ventilated will not all (maybe 90%) the hot air containing condensation exit the ridge vent? And if it isn’t properly ventilated even if they had installed underlayment will not condensation form on the bottom on the underlayment causing the same possible rot anyway? The point I’m trying to make is I feel ventilation is what could make or break this job not the underlayment.


I agree but metal roofs always require an underlayment, so there is that.

I wouldn’t install any pitched roofing system without an underlayment, that is what I was taught by people whom I respect and it has not let me down.

And then we can go on to converse about what I have seen.


I also wouldn’t install a roof (esp metal) without an underlayment and respect you enough that I knew you wouldn’t either. However saying metal roofs “require” it is a vague statement and until a local code official or the manufacturer of that specific metal confirms it’s still debatable.


Thanks for info guys. Do you think I should remove existing metal roof and install an underlament. Or do you think roof will last a couple of years.


Yes it will be just fine for at least a couple yrs, this is a long term thing usually.


Any metal roof over joists with no sheathing will drip extensively from sweating. It is very obvious when it’s not sheathed. Now picture the same sweating going on but on top of the sheathing, unseen. This is going to rot all the sheathing out. Technically metal should not touch wood in any flashing detail and this is large scale, even if it is on battens. Talking about how long it will take makes no sense. You got a job that will damage the integrity of your building.

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Is this a company out of Manton?


I think big rapids area.


Did the roofing come with an optional “condenstop applied to the back of the panel. If so you will be fine.


I would have to check.However because of who installed the roof I doubt it. I screwed up
I caught them putting up last piece of metal .I asked the about underlayment.They said no need. It was only later that my brain started working. I guess I’m stuck with this job.


Do you have a certificate of insurance from them? If not Hopefully they took out a permit, just go to the building dept they should have it on file.


Help me out. What if there is nothing on file.