# Who can discuss standing seam ?



## Poodle Head Mikey

So far we have only installed metal roofing as steel sheets such as Century Drain. But a pending project is going to be standing seam in .032 aluminum.

I have some questions - 

The existing deck is T&G.

Is a vapor barrier required?

Any benefit or deficit to furring up to create an air space between the metal and the wood deck?

If we do fur up - is the metal roof still walkable? <g>

One issue is that the ridge line has a sag which we are supposed to take out. This will certainly require some kind of shimming. But can we just stringline some purlins level? Or will plywood be required under the metal?

Do any of you routinely install standing-seam?

BTW: The chosen profile is mechanical compression seam - not snap-lock.


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## Grumpy

There are many metal roof decking underlayments. You would need one. I always install my standing seam on the substrate over the underlayment and see no rason or benefit to fur. Definetly not walkable if you fur. I do not routinely install standing seam but do install a few small jobs every year.


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## Poodle Head Mikey

*Can you give me some examples of the "many underlayments"?*

What I have somewhat settled on this project is to strip the shingles and etc. to wood decking. 

Stringline and shim the deck level (not overall - just take out the low spots) with left-to-right furring on 12" to 16" centers.

Then re-sheath the entire shimmed-level surface with plywood. 

Then put down 1" foam board.

Then install the standing seam over the foam board.

It's about 35 square total but luckily broken up into multiple planes of 5 square or less each.

Will I need underlayment over the foam board?

stephen
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Grumpy said:


> There are many metal roof decking underlayments. You would need one. I always install my standing seam on the substrate over the underlayment and see no rason or benefit to fur. Definetly not walkable if you fur. I do not routinely install standing seam but do install a few small jobs every year.


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## Interloc

YES put underlayment!


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## red_cedar

never mind


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## kam13

Poodle Head Mikey said:


> What I have somewhat settled on this project is to strip the shingles and etc. to wood decking.
> 
> Stringline and shim the deck level (not overall - just take out the low spots) with left-to-right furring on 12" to 16" centers.
> 
> Then re-sheath the entire shimmed-level surface with plywood.
> 
> Then put down 1" foam board.
> 
> Then install the standing seam over the foam board.
> 
> It's about 35 square total but luckily broken up into multiple planes of 5 square or less each.
> 
> 
> Will I need underlayment over the foam board?
> 
> stephen
> ----------


YES always use underlayment on residential metal roofs.....but just play devils advocate there is plenty of wood shingle with no felts but they breath .....condensation is an issue with metal .http://www.matteoguttersystems.com/


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## Poodle Head Mikey

*That was two years ago <g>*

What I did was to roof-nail down foil faced foam board over the plywood deck and then foil taped all the joints. 

I sure hope that is sufficient because getting all that aluminum roofing back off there would be A Job. <g>

I opened up one double rolled seam to replace a single panel and it took me all day. <g>

PHM
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kam13 said:


> YES always use underlayment on residential metal roofs.....but just play devils advocate there is plenty of wood shingle with no felts but they breath .....condensation is an issue with metal .http://www.matteoguttersystems.com/


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## Poodle Head Mikey

*Does it condensate on the bottom too ?*

I notice that on standing seam roofs in NJ the gutters often drip water until mid morning even when it has not rained - so it can only be condensation running off the metal. It makes me wonder if the underside gets and stays wet?

In Florida the last Century Drain also stayed wet every morning until the sun was well up - often until nearly noon. It all makes me wonder what is happening under the metal. <g>

What do you all think?


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## altmartion

Poodle Head Mikey said:


> I notice that on standing seam roofs in NJ the gutters often drip water until mid morning even when it has not rained - so it can only be condensation running off the metal. It makes me wonder if the underside gets and stays wet?
> 
> In Florida the last Century Drain also stayed wet every morning until the sun was well up - often until nearly noon. It all makes me wonder what is happening under the metal. <g>
> 
> What do you all think?


my roofs do the same here in ny. I am in the process of fixing some venting issues causing serious condensation and other problems. I have done a few standing seam roofs. normally the manufacture gives installation options to stay within the warrantee. around here most contractors use furring strips for that air gap. I have done the same with few I did. you can lay it directly on an underlayment but it needs to be a special grain or something like that. but other manufacture may be different. in my head I think furring strips are better for longevity of the metal. I think if without an air gap it will rot away faster. this is just my opinion. I am a mechanical contractor, not a roofer. I know you from another site and know you pay attention to details like these. is this for a customer?


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## Poodle Head Mikey

*I have standing seam on my house in Solar White*

So of course I notice that dripping water from the gutters there more than on other roofs. <g>

People noticed and liked the roof and it seemed like a cool idea to install some for other people. But I have too many other things going on to devote sufficient time to yet another business - so that was that in NJ. 

All the metal roofs in Florida have been for houses that I own.

PHM
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altmartion said:


> my roofs do the same here in ny. I am in the process of fixing some venting issues causing serious condensation and other problems. I have done a few standing seam roofs. normally the manufacture gives installation options to stay within the warrantee. around here most contractors use furring strips for that air gap. I have done the same with few I did. you can lay it directly on an underlayment but it needs to be a special grain or something like that. but other manufacture may be different. in my head I think furring strips are better for longevity of the metal. I think if without an air gap it will rot away faster. this is just my opinion. I am a mechanical contractor, not a roofer. I know you from another site and know you pay attention to details like these. is this for a customer?


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## wfduggan

yes on underlayment. There are systems that "say" they don't need them, but the underlayment helps kick the water out if there is ever a leak. Metal roofs leak. Typically sealant used at details fails and then the leaks start. It's a matter of time. The feild usually isn't the problem. The underlayment keeps those leaks from becoming damaging to the interior or substrate. If you're using foam board under the metal, same deal.


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## TedLeger

*Standing Seam*

Apparently, the zoning codes for standing seam roofs are different here in Louisiana than many other states. Glad I tried this forum out so I can check out all the different codes for different areas. It is a considerable difference in different states with certain applications.


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## Poodle Head Mikey

*What's different about Louisiana metal roof codes ?*

I was under the impression that Dade County FL had the toughest standards. I think they require a 200 mph wind test result.

What does Louisiana require? And how are their codes different in general?

PHM
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TedLeger said:


> Apparently, the zoning codes for standing seam roofs are different here in Louisiana than many other states. Glad I tried this forum out so I can check out all the different codes for different areas. It is a considerable difference in different states with certain applications.


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