# Metal Roof Screws Leaking



## tinner666

Exposed screws need maintenance. They're gonna let water in around them, even if you can't see it. Until the wood rots in those spots. 
Every few years, I believe you'll need to go up 1 screw size and replace them all.
Never use the system myself.


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## pyper

I've got a metal roof with screws like you describe.

The roof should have been installed over a waterproof membrane, like felt. If it's not, then it's not on right.

If there's a small leak, it ought to drip off (or worst case down) the screw and hit the felt.

It seems like it should take a long, long, time before the very small amount of water could get past the felt. Mine shows no signs of water on the underside of the roof decking after at least 5 years.

The point of failure is the rubber gasket. Just replace the screws that leak, and don't screw them in so tight.


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## tinner666

Tightness can make some difference. Not much. Listen to the roof installed with exposed fasteners. You can hear it shifting as the metal heats in the morning and trying to find a way to expant between the screws. The metal loosens the screws with all it's movement. The holes around the screws elongate to accomadate the movement.
5 years is a good run without leaks. Bck out a few screws and see if the wood shows signs of dampness yet.

That's why real metal roofs have expansion built into them.

http://www.albertsroofing.com/Tin%20Roofing%20photo_gallery.htm


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## Tom Struble

those kinda of roofs are usually meant for open purlin ag buildings
not houses


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## JDM

Tightening the screws may not actually help, in fact it can make it worse. If you overtighten the screws it can cause them to leak. You need to remove the screws that are leaking now and replace them with #14 oversized roofing screws. You can do the job yourself.


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## WBNC

the ones that i can reach i have tightened just a bit. i did not want the busings to mushroom...:thumbsup:


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## pyper

tomstruble said:


> those kinda of roofs are usually meant for open purlin ag buildings not houses



Screw down metal roofing is becoming very common in the South. It's commonly put over old roofs. In new construction they usually put sheathing on the roof first. Some installers put purlins on top of the sheathing (or old roof) and some don't.

FWIW, my shed has had "5V" metal roofing for 15 or more years (it was there when we bought it). It's open on the bottom, and as far as I can see there are no leaks (I just checked -- the remnants of hurricane Ida just dropped 4 or more inchees of water on us, so if there was a leak it would be easy to spot). It's not even put on with screws, but nails with little neoprene washers.


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## Tom Struble

just because its becoming common dont mean its the way to do it:no:
the more of these roof you see the more problems your going to see with screws leaking
think about it every one of those thousands of screws have to seal perfectly ,the roof on your shed is the place for that product

a conceled fastener roof for a house imo


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## pyper

tomstruble said:


> just because its becoming common dont mean its the way to do it:no:
> the more of these roof you see the more problems your going to see with screws leaking
> think about it every one of those thousands of screws have to seal perfectly ,the roof on your shed is the place for that product
> 
> a concealed fastener roof for a house imo



You make it sound like there's no margin of error on installing the screws.

The fact that my shed, built probably 20 years ago by guys who didn't know what they were doing, still doesn't leak even after 4 inches of rain, suggests otherwise. 

Concealed fasteners sound like they'd be superior, but the screw-through systems seem to be fairly robust. How much more does the material for a concealed-fastener roof cost? It's not like we're going to change anything at this point though, but I'm curious. Actually, if I did get a leak from a screw I would probably be tempted to put a dab of silicon caulk on the screw head.


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## tinner666

"Concealed fasteners sound like they'd be superior, but the screw-through systems seem to be fairly robust. How much more does the material for a concealed-fastener roof cost?" 
I don't know. Doing residential, I've never had reason to price the exposed fastener system. I'm more into the 'century' roof.
I do get many calls to repair/recaulk/rescrew that type though. Never bothered to bid one. I've been under them often and it's a neat sound to her as the sun starts warming those panels. Little twings, twangs, and other noises abound as the metal tries moving under the strain of expansion. Pretty neat!


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## pyper

tinner666 said:


> I've been under them often and it's a neat sound to her as the sun starts warming those panels. Little twings, twangs, and other noises abound as the metal tries moving under the strain of expansion. Pretty neat!



I'm under mine all the time as it heats and cools and it doesn't do that. I wonder what the difference is.


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## tracker911

Felt paper under a melal roof is noware near as good as a old asphalt roof for helping stop leaks. I have been installing metal roofs since metal roofing was first on the market. Hundreds maybe a thousand so far. Had a few leaks but all in all metal is the way to go. The hidden screw roofs are best on homes for that reason but the cost is substantial and probably not worth the upgrade. about double the cost. We have put metal roofs on homes all over Arkansas with the 105 degree summers and 0 degree winters and just have not had probems. Some of the first houses we did had to have whole house screew changes because the rubber on the screws was eroding but the new rubber is much better. I did my own house with 26 gage v roofing and plan to never go up on it again.


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## MJW

Ask your supplier. Steel has no warranty, only the paint. I feel it's an inferior product for homes. It may work better in warmer climates though.


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## Tom Struble

tracker911 said:


> Felt paper under a melal roof is noware near as good as a old asphalt roof for helping stop leaks. I have been installing metal roofs since metal roofing was first on the market. Hundreds maybe a thousand so far. Had a few leaks but all in all metal is the way to go. The hidden screw roofs are best on homes for that reason but the cost is substantial and probably not worth the upgrade. about double the cost. We have put metal roofs on homes all over Arkansas with the 105 degree summers and 0 degree winters and just have not had probems. Some of the first houses we did had to have whole house screew changes because the rubber on the screws was eroding but the new rubber is much better. I did my own house with 26 gage v roofing and plan to never go up on it again.


 
never say never,ive seen those screws actually back out and stainless steel rivets sheared from the movement of the panel


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