My new metal roofing problem

[Beeman]

I've got a 5 rib panel painted metal roof covering my deck. I have plenty of dislikes about it but now have a new problem. The roof was installed with the correct screws installed in the flats as the manufacturer said is correct. After 2 years I have developed leaks at screws which are the screws that match the color of the roof and have a metal shield over the rubber washer. I marked my leaks at the underside and removed the offending screws. It seems since these are self deilling/tapping screws the metal shaving from the drilling was caught between the rubber washer and the metal roof. this cut the washer and gave a path for water. Now this wasn't a large leak but my roof is exposed underneath so I could see the wood absorb the moisture and marked the screws.
Since having this roof installed , by a professional (Hah!) I have since come to find it's many shortcomings. I will have to remove the roofing and deck the rafters before re-roofing and since these panels all have screw holes in the flats I don't think I want to use them again and might not be using metal at all.
In my quest for info on metal roofs I came across another problem with them. When installed over an existing roof with wood strips laid on the roof there is a problem with condensation on the bottom of the metal causing the wood strips to deteriorate over time.

I know many have metal roofs and love them and I am still doing research on whether or not I will use metal so far these are some things to watch your roof for and to avoid if installing.

[agmantoo]

It is for the reasons you mentioned that most commercial buildings have standing seam metal roofs and not the exposed fasteners.
There is a jumbo screw that you could buy and install to replace the existing fasteners. This jumbo fastener was designed to address the problem you have experienced.

[whitewolf]

Our "small" business is installing metal roofs. So here goes with our opinions (and as you know, everyone has one)....You are probably right about the self tapping screws and washer and metal shavings. We are curious about which screw they used. There are two that people in our area use. (wish I could send pics, but am not set up to do so). One is the hexagon screw with a curved metal cap and rubber washer. The other is basically the same except the metal cap has a very small ridge that comes down over the rubber washer and once it is screwed down you basically cannot see the rubber washer. That "ridge" allows it to go down just "so" far against the metal. We use the first one without that ridge. We haven't experienced this problem that you are speaking of. We are not saying that it is impossible though. The thing about condensation: We install alot of roofs this way (over exisiting shingle roofs with 1X4's stripping it). If the roof is properly vented, you shouldn't have much condensation, if any. This has been our experience, but as I said before, anything is possible. If I can be of any help answering other questions, or giving you our opinion, please let me know.

Whitewolf

[Farmer Willy]

If you want to get rid of the roof I'd be glad to take it off your hands. I use the 5 v on all my outbuildings, use the galvanized nail/washer through the rib. No leaks anywhere to date.

[punkrockpilot]

How about deburring the hole and then using new longer screws, a dub of silicone and have some one hold a backer board underneath while you put the new screw in.

[Beeman]

Originally Posted by whitewolf

Our "small" business is installing metal roofs. So here goes with our opinions (and as you know, everyone has one)....You are probably right about the self tapping screws and washer and metal shavings. We are curious about which screw they used. There are two that people in our area use. (wish I could send pics, but am not set up to do so). One is the hexagon screw with a curved metal cap and rubber washer. The other is basically the same except the metal cap has a very small ridge that comes down over the rubber washer and once it is screwed down you basically cannot see the rubber washer. That "ridge" allows it to go down just "so" far against the metal. We use the first one without that ridge. We haven't experienced this problem that you are speaking of. We are not saying that it is impossible though. The thing about condensation: We install alot of roofs this way (over exisiting shingle roofs with 1X4's stripping it). If the roof is properly vented, you shouldn't have much condensation, if any. This has been our experience, but as I said before, anything is possible. If I can be of any help answering other questions, or giving you our opinion, please let me know.

Whitewolf

The screw is a hex with a cap but when tightened down I can see the edge of the rubber washer.
The lower edge of the metal roof should have a piece under it according to the manufacturers which would prevent insects and water from coming under the metal panel. this would prevent any ventilation. Even with ventilation, my roof is on an open deck so there is nothing but ventilation, the roof drips and frsts when the temp changes. Do you put any underlayment over the existing roof shingles before installing the wood strips? Every manufacturer said that was required.


As far as giving the roof panels away, I don't think so. I'm sure I can find an outbuilding to use it on.

[Boleyz]

I've installed a lot of metal roofs and will never install anything else. I've put them over existing roofs, both with 1X4 Lathes and directly on shingles.

Never had a problem.

My new house has a metal roof. What I do is put up the lathing (2X4's) and then measure to the center of each lathe board. Then, on the ground, I take 4-5 pieces of metal and stack them and chalk a line, transcribing the measurements of the lathe centers to the stack of metal.

Then, I simply take a small drill bit and drill a hole where every screw is going to go.

Hoist a piece to the roof, square it up, and Voila! The holes are there, awaiting the screws, which start and go in easily and straight, with no dents and no burrs.

Then, I check my measurements, because lathing may not always run perfectly straight, and do another 4-5 pieces, drilling the holes on the ground through 4-5 pieces at once.

If it's a new roof, I put a 4-R piece of "Bubble Insulation" (looks a lot like bubble wrap for mailing), under the metal in direct contact with the underside of the metal. This stops condensation as the metal warms up from the chill of morning. Without insulation under an open structured roof, it will look like it's raining inside as the day warms the metal.

I've never heard or seen the problem you mentioned about boards over shingles with metal and condensation in that small air space. It could be your climate is more severe than mine...

[ET1 SS]

I installed my own metal roof onto our home [well I did get help hauling the 20 foot panels up there, so I can't say that I did it all myself]. It is a 2400 sq ft building. I did it last summer. Some of the screws did leak a little this spring. And I have gone up and fixed them. It did appear that the burs had tore up the rubber gasketing. I backed out the leaking screws, shot the hole with silicone and put in new screws.

Now I know that it is a new building, but I think that this should fix it.

Still for the price and ability to erect it myself, I would not have wanted to be doing it with wood.

For 2400 sq ft of roofing, i msut ahve used 20 pounds of screws, and I think that I had to go back and fix maybe 6 of them. So I dont think that was too bad.

[whitewolf]

I thought you said that "professionals" put this roof on?? (don't you just love those types of professionals?) You need some type of vapor barrier definately. I didn't understand that you were talking about your "deck" roof having a condensation problem. I thought it was another house that had the problem and you had screw leaks on your deck. My mistake. Another thing that MIGHT be your problem with the screws is that they were installed too tightly. Hard to diagnose on line. These roofing professionals......did they not give you a workmanship warranty or have they already disappeared from the earth.....that happens alot around here......here today...got the money....gone tomorrow.

As for reusing the metal, well we have came in behind people and used the metal that was reusable.....can be very time consuming, but it may be worth it to you, especially if you are going to do the job yourself. Good luck.

Just a side note: Anyone that is getting a roof done, please get references, workmanship warranty, and material warranty. If they can't give you these 3 things, you probably will be better off not using them. If you do this, you USUALLY will come out OK.

Whitewolf

[PyroDon]

Sounds like they over tightened the screws crushing the neophrane washer.
get a new screw and replace the old one being careful not to over tighten.
If you must use a sealent use a polyurathane , silicone has its uses but on a roof is not one of them . Butyl rubber would be my second choice though its like working with hot bubblegum .
condensation shouldnt be a major concern if its vented .

[Beeman]

Originally Posted by PyroDon

Sounds like they over tightened the screws crushing the neophrane washer.
get a new screw and replace the old one being careful not to over tighten.
If you must use a sealent use a polyurathane , silicone has its uses but on a roof is not one of them . Butyl rubber would be my second choice though its like working with hot bubblegum .
condensation shouldnt be a major concern if its vented .

Screws aren't overtightened, metal shavings caught under rubber washers are the problem. I agree about silicon it never worked on autos as it relesed from the smooth metal. Condensation is definetly a concern, as I stated my wide open deck roof drips like a rain forest and it can't get any more ventilated.

[Boleyz]

Originally Posted by PyroDon

condensation shouldnt be a major concern if its vented .

It IS a problem...my barn doors can be wide open and my eaves are not covered. In the winter and spring, when we have a very cool night, followed by a very intense sunshiney morning, un-insulated metal roofs WILL condense water and drip...no mater how it's vented.

The reason is because metal in direct sunlight will heat much more rapidly than the air inside a barn after a cold night.