Metal Roof, Exposed or concealed fasteners?

[TheWire]

I'm getting close to needing to roof our 20x32 1.5 story http://countryplans.com/smf/index.php?topic=4640.0 and was looking for feedback on metal roofs.  It appears the decisions are exposed or concealed fasteners, gauge and finish type.  I'm leaning towards 16" wide concealed fastener roofing from Menards.  Its more expensive than ribbed exposed fastener pole barn type roofing and it requires more bending at the bottom.  However it looks more finished and doesn't have the openings in the corrugations at the eave to deal with.  Has anyone had good or bad experience with the concealed fastener metal roofing?  Is it worth the extra expense?

Thanx,

Jerry

[Redoverfarm]

Jerry is that a standing seamed roof you were looking at?  As far as the other metal roofing they make a seal that is laid on the drip edge portion of the sheeting/perlins that conforms to the peaks and valleys of the metal.  They also have a low profile fastner which uses a "torx" head screw rather than the hex head in the past. It is lower profile and is not as visible and the leaves and debri will not hang up on them as in the past.

[TheWire]

Yes I was looking at the standing seam.  I guess I'm concerned about the seal/screw gaskets on a exposed fastener metal roof deteriorating over the years. What type of roof did you use on your place?  Do you know what gauge it was?

Thanx,

Jerry

[glenn kangiser]

I have put up about 300 steel buildings since 1976. 

I have never had a seal go bad as they are covered with a steel cup washer.

You should get a clutch drill or depth sensing screw setter gun and set it so that the seal just squashes to the edges of the washer. Overtightening can excessively squash the seal but does not usually destroy it.  Extreme overtightening it will posibly extrude most of it out or tear it.

[Redoverfarm]

Jerry I used "Lifetite" 28 ga. There is available 26 ga in some colors.  Metal roofing has ben used for a # of years and if installed correctly I don't think the seals will go bad.  With saying that the majority of faults that I have heard is that when it is installed the installer tightens it too much to the point that the rubber seal splits.  If it is tightened to the point that it just buldges to the outer portion of the screw then thats enough.  If you use a torque adjustment to limit that you would be better off. Although that is only good as long as the substrate is the same and doesn't have less or more density from one location to the other.  

A friend of mine helped me with mine and has done hundreds and he has yet to be called back because of the gasket on the screw.  Maybe one that was left out by the workers.  The main points of leaks is the flashing itself around flue, chimneys and vent stacks where they were not done correctly. One point he made about skylights is "don't do it".

Another thing I have noticed in various post that when owner/builder puts it on they use way too many screws.  A row of 36"-40" apart is all that is required as you climb up from the eve.  3 screws per row per sheet is a plenty.  The only exceptions is the eve where the wind could possibly catch and a little more frequently there is required.   And at the ridge there is no need to screw the sheets at the top and then try to put on the ridge cap.  Just use the ridge cap screws to hold it and the sheeting down at the top.  

The screws that I used are new and appear to work better as far as debri hanging up.  The basic shank is the same only the head is different. Probably 1/8"+ protruding up with a round over edge.

There is a multitude of metal roof companies and manufacturers out there and I am sure you will find something that suits your taste.  Good Luck on your project  

[phalynx]

We went with the Pro Snap 100 roofing on ours.  It was concealed screws on it.  I was very please with how it installed.  Very simple.  We chose 22 gauge.

http://www.ctmrs.com/prosnap.asp

[TheWire]

If I'm reading the consensus here correctly, a ribbed metal roof with exposed fasteners is just as reliable as a concealed fastener standing seam roof all other things being equal.  I have to price it out, but I think think the ribbed roofing will be cheaper than the stand seem.

Also,  I'm seeing a range of 28ga to 22ga steel.  Some of the steel is made to span purlins and support weight in the gaps between purlins.  With a full OSB deck underneath, does anyone see a problem with the 28ga.  Most 28ga I see still has a high rating for impact and it wouldn't need to support weight when its sitting on an OSB roof deck.

   

[glenn kangiser]

No problem - 26 to 29 gauge would all work well.  Ribbed will be easier to work with - less labor also from what an installer told me about the standing seam pan deck w/concealed fasteners.

[TheWire]

The metal roofing company's install manual says the gasketed screws can be installed on top of the rib or in the flat surface of the panel between the ribs.  On the flat would seem to keep the the pressure on the gasket because it can't flex, but on the top would keep the holes out of the area where most of the water will run.  Can anyone provide feedback on which way to go.

Thank you,

Jerry

[Redoverfarm]

Jerry I placed mine in the flats.  That is what the Contractor was told by the manufacturer of my roofing material for their warranty.

Here is a couple of sites that might interest you or assist in your decission.

http://ms101.mysearch.com/search/GGmain.jhtml?st=bar&searchfor=metal+roof

[glenn kangiser]

In the flat and not on any small ribs (beside or between small ribs to prevent dimples) to fasten the sheets to the purlins or roof sheathing.  On top of the rib but not in any drip grooves or siphon breaker grooves  if they are there to stitch the edges of the sheets together and make more secure in higher wind areas.

[MountainDon]

The metal roofing company's install manual says the gasketed screws can be installed on top of the rib or in the flat surface of the panel between the ribs.  On the flat would seem to keep the the pressure on the gasket because it can't flex, but on the top would keep the holes out of the area where most of the water will run.  Can anyone provide feedback on which way to go.

Thank you,

Jerry

As Glenn indicated using screws through the high rib where the edges of the panels meet is good to prevent a strong wind from grabbing that edge. That's what the roofers around here do. Everything else on the flat.

Lighter gauge metal may show any imperfections in the sheathing more liley than heavier. We went for the 26 ga., also beacuse it had a better hail rating.

[Redoverfarm]

Glad you made it back on the net Don

Jerry I just made a simple purchase from Harbor Freight that you might be interested in if you are contimplating putting your own metal roof on.  It is a nibbler that runs off of compressor.  At $29 or so and extra cutting die for $6 is is well worth the money.  Even 28 ga is hard to cut with a pair of snips or a metal blade.  This leaves a nice clean edge.  It is rated down to 16 ga metal.  Even if you measure exactly and order to exact length you will almost always have to make some cuts. 

[Redoverfarm]

Jerry I was wrong about the price on the nibbler. It was only $19.99 rather than $29.  That's only about the third time in mine life I have been wrong    We won't got into the others.

[glenn kangiser]

One was admitting you were wrong, John.  There should have been some way around that. hmm

[TheWire]

John,

Thanks for the lead on the nibbler.  Unfortunately compressed air by me is a challenge, let alone the 17.5 CFM the nibbler wants.  I have a 3500watt generator which starts my 1.5 hp compressor OK but the compressor kicks out on thermal overload after 5-10 minutes.  However Harbor Freight also has a nibbler that connects to a drill, cordless in my case, for $40 or a 120VAC self contained model for $50.  I'll be looking at those on my next trip to HF.