Metal Roofs

[Steve_B]

Love the look of a metal roof for the clean lines and color...

I see a lot of them on the site here... do you guys use roofing companies to buy the roofs or are you buying just sheet metal ( corrugated or such ) and using that to lay down on the roof?

Is the metal roof just attached to the roof sheathing or are there other layers in between?

[ColchesterCabin]

For me personally I am going to use a local company here to provide my metal, fasteners and such, tey will deliver to my job site for no charge. But everyone has a different plan as you'll notice here on the forum.

P.S.
Welcome 

[alex trent]

I did mine and was not a big deal.  My roof is 4/12 pitch which makes it a bit easier.  Some rule to follow on installation and do them.  I read a lot of horror stories/warning about metal....mine has had one minor screw leak in a hurricane type downpour.

[offthegridcortland]

I used a local building supply for the metal (aluminum) and the fasteners.  Rafters then ply then heavy felt then the aluminum attached with self-piercing, hex-head roofing screws with a neoprene washer.  Really couldn't be easier.  I had a 12/12 roof so to me, dealing with a light weight single sheet seemed easier than continually moving about, up and down ladder to move laterally to put up each row of shingles.  Another nice thing is the absence of roofing nails which have a way of finding their way into the bottom of feet for years.  Sheds snow, reflects heat- love it.  I'll rty to find a picture of the contraption I built for roof work on a 12/12 roof.   

[offthegridcortland]

I should have noted that I ran a bead of caulk at the ridged seam between panels as well as at the ridge cap.  Cutting aluminum's a snap too- just reverse the blade on your circular saw and get to cutting.  Make sure you use ear protection- it makes a racket.

[alex trent]

I ran a bead of silicone vertically between panels.

On the up and down overlap, do not be stingy.  Check the table for the length of sheet needed to the seam to prevent water backing up in heavy rains. More important with lower pitch.

Important too is to run the screws in perpendicular to the sheet.  Tendency is to move closer to perpendicular to ground if you do not think about it. This means an uneven seal on the washer and a leak. That is what happened to my one screw that had a leak.

[Steve_B]

I should have noted that I ran a bead of caulk at the ridged seam between panels as well as at the ridge cap.  Cutting aluminum's a snap too- just reverse the blade on your circular saw and get to cutting.  Make sure you use ear protection- it makes a racket.

Can I ask what gauge sheet aluminum and how big in size were the sheets?

How many fasteners per sheet did you use?

Did you paint it?

[offthegridcortland]

Steve-  It's been awhile, but 24 gauge sounds about right.  I believe it came in 3' widths or maybe 37'' to account for the overlap.  I think less is more with fasteners.  I am loathe to put a hole in a perfectly good roof.  I did a line every four feet or so.  You should snap a line parallel to the ridge because you will be looking at those screws forever and they look like heck when they aren't lined up.  I'm sure the manufacturer has a guide.  You can put a line under the ridge too.  I didn't paint and would think you'd loose more than you'd gain.  I like the slickness of a metal roof, same reason I liked a 12/12 roof- everything sheds and sheds fast so things like snow loads are almost academic.  Wind, of course, is not.  Water, well everything really, wants to move straight down, so the steeper the angle, the less time it has to find problems.  A steeper roof is harder to work on, whether initially or repair, but I think will need less repair over time.  I also think the steeper roof looks more classic/ timeless.  If I had loads of money I'd use copper and not even my grandkids would worry about it.

[MushCreek]

I pre-drill the sheets. Stack them neatly, and measure off where to put the holes, and then drill all the way through the stack. Your screws will be perfectly aligned. Your best bet is to install per the manufacturer's instructions.

I've wondered about using a peel and stick underlayment for mine- they tend to seal well around the screws, so if a gasket does leak, the water won't get any farther. Adds to the cost, though. Make sure that whatever barrier you use under the metal is designed for metal roofing.

I'm going with the old traditional 5V rib, in Galvalume finish. My barn is Galvalume, and the missus wants them to match. That saves $50 a square right there (the cost of the underlayment).

[alex trent]

Pre-drilling would make it a lot easier...I was chicken to do it.

On the v crimp...screws go on the flat. Might sound counterintuitive, but on the ridge will distort the ridge with just a little screw in error and you have a leak.  Follow the manufacturer's reccos.

I used 24 but am only on purlins and no underlayment here.

I got colored roofing. Painted some on another building and be sure you pre[ it right or you will have a mess.  Wash with steel wool and detergent and then vinegar to sit for an hour. Rinse it well.  There is special self priming pain and it works well...two coats needed.

[CjAl]

do you screw on the top of the ribs or on the flats? i would think you screw to the low flat parts but on the overlap you almost have to screw to the top of the rib where the panels overlap

[CjAl]

guess i was a minute late on that question

[Steve_B]

Can anyone point me to a website that sells metal roofing online to get an idea and show the misses?

[alex trent]

Here is a good link on roofs...good diagrams of nailing and other stuff.  Yes, you do have to screw on rib on the edge...i put a bead of silicone under it as insurance and was extra careful not to dent the rib..actually they are pretty strong so you have to be really not thinking to crush one.


The other link was wrong one..this is it.

http://www.bestbuymetals.com/pdf/r-panel-installation-guide.pdf

There are some shots of my roof..Nicaragua Mtn Cabi...on here.  I also have seen a couple of other roofs on here, including a 12/12..will see if I can find...shots were better than mine.

[alex trent]

Here is another good site with lost of info..

Page 10 has the required length to prevent ryan from backing up under the panels.

Note, this is 4" an hour....big time rain.

http://www.fabral.com/assets/media/downloads/details-postframe.pdf

Another note..

Tendency is to put a lot of screws in.  Every one is a potential leak so don't.  if you follow instructions it will hold on with the recommended about.

[rdpecken]

We bought ours from a local distributor Absolute Steel http://www.metalroofingsource.com/ in Tempe, Az. We told them the lengths, and the supplier cuts them to length for you.  The company helped us spec out how many fasteners, trim pieces, etc we would need.  Then they ordered everything and we picked it up a week or two later.

The type that we chose has hidden fasteners, so all screws are underneath the roofing.  You screw down one side, and the next panel (or trim piece) covers the screws.  No leaks in the five years since we installed them.  The metal roofing is much easier to install than the asphalt composition shingles.  I had help (family) with the steep part, but easily did the shallow part myself, and could have done the steep part myself, as well.  I would never use shingles again.

Have fun!




Randy

[Steve_B]

Metal roofs just give that perfect finishing touch and clean lines...

They do have some nice stuff at http://www.metalroofingsource.com/

They even have a color visualizer to see what it looks like before hand with all the colors they offer

Thank you for that link!

[rick91351]

My shed roof shop up at the ranch.  Engineered trusses at a 6/12 pitch and roof was was sheeted with OSB due to 130 lbs snow load requirements.




These panels were 16 feet and 22 gauge if I remember correctly.  They actually are the same pattern as rdpecken's green which is a color we almost did.  The metal came with screws and mounting requirements from a metal roofing manufacture in Boise.  We had a whole spectrum of colors to choose from.  We chose this darker color to help aid shedding the snow.  We only have about two months max of hot up there.  It is surprising with just a little of the dark showing through the snow how it can effect the snows sliding off during the day.     

Handy roofing gauge guide

29 gauge.....0.0145"
26 gauge.....0.0185"
24 gauge.....0.0230"
22 gauge.....0.0290"
16 gauge.....0.0540"
15 gauge.....0.0620"
14 gauge.....0.0690"
13 gauge.....0.0830"
12 gauge.....0.0940"

POST SCRIPT!!

OOPPPSSS!!! JUST CHECKED THE PAPER WORK WAS 24 GAUGE!!

[MountainDon]

I'm not an expert metal roofer. But I believe silicone sealants are a poor match for use with metal roofs. Silicone caulks and sealants usually have a pronounced vinegar odor (acetic acid). It's the acid, not the small that can be a worry. The metal roofing caulks I have used were a polymer or some kind and had very little odor. Apparantly they are more friendly to metals.  We used one made by Titbond.

Note that windshield repair / replaement shops use a latex sealant for that reason. At least the shop I've used does and told me it was because silicones can lead to corrosion around a car windshield.


24 gauge is used more for commercial roofs IIRC. 24 gauge makes a solid home roof... it's the minimum gauge that would give us the homeowner insurance discount. 29 gauge is common with on the shelf orange and blue big box stores where we live. But they can order 26 gauge.

Many screw leaks originate with overtightening the screw. There is a different screw for securing metal to metal edges; larger diameter threads and shorter threads.

We bought our metal roofs from http://www.metalmarts.com/index.php   They serve LA, TX, NM,.... maybe more.

Our panels covered 36" width and were ordered to desired length from their factory.

[alex trent]

There is special silicone for metals.  Try to get that or use butyl tape, which is what is recommended.

If you cannot...here is what i have been told and read.

It is unlikely that the slightly acidic content of the sealer will damage or rust the metal. First, the acid content is gone is a day.  Second, the metal is coated..and if you have painted, it has another layer. Acid rain is more of a threat, so if you cannot get the "special stuff", use silicone....it is better than taking the leak risk.

I'll try to hunt up the piece I read on this.  I looked it up when doing mine as I read what you just said and it worried me.

[Don_P]

I've seen rusting related to silicone on galvanized roofing several times. I don't think I've ever seen it used on a painted roof. I use NP-1 polybutyl when I'm not using what came from the supplier, this is what the site formed metal roof crew uses here as well, the HVAC suppliers usually have it also.

I used to order from Fabral and was pleased but we now have 2 local companies that manufacture roofing and trims and carry all the tools and supplies. I use them for a lot of flashings on the house as well, they can do heavy guage color matched window caps, Z flashings, etc.

[alex trent]

It's interesting that down here in the land of metal roofs, other than the sheets, the ancillary supplies are not to be found. Like tape or the sealer you mention. Even the screws are suspect..the coating looks thin and the gaskets...hard to tell.  I brought mine in.

We have no ridge caps...have to make your own from a roll of tin. That is not too bad as we do not need to seal out the cold and the space between the ridges and the cap ventilates a bit.

Make it work with what you have and don't panic too much about what you cannot get is the byword.

[MountainDon]

Make it work with what you have and don't panic too much about what you cannot get is the byword.

I disagree.

Unless there is no correct choice available with reasonable time and cost, then the correct "thing" is the "thing" that should be used. To say that whatever is at hand will do, can mean re-doing something down the road or perhaps a failure that is both inconvenient and disastrous.

I'm replacing a cylinder head gasket.... the manufacturer's procedure calls for use of a thread sealant (a specific Locktite product, or similar) on one bolt and one bolt only. I could get myself, or some future mechanic, into difficulties by either omitting the sealant or by using the sealant on all the bolts. .... I know, that's perhaps not the same as how to properly install a metal roof.

I believe we here at the Country Plans Forum do try to recommend and endorse methods that are best suited for the best longevity, safety, etc, etc. We don't always succeed, but it is my goal to try as hard as possible to do things in a "shipshape" manner. That was why I took a moment to pass along the information I have on silicone caulks and metals. I'm not mentioning those facts because I want anybody to tear down and redo what they have done. I mention those facts because I would like anyone reading this to be better informed, to be able to decide what they want to do on their future projects.

To be more correct I should modify my comment on silicone caulks to state that some silicone caulks and sealants have the ability to cause corrosion on some metals. It is true that there are silicone caulks that are formulated with less acetic acid in them than in years past. Manufacturers may try to formulate the silicone caulks with just enough acetic acid to effect a 100% cure, no excess. However, if the mix is slightly short then the product may not perform as desired. So it is really a case of know the characteristics of the products you are thinking of using. In some cases this may require a rethink if optimal results are desired.

Alex, you noted that the roofing screws readily available to you down there are suspect. I note that information that promotes a lackadaisical attitude to materials or techniques is suspect.

Some folks agree wholeheartedly with you and say it doesn't really matter. Okay. Fine. Then again there are some folks who may be glad to hear of potential metal - silicone caulk issues.

BTW, silicone caulks cure by attracting moisture. They do not dry to become "set". This is why they do not shrink when cured. In a low humidity environment it can help speed the cure by using a spray bottle to create some water mist. Water is also an enemy of some metals.

[alex trent]

Well, I don't disagree with you.  But everything has to be put in perspective. ...and there is no "one correct thing"  or at least rarely so. There are options and not all are A1, but many will suffice with no sacrifice in safety, etc.  This particular issue is not a critical structural issue..at least way down the list.

So..when you cannot get the exact right product, you have to look around for alternatives.  One was not to use silicone at all.  That is not the end f the world in this roof job. The other is to research it a bit and see just how much of a problem it really is. In looking on line and talking to two people here and in Canada ( he does metal buildings), they rated it very low on the scale of "this is going to be a problem in the future" 

What I found was alternatives that didn't look satisfactory , so I went with what I considered the next best option...silicone that is said to have a low acid content.   Cannot even smell  it.  Moreover my tin is painted. Judgement call on my part and that is much of what life is all about.  It is not all in the IRC.

Would I have used the pure "metal" silicone of I could..yep.  Did I really need to...nope.

The first part of my post was actually not about that, but to correct a misperception that you may have fostered that there is no silicone that is good to use.  Not true, there are several brands made just for that. I think the readers are much better off with the options  and some other reasoned thoughts, not just one "this is the way it is" statement.  Like you, I was just passing on my information about silicone and metal roofs.

[JRR]

I have been using this Loctite product: http://www.loctiteproducts.com/p/pl_seal_rf/overview/Loctite-PL-Polyurethane-Roof-&-Flashing-Sealant.htm

A bit pricey.  I wish it were available in the larger caulk tubes.  Does anyone have a better/less costly alternative?