I've been posting update to ABPW on my "baby barn" timberframe project. I'm inclined to go with a metal roof and I'm looking for some opinions the various technoligies.
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stuff looks pretty simple to install, but the idea of screwuing through the roof surface to attach it just does not seem right to me. It seems to fly in the face of conventional "cover the fasteners" wisdom. Can those screws with rubber gaskets really hold up long term?
The alternative seems to be
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which is attached by screws or nails on a tab which is covered by the next coarse of roofing. Unfortunately, it's considerably more expensive, especially when you need to buy a specialty trim piece for every single edge of start, stop, endwall, facia, gable. ridge etc. All of the original (old) standing seam metal roofs in this area have much less complicated edge treatment, like the edge is just bent over to form the drip-edge.
The application is an unheated outbuilding (big shed).
Is there a reasonablly priced (by that, I mean up to twice the price of asphalt shingle) metal roof technology that does not require puncturing the roof surface and/or significant retooling?
Steve I have a metal roof on my house. It is an Alcoa aluminum Cedar Shake shingle metal roof and I am really happy with it. I have had it on my house for 15 years now with no problems except where a bullet hole formed a leak. It was easily patched 12 years ago. No fasteners are exposed.
Over my deck I have galvanized corrugated sheep metal. Great application and I used rubber washered screws to attach the panels. I probably did not attach all the fasteners perfectly as occasionally I have a small drip leak. IMHO, these exposed fasteners are going to eventually leak. If a leak is going to be a problem, go with the least likely to leak, the style that has no exposed fasteners.
Typically the metal roof is a lifetime roof, don't cut corners.
Yes they will hold up long term for that type of roof. But the real question is 'what do you consider long term?'. The biggest mistake most people make in installing this type of roof is driving the nail/screw in too deep. The rubber need to only be held down firmly, not conpressed too much. They will last for several years. I have seen barns that the rubber is still in good shape after being up in the sun and weather for 20/30 years. The only thing I might suggest you be care of nowadays is the quality of the rubber. Don't buy the cheapest thing out there. Make sure the rubber is of good quality.
"clips hidden by the rib" technique so that no fasteners are exposed to the weather. Like Leon said, "lifetime", and keep your finger off the trigger. Tom
Panel roof systems are great if you have the panels installed correctly and use the correct trim pieces. While a lot of folks just buy the panels and start cutting and screwing, a few more dollars for the correct trim and starte pieces make a big difference.
We have installed panel systems (there are a ton of manufacturers!) from different makers, but they are all pretty much the same. This one seems to have a nicer finish than most. It looks similar to the Kynar
500 that goes on the better metal panels and coil stock for standing seam roofing.
As you see, the manufacturer says to screw in the flats. It is easier.... but not better. I now install these products by screwing it down through the ribs.
Think about it for a second. Where does all the water travel? On top of the ribs or in the flats? In my conversation with one of the manufacturers of "J " and "M" panels, he agreed, but they found it too hard to control the screw guns and since most folks over drive the screws anyway, overdriving on the rib creases the panel.
My method takes longer but I really like the results. I lay out the panels on sawhorses and pre-drill the holes. That way my anal retentive eyeball looks at the lines of screws and they are all in the same place and the lines are nice and straight.
When the rubber gasket fails, and it will (we do good work "encapsulating" the head of these grommet headed screws after they do), the water will not run into the roof as it would if the screw was on the flat. That being said, if it is a tight bid, I install like everyone else for the sake of time savings and haven't had problems with the two or three full roofs we have put on.
Don't forget to put down some really good underlayment, and certainly don't forget ridge venting.
asphalt shingle) metal roof technology that >does not require puncturing the
All metal roofs, and as far as I know all roofs period require attachment to the roof system, either to screeds or direct nail/screw to the deck.
Metal roofs can be permanent, but will require maintenance (pull out the old rusty, leaking screw and replace or enscapsulate the heads) down the road. If you are going to live there a long time, it could be worth the investment. OTOH, with proper slope and venting, I would probably go with asphalt shingle at this point as the metal panel roofs don't seem to hold up as well as they used to. I am repairing metal roofs that have damage (from highly acidic oak leaves) on them that are only a few years old.
On the other hand here in South Texas I see properly vented asphalt 20 year rated roofs that are in good shape 15 years down the road. Bang for the buck, asphalt is hard to beat. It is easy to apply, usually doesn't require maintenance, and easy to replace. And you get your significant savings up front.
Here, in the humid pacific northwest, the biggest problem we have with wood shake and asphalt roofs is moss. Enough moss will shorten the life of these roofs. One of the selling points of a metal roof here is that moss will not grow on it.
I have installed roll asphalt on a number of sheds. It is quick and fast. I go nuts and layer it at least twice if not three times. I also double the tarpaper underneath it as well. Then I seal all the nails. It would look like crap on a house. But for a shed, I can get away with it.
I am curious. Do Texas hailstorms damage metal roofs?
I appreciate you comments. i have a couple followup questions below:
My local yard suggested using panels over standard (vanilla drip-edge) is there any functional (as opposed to aesthetic) problem with that?
Thanks, That's a good tip
Does a good quality variable clutch drill solve that prblem or do you need more coptrol than that?
I read that pencil marks are a no-no as they wil corode the surface. What to you use to mark your drilling locations?
Should I expect that in 5 years or 30?
Could you explain your encapsulation process?
I was planning on using a 15# felt over rough-cut pine planks. How important would you think it would be to send those boards through the planer to even up andy subtle differences? BTW, the deking will be oriented ridge to soffit rather than gable to gable.
I'll vent through the coupola. I assume that will be enough venting for Northern NY.
I do have a monsterous english oak very close by. I would think, however that with a 12/12 pitch, leaves would simply not stay on the roof very long. Do you concur?
shake and asphalt roofs is moss. >Enough moss will shorten the life of these
grow on it.
Absolutely. While we don't have the precipitation you have by any means or the constant humidity, 80%+ humidity days are not uncommon. In Houston where Swing and Leon (and my sister!) live, relative humidity stays around 160 - 180%.
But for those with large trees, fungus and mold are always a consideration, unless you live in Arizona. When I have a house that has trees that shade it a lot, I know it can easily grow mold. In this case I include an alternate material bid of "FR" rated shingles, or "fungus resistant".
It will beat them to pieces, causing tremendous loss of investment. We have had hail this year quite a bit, with the largest sizes I can recall as being baseball sized. Two years ago, grapefruit sized hail swept through a couple of car dealeships and literally smashed cars to pieces.
Metal roof, patio covers, cars... nothing is safe when that stuff hits. Thankfully, the season is short, and most of the time we get pea to bb sized hail.
drip-edge) is there any functional (as opposed to >aesthetic) problem with that?
To me, yes. Standard drip edge, large drip edge, DL, whatever you buy will almost certainly be 29 ga. electrogalvanized zinc steel. Someway, they have found a method to make the zinc so thin (or maybe the quality of plating is so bad), that it will actually flash off. We are now seeing exposed zinc metal flashings rust in just a few years. That NEVER, EVER used to happen. I have installed many chimeny saddles, open flashing details etc., that I left unpainted and exposed. No more. Every piece of zinc metal is covered due to corrosion issues.
If you are going to buy this package from a dealer, they will have the recommended starter strips, hold downs, eave strips, etc. It will have not only the galvanized finish, but it should have the primed, polyurethane coating on it as well. You should be aware (although I think it is a mild load of baloney) that some manufacturers will not honor the coating warranty where you use trims and flashings by others. They want to ensure total system compaitibility as well as sell you more product. For a really good look at the reason why you wouldn't want to use lumberyard stuff for the long term, take a look at this coating layout:
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can see the coatings. And I like the fact that it is coated on both sides in case you get condensation.
but not better. I now install these >>products by screwing it down through the ribs.
more coptrol than that?
Spend the money and buy a good screwgun. I have a couple of Hitachis that I only paid about $75 for, and they are great. IME, clutches in drills are not nearly as accurate as the clutches in a dedicated screw gun. Just don't forget to predrill your metal and you will be fine.
you use to mark your drilling locations?
Never heard that one before. Why would graphite cause rust? I actually use a blue Sharpie on the metal, and mark it upside down. When you drill your panels, flip them upside down and mark and drill the backside. No marks will show. You can drill about 5 at a time pretty easiliy. Make sure you use SHARP drill bits. Go to Grainger or similar and buy a couple of packs of jobber bits, and when they are dull, keep them to resharpen or toss.
Dull bits leave jagged holes that will cut the washers on the screws.
Depends. Don't buy lumberyard screws unless they are good quality. I buy mine from the roofing supply house here, and they have neoprene washers instead of rubber, and they are zinc plated, not painted.
See if you can get the kind of screws that have a cup washer on them as they will compress, but protect the washer a little more than just a flat washer.
I have seen screws that haven't leaked in 10 - 15 years, and some that leak in as little as 5.
after they do)
You can make some money with this one. Tighten the screw if it is loose. Take a good quality elastomeric UV resistant caulk like NP1, and put a wad on top of the screw head. Work it in a circular motion around the screw head, getting the sealer mashed onto the screw as well as the deck, and leave it looking like a small Hershey's kiss when finished.
would you think it would be to send >those boards through the planer to even
rather than gable to gable.
I believe the product you selected called out 30# felt. 30# is thicker, has more asphalt, and will stay flexible longer. It will also seal around the screws better. When we do low slope ashpalt roofing (2 1/2 in twelve) we use two layers of 30# for the additional underlayment. Go with the manufacturer on this one.
I wouldn't worry about the uneven wood if it isn't anything more than
1/8". I would worry about the orientation of the decking. Not only is that a poor way to deck even with a crossed substrate to nail, but your roof structure will not be nearly as strong as if framed with the decking material at ninety degrees to the framing. Unless it is properly decked on top of the pine, that wouldn't make code here. (Nor should it).
Depends on the size of the roof. Automatically, I would say no. Venting is not just the simple removal of accumulated heat, but the dissapation of moisture. It has been proven over and over again that greater distribution of the venting like full ridge application, is many time more efficient than a large hole in one area (say a cuppola on one end or the other, or just in the center).
Also, since you are in NY where they have snow (!!) and ice, I would make sure along my eaves I ran >at least< one 36" course of ice and water shield (the self adhering, non granulated kind) around the eaves. This area will be the hardest hit by ice, and the ice will work on those screw heads like you won't believe. However, the ice and water will seal around the screw shanks and they will stay sealed. BTW, the ice and water goes on the deck, under the underlayment.
that with a 12/12 pitch, leaves would simply >not stay on the roof very long.
Absolutely. Those leaves would have to be covered with bubblegum to stay on 12/12 metal roofing.
A couple more thoughts. Good metal roofing requires almost no sealant. All joints are water deflecting through correct flashing procedures. The installation pdf on that manufacturers site has some great detailed drawings for flashing details.
If you cut or trim the sheets, make sure your cuts are covered and that the factory edges are the only ones exposed. Don't use a grit blade in a circular saw. Buy yourself a good set of tin snips and a set of aviation style shears. You will find these to be the most valuable tools you own during the installation process. Straighter, cleaner, easier and more accurate cuts are their own reward.
I usually leave about 1 1/2" overhang over the eaves, and use the manufacturer's product for gable ends.
Only walk on the roof with soft soled CLEAN shoes. No workboots! With 12/12 pitch, you should pull the plastic film coating (if any) off before you screw it down. Handle the product carefully as deep scratches will rust.
Never use silicone (no matter what the tube says) or latex products (anything that says it is washable) on the metal. It needs to be solvent based, and you should see that on the tube. After all these years, I only use NP1, a Sonneborn product on metal roofs and flashings.
Whew... good luck!
I hope you drop a note and let us know how it turned out.
LOL, 2 years ago my insurance company offered to lower my rates by 10%.. wooooo, If I would only require them to repair my metal roof it it leaked after a storm. I took a big PASS on that offer. I paid big bucks for a nice looking lifetime roof. I don't want it to look like crap because I wanted to save $80 per year.
Code takes all the fun out of napkin engineering :-)
Fret not; the decking will be at 90 degrees to the framing. It's a timber-framed barn, not a twoba-framed structure. The main rafters are connected with 4x4 (the whole 4, not wussy 3.5" dressed things) structural perlins to which the decking can be nailed.
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