Replies

1. 
   brownbagg | Feb 23, 2004 06:51am | #1

   here mine on a 1200 sq ft house. metal on 3/4 plywood with tar paper. contius ridge vent. Do not screw the humps, screw the flats. I did it myself, just makesure your roof is square, and yes you can istall on top of shingles, everybody does.

1. 
   sleddriver | Feb 23, 2004 08:34pm | #4

   When I clicked on your photo, I just saw a blank space. I'll have to check on my email protection software if others can see it.

   One thing I learned long ago is never assume anything on my house is square. I thought of laying out as large a right triangle on the roof as possible to get the first sheet going straight and then let the others follow.

   Thanks for your reply

2. 
   Piffin | Feb 23, 2004 07:08am | #2

   Whew!

   You've made up for not posting a word for awhile.

   ;)

   Use the 1x4's and attach them on the rafters. Since you are concerned about loading, put them at 16"oc. If you lay directly on the asphalt shingles, the movement of the thermal expansion will abrade the metal from the back side.

   The 1x4s will also give you what we call a cold roof with extra ventilation chamber. The manufactureres have charts for fastener schedule layouts for different wind load and snow loads. IMO, If you go 16" oc and a hundred fasteners per square, a tornado will be lifting the whole house before it tears this one off.

   I predrill the stack on the ground too. I drill slightly oversize of the shank of the screw so it can deal with the thermal expansion. Predrilling makes it all easier to install and keeps the holes lined up neatly. Never seen the burring you report. Maybe drilling several sheets at a time eliminates that.

   use the larger diameter screws with the 5/16" head. Too many failures with the 1/4"

   I would not ever use the ridges instead of the flats. Especially with the high winds in Texas. Screwing in on ridge tight enough to compress the neoprene washer will overcompress the ridge and lift the flat pan so the wind can riffle it and that will definitely cause hole tearout action.

    

    

   Welcome to the
   Taunton University of Knowledge FHB Campus at Breaktime.
    where ...
   Excellence is its own reward!

1. 
   sleddriver | Feb 23, 2004 08:54pm | #5

   Yeah . . . I did.  Ooops . . . didn't realize it until I saw the 'truncated' note! In my effort to fully describe my situation I wrote a whole article for an intro!

   I like 16"oc . . that'd give me 12-1/2" of free space. I also need to remember to put additional wood where I'll be remounting the solar collectors, so the weight will be transfered directly to the rafters instead of flexing the metal. I told the panel manuf. my concern about the remaining granules abrading the backside of the metal coating, possibly shortening the life and he said it wasn't a problem. . . .hmmm. Then I thought I would lay down some underlayment on top of the shingles to smooth the surface.

   I've never lost shingles due to high winds in the 22 years I've lived here. I'm not on a ridge, but not down in a valley either. . . . hard to describe. Course, now that I've typed that I expect to wake up one morning in the next two weeks and find my yard littered with old shingles! Good point though . . . I have to think of a whole panel levitating now.

   I like the idea of predrilling on the ground . . .read about it in the archives. I have nearly two dozen screws in all diameters, lengths, etc. . . been told to use the larger diameter ones . . #12 instead of common #9's. Wish I could find something with a coarser thread. Which screw do you use? I've looked at Buildex's and SFS Intec's Woodgrip screws so far.

   Thanks for the reply

3. 
   DavidxDoud | Feb 23, 2004 07:12am | #3

   I'll relate my experiences and be interested to read others...

   first,  you should find no shortage of verbage if you go to advanced search and type in 'metal roof' - so you can spend some more hours winnowing thru information...

   next,  I would not consider putting sheet metal directly on top of your shingles - two reasons - 1.  it is not a flat surface and you will deform the metal as the screws are torked,  perhaps not much of a consideration if you go thru the ridges,  but that brings reason 2.  1/2" plywood is not adequate to hold the screws - and running screws down the rafters is not adequate or a recommended pattern -

   which means you fur the roof - I don't like 1X4"s - cheap and soft - one strategy would be to screw 2X4"s on 16" centers,  then stagger the screw pattern (with 1 1/4" screws)  @32" between ribs - this would answer a lot of your concerns regarding support,  etc,  and with some forethought,  get you clean,  solid perimeter detailing.  And securing the perimeter is the most important part of roof,  most problems I see are wind related,  getting under the metal and flapping or lifting it off under severe conditions - ya don't have any of those in Texas,  do ya?

   I've always screwed thru the flats with self tapping screws and on the 10 or so metal roofs I have done,  there is one small area (on my own house!) where I have trouble keeping the screws tight - I haven't analyzed why that is - Last fall I inspected a roof I did in '82 and found no loosened screws - - I believe Piffen mentioned in another thread that he replaced the 1/4" screws with a larger diameter and cured the loosening problems...

   valleys are the challenge with ribbed roofing,  and I'd suggest you work closely with your supplier on the details..

   good luck

1. 
   sleddriver | Feb 23, 2004 09:08pm | #6

   Yeah there is lots to read in the archives. Wish there was a way to search just the beginning of a thread. . . maybe there is and I have yet to figure it out.

   A whole 2x4, eh? Seems a bit thick to me . . . but I hadn't thought of it. I can see how any metal vibrating due to wind blowing under the edges of it or even over it could really tear it up quickly.

   I'm curious which screws you've found worked best for you? I agree a tiny #9 doesn't have much bite unless installed in alot of solid wood. I like the idea of using a #12 with a larger head.

   Fortunately, my three valleys are very short . . . though one awkwardly dumps out close to the edge of the roof.

   Thanks for reading my novel & replying.

1. 
   DavidxDoud | Feb 24, 2004 03:03am | #9

   all screws are not created equal - here's a pict of two 1 1/2" gasketed screws - examine the washer and you'll see one has a nice deep washer with a thick gasket vs the nearly flat washer and thin gasket -

   the other is the bag information - if you go  larger gauge,   ya gotta drill holes -

   whoever mentioned getting someone else to do the job has a point,  but it's not rocket science and if you are capable and safe at every job you do,  then you can do this job - new set of three-tabs looks better all the time,  doesn't it?

1. 
   sleddriver | Feb 28, 2004 05:57am | #11

   I found a great screw . . . . Oooops . . . .didn't mean it like that! Here's the details:  It's made by Buildex, 5/16" AF HWH head with a bonded washer, 14/10 by 1-1/2" long with a wood drill point, item #  1526000. It doesn't show up in their on-line catalog and the woman at HQ said they show zero in stock.  Said she found it in a 'metal building fold out'. None of the local Buildex dealers I tried had ever seen it before. . . . nuts.

   I've noticed that the Buildex screws have large thin rubber washers while the Intec versions have thicker, smaller ones with a different style metal washer above it. Wonder why the difference? When I called each manufacturer, they couldn't tell me. I'm guessing there's a difference in torque required to seat each one. Any ideas?

   In Texas, roofing contractors don't even need a license . . . not yet.

   Yeah . . . three-tabs are looking better all the time . .

2. 
   4Lorn2 | Feb 28, 2004 08:41am | #14

   I share your concerns, I have a metal roofing project coming up, but why would a #9 screw in half inch ply hold less than a roofing nail in half inch ply. I'm no roofer but I know that a screw has several times the withdrawal resistance than a nail.

   Give it a try. Screw a nail in to a piece of plywood leaving the head out a good bit. Hammer in a roofing nail also leaving the head out a bit. Try removing each with a claw hammer or pry bar.

   Once won a bet comparing a 2" deck screw to a 16d nail. A crowbar pulled the nail easily. The screw resisted to the point the carpenter had to put all his weight on the bar. The screw finally broke under tension. I think this was more about the crowbar bending the screw back and forth during several attempts.

   To my mind runners are only as good as their attachment method. Their main value would be to smooth out any unevenness in the roof to make it more a single plane.

1. 
   DavidxDoud | Feb 28, 2004 04:15pm | #15

    but why would a #9 screw in half inch ply hold less than a roofing nail in half inch ply

   the answer,  of course,  is that it doesn't,  as your field experiment showed - - the rest of the story is that you use 4 roofing nails per shingle and how many shingles per square? (I dunno,  but several)  so some hundreds of nails per square which in aggregate hold adequately (most of the time) -

   the sheet metal will only have a few screws per square so it's necessary that they hold much better,  at which time the substrate becomes the limiting factor. (run that field experiment with  two screws,  one just screwed in like your example above,  one screwed in and then tap the head back and forth a few hundred times to simulate the metal expanding and contracting of the course of time)

   guess you could use roofing nails in sheetmetal at a similar rate as shingles and hold it down,  but that would probably negate some of the sheet metals water shedding capabilities ;>)

2. 
   brownbagg | Feb 28, 2004 04:46pm | #16

   think about this. If you do not screw it down, how are you going to fatern it. Maybe by welding then, plywood does not weld too good. so it either screws are nails. period.

3. 
   Piffin | Feb 28, 2004 05:00pm | #18

   To answer your Q about pullout resistence in 1/2 ply -

   I'll make up some figures here for sake of comparison. Let's say that the screw takes a thousand pounds of force to pull it out and the nail only takes 400#.

   But you use about one screw per sq ft. With three tabs and nails, you'll have three or four nails in that same sq ft of surface exposed to wind.

    

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

4. 
   CombatRescue | Feb 29, 2004 01:13am | #19

   This type of metal roofing is very common down here in Florida.  Most of it is a 5V crimp - sheets are 2ft wide with double V crimps on the edges and a single in the middle.

   As you can probably guess, we have a pretty strict hurricane code down here - buildings are now required to be able to withstand 120mph winds (in my area).  The code to meet this requirement is 1/2 plywood roof sheathing (not OSB).  However, the sheathing is nailed at 6" intervals on the edges and 8" in the body.  Also, all edges that don't fall on a rafter must be backed by 2X material.

   Virtually all the roofs here are screwed through through the crimps, as opposed to the flats.  The main reason for this, I've been told, is that water intrusion is much less likely than on the flat if the screw should back out or loosen over time, since the hole is at the peak of the crimp.   We get a lot of rain here (monthly average ranges from 2 1/2" to 7), so water-tightness is a big issue.

   As for the wind, you can meet code here with 28 gauge or thicker stock.  The fasteners are #9 or #10 screws depending on the manufacturer, but I'd use thicker ones (like #12).  The fastening schedule typically calls for 4-6" spacing at the edges and 8-12" in the body depending on the hurricane zone you're in and your exposure.  The edge spacing is critical, as this is what prevents the wind from getting under your roof.  Proper fastener spacing for your windload is more important that whether you put your fasteners on the flats or crimps.  Most manufacturers here recommend the crimps, but have alternate patterns for the flats.  In general, fasteners in the flats should be placed within an inch of a crimp (as the crimps are what provide the sheet rigidity)- not in the middle of the flat.  At least that's the requirement down here.

   So based on all this, I wouldn't worry about 1/2 ply as long as it's adequately fastened to the roof framing.  Same with the metal roofing itself - your fastening schedule and fasteners are key, especially at the edges.

   Anyway, good luck and I hope some of that helped.

   Andy

5. 
   Piffin | Feb 29, 2004 04:43am | #20

   You may have things different in Florida due to moisture. Can you cite a link to any manufacturer that recommends fasteners in the ribs instead of in the flats. Personally, I have never heard of this from a manufacturer. 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

6. 
   CombatRescue | Feb 29, 2004 05:53am | #22

   Piffin,

   Sure, there are two manufacturer's products available in my area.  One, JM Metals, doesn't have install info on their website (http://www.jmmetals.com), but I have their literature I can scan and post if you'd like.  The other is Southeastern Metals (http://www.semetals.com) The install instructions are at: http://www.semetals.com/MetalRoofing/5V-CRIMP_DETAIL_MANUAL.pdf (A PDF file, and mind the word wrap).

   Andy

7. 
   Piffin | Feb 29, 2004 06:29am | #23

   Thanks, That is a good resource. Metal sales puts out a similarone.

   That style roofing is one I haven't seen for twenty years and thought was out of production. it is left over from the era when lead heads were used to hold down the materials. No wonder they hold to the old patterns for placement of fasteners.

   It probably works OK for that style crimp along with all the extra fasteners they show holding in the pan bottoms on edges, but there are still just as many good arguments for screwing on the ribs, especially with the newer crimp styles that are made for it. I've seen failures both ways. The only sure way to avoid failure at screws is to avoid screws withy a standing seam roof.

   I do recommend the larger screws too for the displacement and holding. 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

8. 
   CombatRescue | Feb 29, 2004 10:00am | #24

   Yeah, this style roof is fairly common here in Florida - very common in Key West.  It's part of the "florida vernacular" style of architecture, so a lot of historic homes have it. Standing seam is common here too, though not as much for residential roofs (asphalt is #1, of course).

   Kind of interesting how different parts of the country use stuff you don't see in any other part.  Actually, most of the old homes near my house (including mine) originally had cypress shake roofs, but you can't get quality cypress anymore and they don't do well in hurricanes, so the 5v crimp has become the look for older homes. It is now trendy with newer houses as well.

9. 
   Piffin | Feb 29, 2004 04:38pm | #25

   local trends are funny. That V-crimp looks like the stuff I saw on shacks down by the tracks when I lived in Gainsville in the 70s.

   In Colorado a popular one is called Cor-Ten which is a very heavy gauge corrugated roofing that looks like old mining camp sheathing, It is without coating and intended to rust to a protectice patina. I hated working with it!

   Some of these trends seem to try to look old or poor or whatever. Sometimes it ends up looking nice and quaint like the surronding architechture and other times it looks just plain UGH! 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

10. 
    CombatRescue | Feb 29, 2004 09:15pm | #30

    Yeah, local trends are weird.  I'm originally from Denver and my Father was a GC there (My brother since took over the business).  Down here in Florida, there is virtually no wood framing, for the ground floor at least.  Some new 2-story tract homes have wood-framed second stories, but most walls here are block.  Also, no one builds roofs - everything is done with trusses, even high-end custom homes.  In fact the trend with high-end homes here now is poured-concrete walls or a combination of block and poured concrete.  What a change from my experience in Colorado!

    I really like the look of the 5v crimp on houses I've seen down here, even when it's on the newer ones.  But it can really look terrible if not installed correctly.  If the screws don't line up and the trim and flashing isn't cut to fit properly, it can really look bad.  Some make the mistake of using a saw to cut the metal, but the shavings get on the Galvalume surface and corrode it within a few weeks.

    It is energy-saving though, as it really helps reflect the viscous summer sun.

11. 
    sleddriver | Feb 29, 2004 07:57pm | #27

    Thanks for posting those Andy, great installation information. I was surprised to see that they have a manufacturing plant in San Antionio, Tx.

    5V crimp is very popular here . . . I saw one house where the entire roof was screwed through the narrow peaks . . . man that must have taken a long time.

12. 
    CombatRescue | Feb 29, 2004 09:04pm | #29

    Actually, it's easier to install the screws in the crimp.  You lay a bunch of sheets together upside down and pre-drill the holes from the backside.  The crimp keeps your bit from dancing all over the place.  Drilling many sheets at a time ensures your holes line up and look uniform

    Andy

13. 
    sleddriver | Mar 02, 2004 01:45am | #31

    Noticed your remark to Piffin about not cutting the panels with a saw. Are you talking about a metal blade in a circular saw? Since the environment you're in has constant sea breezes, corrosion must happen quite fast. What metal cutting tool do you recommend?

    I plan on predrilling the panels, much easier to get everything to line up. I noticed when one panel was drilled from the top, that the metal 'climbed' up the drill bit and left a burr. . . anyway to prevent this? I have some scrap and I'm curious if this will only happen to the top panel when 7 or 8 are stacked together.

    thanks in advance

14. 
    CombatRescue | Mar 02, 2004 05:40am | #33

    The best thing to cut the metal panels is probably a nibbler.  There are electric and air-powered versions.  Good ones are somewhat expensive, but I think you can rent them. They leave a nice clean edge and don't generate small metal filings that can ruin the galvanized finish of the steel.  If you do use a saw, you have to be meticulous about making the panels free of the filings once they're installed, because staining in the finish from filings voids the manufacturer's warranty.  Corrosion is a severe problem in my area, but those filings will rust pretty quickly and ruin the metal finish in most climates.

    I haven't had problems with burring, but most of my holes went into the ribs.  I'd recommend buying some good quality bits designed for metal and don't put a ton of pressure on the drill.  If you press too hard, in my experience, the burring gets worse.

    HTH,

    Andy

15. 
    ljtoday | Apr 05, 2004 05:12pm | #43

    To avoid the metal burring problem-use a "bullet point bit"....they are made by a variety of companies-black and decker included. They are indispensable bits for work with metal-they have a raised outer ridge that cuts the circumferance of the hole before the spiral shank plunges all the way in and extrudes metal up the shank (which is the problem you are experiencing). Run the bit at as close to 10,000 rpm as you can (ie: go full speed on whatever drill you use, and don't force the bit).

    Great thread everyone-good job!

16. 
    sleddriver | Feb 29, 2004 08:22pm | #28

    I share your concerns, I have a metal roofing project coming up, but why would a #9 screw in half inch ply hold less than a roofing nail in half inch ply. I'm no roofer but I know that a screw has several times the withdrawal resistance than a nail.

    You're right . . . on that point . . .nothing else but fastener (screw vs. nail) in 1/2" ply, a screw will always win (in a comparable diameter to the nail).. .  . hands down. The hitch comes when it attaches something that expands & contracts to the deck. Asphalt shingles are a very soft material . . . it's not going to push a metal fastener around. A large metal panel (say 3' x 15') will because the large panel acts like a lever . . in this case an expanding & contracting lever.

    My belief is that you need more fastener buried into more wood (i.e. a stronger anchor) when dealing with metal on an exposed fastener panel.

     

17. 
    billyg | Mar 19, 2004 09:12pm | #36

    The roofing nails are somewhat protected by overlapping shingles so it may not be a big deal if they loosen a bit.  On a metal roof most of the screws are exposed, so it IS a big deal if they loosen -- particularly if they are in a trough area of the roof that sees lots of water.  The nails should never get that kind of exposure.

    Big difference in application!  Think about it.  ;-)

    Billy

2. 
   sleddriver | Feb 28, 2004 06:23am | #12

   My old three tabs are only about 1/8" thick, max. They are flat. No curled edges, twists, cups, splits or warps. Is 26ga metal really going to deform if put down on top? Over the thicker (or wood) shingles, I can definitely see where they would cause a problem telegraphing through the metal.

   I agree that 1/2" ply isn't enough. One manufacturer in Houston I talked to a couple of days ago said they do all of their tests using 1/2" ply & #9 screws without any problems. My point was what about over time? 5 years? 10 years? I'm more concerned with screw-holding ability over time, temperture & weather than I am about high wind ripping the roof off. If the screw backs out, it could cause a leak. If I have to go above & beyond what they recommend, so be it. Frankly I wasn't very impressed with his answers. He actually put the phone down on his desk while he fetched a piece of metal panel (I have no idea which one), put it on the floor and walked around on it. . . . I almost laughed.

   Basic Question:  Is the whole purpose of furring the roof to separate a metal panel, that expands & contracts far more, from a wood deck, which doesn't? Or is it to give you a better surface to screw into? Or is it to reduce heat conduction from the metal to the roof decking? I missed that question about 2 miles back and now I'm wondering . . . what is the purpose in the first place?

   When you fur a roof, do you put down boards so that their edges are flush with the facia boards at the eves & rakes first, then 'fill' in the middle area? Or do you set it back from the edges a bit? I'm also assuming these are screwed/nailed to the roof rafters?

   High winds? . . . here? . . . .naw . . . . . . just a bit o' breeze.

   Fortunately my valleys are few (only three) and short (5' max). If I had a complicated roof, no way I'd ever do this myself.

   Thanks for the reply

1. 
   DavidxDoud | Feb 28, 2004 06:54am | #13

   re: metal over three-tabs - ya can do it, not as clean as over flat or skip sheathing,  but it isn't like it's a big deal - I would make an honest effort to place the screw just above the bottom edge of the shingles -

   and 1/2" will hold - - until the going gets tough - you feel lucky? you might never have a problem...- - one thing,  if you lose it in the wind,  you still have the shingles to keep the water out -

   as far as I'm concerned,  furring is something substancial to screw to - - this movement thing (temperature expansion and contraction) is going to happen no matter what you screw to,  but failure of the attachment around the perimeter where that movement shoves the screws back and forth is minimized with longer screws and substantial substrate -

   When you fur a roof, do you put down boards so that their edges are flush with the facia boards at the eves & rakes first, then 'fill' in the middle area? Or do you set it back from the edges a bit? I'm also assuming these are screwed/nailed to the roof rafters?

   I would plan my detail around the eves and rakes so the the new facia had solid attachment to the furring and to the existing facia - might have to have 2 or 3 elements in the system to achieve that,  depending on the existing circumstance - I like to run a champhered 1X2 around the perimeter at the top of the facia butting up to the metal - a finishing detail... I'd screw the furring thru the roof into the rafters - (4" galv deck screws thru 2X + 1/2" ply) or at least use 20d spiral galv decking nails - make it tight and solid - leave no place for the wind to work the system...

2. 
   Piffin | Feb 28, 2004 04:55pm | #17

   " Is 26ga metal really going to deform if put down on top? "

   yes, it will telegraph 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

4. 
   maverick | Feb 24, 2004 12:23am | #7

   to every homeowner who thinks he is capable of tackling a roofing project I give the same answer. Yes, maybe you can. but find another project that will give you the same amount of satisfaction knowing you completed it yourself and stay off the roof!

   if you dont fall off and break something, you'll screw up the flashings and end up paying someone, with the proper experience, double to finish it for you

1. 
   brownbagg | Feb 24, 2004 01:05am | #8

   let me offer, chaulk line, tennis shoes and metal roofs do not go together, trust me.

1. 
   sleddriver | Feb 28, 2004 05:38am | #10

   Did gravity & height have anything to do with making that a slippery combination?

   Any video?

5. 
   hasbeen | Feb 29, 2004 05:29am | #21

   1.  What Piffin said.

   2.  I'm being redundant, but:  Don't put metal directly onto mineral surface roofing.  Building vibration causes abrasion of the back surface of the metal and abrasion leads to rust which leads to failure.  I've pulled up some badly rusted metal (addition job) which looked fine on top, but was laid onto mineral surface.

   Yes, the shingle's irregularities will telegraph through if you put metal directly on the shingles.

   Google for Metal Sales.  They have what they call "fat boy" screws that are 14 guage with 5/16" head for the exposed fastener metal products.  They don't show them on their website, but at least in Denver they have them to match color.  Ordered them yesterday for my new roof.

   If you really want to go whole hog:  Strip the shingles down to the plywood.  Put down RoofTop Guard II.  It does a much better job of sealing around screw/nail holes than any felt paper.  Put 1x4 across the surface at 16" oc and use 1 1/2" fat boys to put down the metal.

   I've always just driven the screws through the metal without predrilling, but this time I'm going to predrill.  (Thanks for the suggestion, Piffin!)

   I live in a windy place (it's screaming right now!).  I built my garage six years ago and put Metal Sales' "Pro Panel II" directly onto 1x4s (on 16" centers) which are nailed directly to the rafters.  After a recent BT discussion on this topic I pulled out a ladder and looked over the roof carefully:  No loose screw.  Never a leak.  AND the 1x4s (I learned to refer to such as "skip sheathing") stick 12" out from the gable end on the east and west with only the screws to hold the edge down when the big gusts hit.  Again, no problems after six years.

   If you want, you can cut future maintenance by getting matching fascia metal and gable end (barge rafter) trim.

   Something is what it does.

1. 
   sleddriver | Feb 29, 2004 07:24pm | #26

   I'm being redundant, but:  Don't put metal directly onto mineral surface roofing.  Building vibration causes abrasion of the back surface of the metal and abrasion leads to rust which leads to failure.  I've pulled up some badly rusted metal (addition job) which looked fine on top, but was laid onto mineral surface.

   Thats the confusing part:  First, I hear "Yea, you can just put it down on your old asphalt shingles, no problem". Second I hear "Do it the way the manufacturer specifies". Third I call the manufacturer and they say "Yea, you can lay it directly down on your old asphalt shingles and it won't void the warranty." Fourth, I get to thinking 'Wait a minute. . .this galvalume/galvanized stuff is a coating, right? . . and the metal expands & contracts, right? . . .so I'm going to screw down this moving panel to an abrasive granular surface and the manufacturer says it's OK . . no problem . . . . . . that's nuts and it doesn't make sense . . . to me anyway'.

   What 'grit equivalent' are the granules on asphalt shingles? . . . 40?  . . . 20?  It doesn't make sense to slowly abrade the backside of a panel over time. . . . so much for the manufacturers 'advice' . . . . .

   BTW . . here in central Texas we average about 33" of rain a year. . . . and we're in the top 10 areas of the whole country for the combination of high heat & high humidity.

   Thanks for the screw link . . . I'll look it up.

   There are some very nice underlayments besides 30# felt.

   Highest wind I've ever seen at my house in 22 years is a 40mph gust coming in from the North (I have a weather station). Sustained winds may be 15mph, but it's rare . . . again at my house location.

   I'll definitely have the gable ends along the rakes trimmed out with metal . . wouldn't consider leaving it open.

6. 
   MikeCallahan | Mar 02, 2004 04:51am | #32

   One reason you do not want to locate the screws on the ribs is corrosion. For some reason the exposed part of the screw under the rib is exposed to moisture and will corrode to nothing if there is a lot of moisture. I have replaced screws in our dry climate that were almost completely rotten where the threads were exposed under the ribs over 30lb felt on plywood. The ribs should only be screwed where there is a lap and then only a stitching screw is used. I lay out the holes on a flat surface and drill several sheets at a time like Piffin described. Where the sheets lap, the sheet under should have an under size hole so the metal will suck together. So the holes line up I drill those undersize holes when I am on the roof.

   The short screws are cheaper too. ,There is a much better connection when the screw goes directly into the plywood without passing through air too. If you screw into the ribs then you risk deforming the metal too. The edges can creep and make your layout go out of square. Not to mention those ugly dimples from too much torque.

   I notice your handle is Sleddriver. Would that be a dog sled?

   Mike Callahan, Lake Tahoe, Ca.
1. 
   sleddriver | Mar 19, 2004 02:04am | #34

   I'm a bit confused as to why you discovered corroded screws in a 'dry climate'. There must have been water flowing between the underlayment & bottom of the roof panel.

   True the short screws are cheaper, but I'm more concerned with sinking them into enough wood and having them stay in place than save a few bucks.

   I drove several screws through ribs with an adjustable clutch and seated the washer without deforming the metal, or creating ugly dimples or striping the wood. Not sure what the fuss is about

   No dog sled . . . . .just a station wagon.

   thanks,

1. 
   DavidxDoud | Mar 19, 2004 02:58am | #35

   if you're going to work with sheet metal,  this is a very handy tool - - quite quick and clean - it does not work well at crawling across high ribs at an angle, but with a little practice will get you close,  and you can clean up with sheet metal shears (wyss,  or some such - need R, L, and straight set,  good ones)"there's enough for everyone"

1. 
   sleddriver | Mar 21, 2004 11:33pm | #37

   Didn't realize B&D made such a thing.

   I recently did pick up some straight sheet metal sheers made by Midwest. I'm always impressed at how a good tool makes the job easier with better results.

   I've been taking some photos of my project and have some more questions for the group, I'll have to learn how to attach them to a msg.

   thanks,

1. 
   sleddriver | Mar 22, 2004 07:25pm | #38

   Well the rainy weather has delayed me quite a bit getting started on my roof project. So I've been tracking down some other things and have posted some photos below.

   First, I have some fascia rot at a corner miter and after reading the article in FHB about using expoxy, I want to give it a try. I already ripped out one corner that was worse and put in all new wood, but this corner 'hovers' above a lower roof section by about 6" . . so I can't get under it. Any ideas? Epoxy suggestions?  I used the West system before, but not to fix rot.

   Second, I noticed the flashing used on a gable wall has an edge turned back, like a hook, which results in a bump or ridge where it lifts the shingles up. See photo. It doesn't look right and I'm going to have to remove it to get some 1 x 4's to lay flat up to the edge. Do I have to rip up the shingles next to the wall and pull all the nails out of the siding to get it out of there? Any tips, tricks or techniques suggestions? I'd also like to cut the siding back so that it isn't too close to the new roof. I'll have to anyway because the 1x's will lift the metal roof above the bottom of the siding.

   Third, there is another photo under a close eve where I encounter more of the 'hooked' flashing . . again I have to remove it if I want the 1x's to lay flat . . any suggestions?

   thanks

2. 
   Dinosaur | Mar 26, 2004 06:14am | #40

   To answer the majority of your questions:

   1. Ribbed metal roof + DIY + Hips & valleys = frustration, shredded hands, and a bad job. Don't do it. Use 3-tabs. The manufacturers' instructions make it look easy--it's not. Cutting that stuff without factory jigs and slicers is never satisfactory, and the way it is designed to go together makes Lego look elegant.

   If you insist--it's your roof and your hands, after all--

   1. Get an air nibbler and a metal roofing blade for your circ saw. Plus a good set of aviation snips. Plus a Sharpie marker--chalk blows right off the paint as soon as you approach the tool to the line you want to cut.

   3. Half-inch ply for a 5 in 12 roof is marginal, no matter what the roof covering. I would definitely strip the 3-tabs before you lay anything else on top. Not even a question in my mind. If you want to 'do it right' you might even consider laying another thickness of ply--especially if the rafters or trusses are at 2' centers--say 3/8 ply glued and air-nailed with roofers. Make sure the joints in the 4x8s don't line up anywhere. Use minimum 28-ga galvanized flashing in all valleys, 24" wide at least.

   4. Use a good underlayment on the roof deck. Minimum 15-lb felt; 50# roll roofing is better, if you can find it.  90# is overkill. Lay it horizontally and lap the edges 18" for full double coverage. Strap over it with 1x3s at 90-degrees to the trusses/rafters. Nail these on with two 2½ inchers into the rafters at each crossing. Air nails hold better because of the glue on them. Lay your strapping at 24" centers up the roof. Box the whole roof in with furring, of course, and make sure you have a solid sub-fascia whereever necessary.

   5. Do not drill the screw holes in the roofing, punch them. If you can't get the screw gun to start its own hole by smacking the screw gun hard with the heel of your hand, buy a sharp metal punch and use it to make a small starter hole. Then drill the screw in with the screw gun. A gyprock gun with the nosepiece removed works well. Screw through the ribs. Don't over tighten or you will flatten the ribs. They will spread and deform the sheet of roofing and it'll go off square. You need to squash the rubber washer--not the ribs. Lay the edges of each sheet of roofing to a chalk line vertically snapped on the roof and 3-4-5'ed to a chalkline parallel to the eaves.

   6. The screws need to penetrate the furring. That is sufficient. Overlong screws to sock into the roof deck itself will just kick sideways out of the bit in your screw gun while you're starting them and cause you to curse a lot. Plus they'll cause bridging.

   7. Use butyl rubber caulking to seal each vertical lap joint between adjoining sheets. Use thermoplastic caulking in a matching colour for all visible spots such as around roof penetrations and to seal the cover strips in the valleys. Get an air-powered caulking gun.

   8. But like I said at the top--You'll be better off using 3-tab asphalt shingles. To get an idea of why, take a look at the thread 'THE ROOFING JOB FROM HELL'. http://forums.taunton.com/tp-breaktime/messages?msg=34292.1

   Good luck.

   Dinosaur

   'Y-a-tu de la justice dans ce maudit monde?

   Edited 3/25/2004 11:28 pm ET by Dinosaur

3. 
   sleddriver | Mar 26, 2004 09:28pm | #41

   To answer the majority of your questions:

   1. Ribbed metal roof + DIY + Hips & valleys = frustration, shredded hands, and a bad job. Don't do it. Use 3-tabs. The manufacturers' instructions make it look easy--it's not. Cutting that stuff without factory jigs and slicers is never satisfactory, and the way it is designed to go together makes Lego look elegant.

   Yea, I would agree. If I had a hip roof period, I wouldn't do this. Two 5' valleys are formed where the covered walkway attaches perpendicularly to the house. Another 5' valley & opposing ridge is formed when the walkway takes a 90 degree turn and attaches to the side of the garage, underneath the garage roof. Both house & garage roofs are gables, so I'm dealing with large sheets and cuts will be made parallel to the ridges on the roof panel. BTW, the ridges on this panel are only 1/2" high, not the 2 or 3" you had to deal with.

   If you insist--it's your roof and your hands, after all--

   1. Get an air nibbler and a metal roofing blade for your circ saw. Plus a good set of aviation snips. Plus a Sharpie marker--chalk blows right off the paint as soon as you approach the tool to the line you want to cut.

   Bought some aviation snips and they work great. Sharpie is a good idea. Heard somewhere that chalk is slipperly & can stain metal. I'll have the supplier cut the panels to length on their large sheer before delivery.

   3. Half-inch ply for a 5 in 12 roof is marginal, no matter what the roof covering. I would definitely strip the 3-tabs before you lay anything else on top. Not even a question in my mind. If you want to 'do it right' you might even consider laying another thickness of ply--especially if the rafters or trusses are at 2' centers--say 3/8 ply glued and air-nailed with roofers. Make sure the joints in the 4x8s don't line up anywhere. Use minimum 28-ga galvanized flashing in all valleys, 24" wide at least.

   4. Use a good underlayment on the roof deck. Minimum 15-lb felt; 50# roll roofing is better, if you can find it.  90# is overkill. Lay it horizontally and lap the edges 18" for full double coverage. Strap over it with 1x3s at 90-degrees to the trusses/rafters. Nail these on with two 2½ inchers into the rafters at each crossing. Air nails hold better because of the glue on them. Lay your strapping at 24" centers up the roof. Box the whole roof in with furring, of course, and make sure you have a solid sub-fascia whereever necessary.

   Laying the panels directly down on the old shingles is a bad idea, even though the manufacturer says it won't void the warranty. Furthermore, I don't believe 1/2"ply  is sufficient enough to hold screws, so I'm going to use either 1x's or 2x's nailed into the rafters on 16" centers.

   5. Do not drill the screw holes in the roofing, punch them. If you can't get the screw gun to start its own hole by smacking the screw gun hard with the heel of your hand, buy a sharp metal punch and use it to make a small starter hole. Then drill the screw in with the screw gun. A gyprock gun with the nosepiece removed works well. Screw through the ribs. Don't over tighten or you will flatten the ribs. They will spread and deform the sheet of roofing and it'll go off square. You need to squash the rubber washer--not the ribs. Lay the edges of each sheet of roofing to a chalk line vertically snapped on the roof and 3-4-5'ed to a chalkline parallel to the eaves.

   I'm going to stack several panels together and drill the holes on the ground. I plan on using a larger screw, so I can use a larger drill bit which won't break as easily. I plan on having some extras on hand. Never heard of punching them one panel at a time . . seems like it would take forever. I like the 3-4-5 idea, I can get a 12-16-20 on my 14'4" x 25'-1" garage. I'll use the eve as a baseline and trim the rake edge if necessary. The rake trim will hide it. I don't know how far off my roof is yet. . . but I'm not assuming it's square. Will definitely snap vertical lines as I go to make sure I stay on track.

   6. The screws need to penetrate the furring. That is sufficient. Overlong screws to sock into the roof deck itself will just kick sideways out of the bit in your screw gun while you're starting them and cause you to curse a lot. Plus they'll cause bridging.

   Good point. . . when using screws to attach one piece of wood to another, I always make sure that the threads only engage the lower piece. Otherwise it'll jack and leave a gap. In this case it'll just make another hole through the decking which is unnecessary & could cause the roof to lift.

   7. Use butyl rubber caulking to seal each vertical lap joint between adjoining sheets. Use thermoplastic caulking in a matching colour for all visible spots such as around roof penetrations and to seal the cover strips in the valleys. Get an air-powered caulking gun.

   I planned on using Sonneborn NP-1 in a color to match the metal. I like the air-powered caulk gun.

   8. But like I said at the top--You'll be better off using 3-tab asphalt shingles. To get an idea of why, take a look at the thread 'THE ROOFING JOB FROM HELL'. http://forums.taunton.com/tp-breaktime/messages?msg=34292.1

   That was quite a job . . . were parachutes included in your safety equipment? 25 in 12? Didn't know the numbers went so high! That's 64 degrees pitch! We don't have houses like that down here . . no snow loads to worry about either. Just lots of humidity, searing heat and 33" on average of rainfall. Our weather is best described as "Extended periods of drought interrupted by severe thunderstorms & flash floods."

   Merci

4. 
   Dinosaur | Mar 26, 2004 10:27pm | #42

   Yea, I would agree. If I had a hip roof period, I wouldn't do this. Two 5' valleys are formed where the covered walkway attaches perpendicularly to the house. Another 5' valley & opposing ridge is formed when the walkway takes a 90 degree turn and attaches to the side of the garage, underneath the garage roof. Both house & garage roofs are gables, so I'm dealing with large sheets and cuts will be made parallel to the ridges on the roof panel.

   I am having trouble visualizing this layout. Can you post a photo or a plan view?

   In general any hip or valley requires an angled cut, by definition. Once you get to that point, you will have to deal with the fact you can't make a decent on-site joint between two panels of ridged metal unless you're towing a 25' Wells Cargo containing a hydraulic shear and the factory jigs for the panels you want to cut.

   Your supplier is expected to pre-cut the panels to length--in fact, he ought to come out to your house and measure the roof himself to avoid any problems. But he will not, unless you make special arrangements with him, make the angle cuts for the valleys or hips. Many times the local dealer does not have the tools either, and 'cuts to length' for you by ordering it that way from the MFGR. I don't believe it would be practical for the hip/valley angles to be pre-cut, even at the factory, because that would entail having laid out the roof precisely to determine exactly where each sheet goes to within a quarter inch.

   To compensate for this fact, pre-fab metal roof manufacturers supply various cover trims, some with cut-outs to sit over the ridges, some not--and you then have to stick in foam rubber inserts to block the openings created by the trim strip sitting up on top of the ridges. This is not quality nor elegance in my book. It is simply quick and expedient. You want a good metal roof, you get ahold of a guy like Greencu (here on the forum) and pay him what he asks. Then you sit back and admire it for the next 75-100 years.... 

   I'm going to stack several panels together and drill the holes on the ground. I plan on using a larger screw, so I can use a larger drill bit which won't break as easily. I plan on having some extras on hand. Never heard of punching them one panel at a time . . seems like it would take forever.

   Ideally, you punch the screw in directly in place. The way this is done is to put the screw into your gun, set the point on the steel where you want it, then use the heel of your off hand to smack the heel of the gun hard enough to make a small pinhole. That is enough for the threads to get a bite; after that, the screw just pulls its way in. This is the fastest way, but your hand will be sore at the end of the day--or even by break-time, LOL....

   I planned on using Sonneborn NP-1 in a color to match the metal. I like the air-powered caulk gun.

   I'm not familiar with Sonneborn. I use Mulco products here. http://www.mulco.ca Click on "industrial" on the English home page; you get a better selection of product shown.

    You need to use different types of caulk for the two different applications. Use the butyl rubber to seal all the lap joints where you join one panel to the next. For one thing, it's cheaper than silicone or thermoplastic--and you'll be using a lot of it. For another, it's easier to handle in this application and squishes down perfectly between the two sheets of metal so you don't get any lift. Most importantly here--maybe not so down your way--is that it stays flexible at -30 Celsius.

   Dinosaur

   'Y-a-tu de la justice dans ce maudit monde?

   Edited 3/26/2004 3:33 pm ET by Dinosaur

   Edited 3/26/2004 3:43 pm ET by Dinosaur

2. 
   JohnSprung | Mar 26, 2004 04:03am | #39

   This looks like a powered version of the cutter accessory for the Tapco brake.

   -- J.S.