It’s crazy that 90% of the people in comments say rib. I started as a residential and commercial roofer for my Dad when I was 15. Now it’s my company. I do at least 100-120 roofs a year and you need to go on the FLAT. Modern screws are meant for the flat. They won’t tighten and grip and be leak proof on the rib. They’ll work themselves loose and won’t even seal properly on day 1, let alone day 2,000… Screw on the flat folks. That’s what every professional I know does.

Thanks for this video. When you mentioned snow rake I was sold.

Installing steel roof over my deck this weekend, I will be going on the flat. Thanks for the knowledge Ken !!!

haha ribs in my opinion, holds the seems tighter. Plus if they work loose water is always going to flow off the ribs to the flats...

You are absolutely right about the roof rake catching the screws if they are on the rib…..disaster!!

I can tell you some screws or nails will back out over time. The longer the panel is, the more the movement (problem ). So when there is a loose screw on the peak it still sends the water down to the flat. When the loose screw is in the flat, water runs into the structure! Expansion and contraction will cause a screw hole to elongate over time no matter how tight the screw is. The roof is pretty with the screws in the flat, and it's quick to install. . But the roof with screws in the peak will not leak for 50 years, even tho many screws will be loose. THERE IS A RIGHT WAY TO SCREW DOWN A ROOF.

When I started in the late '70's in Key West, FL many of the roofs were, and still are, 5-V or what we called V-crimp and we all put the nails, no screws, on the ribs. Also, the washers were made of lead.

I put a steel roof on my house 4 years ago I put the screws in the flat and haven’t had a bit of trouble.

I like it on the flat for walking on the roof, the screw gives your shoe something to bite on, keep you from slipping as easily

Screws in the rib will move back and forth and eventually work lose or come out. In the flat the screw doesn’t move and the panel will enlarge the screw hole but the screw still covers and won’t leak.

In tropical weather countries, it is preferable to install on RIB as the water will eventually flow from flat, and in snowfall region its prefer to install on FLAT, so that we can easily remove the snow.

I was taught to put it on the Rib, so water Runs down sides of Rib, if on the Flat it can have Tons water washing down the flat surface towards it and more chance to leak. Also screws on the flat can be blocked by a stick and cause leaves to build up, but if it stops on a ridge its higher and leaves will Slide under it. (no snow here in Florida)

Very informative VDO thanks :)

25 years in carpentry jut put in on the flat. especially in Canada. The head sits tight to the roof

I was always taught on the rib. Water runs downhill and in the lowest part of the tin..every screw potentially becomes a leak. On the rib is the highest point..water runs off down to the flat part of tin and downhill. Less chance of leakage on the rib.

Screwing on the rib adds back tension to the rubber screw seal. However, if attaching to furring strips, most screw on the flat for strength of attachment. My rule of thumb is, if you’re installing on solid decking, typically new construction or a complete roof rebuild, screw on the ridge. If you’re installing metal roofing on furring strips over an old roof, screw on the flat to get deeper penetration & additional rigidity of install on the roof. I could be wrong.

I prefer to screw into the rib to reduce the chance of leakage years down the road. One caveat is you must not over tighten the screw. If you compress the rib you effectively widen the panel and cause alignment problems with subsequent sheets.

I have been doing it for a long time and have done it both ways and never had a leak either way. The problem with the flat is when you try to screw the laps on the flat sometimes the sheet appears to not lay down good. The laps seem to fit better when you go through the rib so i have actually done it both ways on the same job before. In the field I screwed on the flat and at the lap, on the ribs. I know, I just created a black hole. Again, never had a leak on any of my jobs. Even if i did I would not know it because I use synthetic felt under it which sheds the water all the way to the gutter. :)

Putting it on the Rib is what I do, but I do not let crackhead day laborers help me screw it off because they will over tighten them and bend the metal. Me and my brother have never had a call back on leaks.

I think this stems back from the early days of tin as it was continuously corrugated and the rib was the obvious choice as the lower portion of the rib wouldn't allow the nail (no screws in the old days lol) hole w the lead swatch to seal properly. I believe with today's technology both places are acceptable as long as the surface is flat

great vid. ive found the older guys are adament on the rib but i worked for a company that needed to do it faster so we just went on the flat. theres definetely no wrong way just pros and cons to both methods

I worked for a medal building contractor we used R Panel you receive a written warranty from them they will replace the panel if there is a problem but you must place the screws at their requirement , in the flat, and lap screws at the joints of each sheet

I prefer the rib but I can get the screws straight and not over tighten them but the big key is when you're done it's a really good idea to gently walk over the ribs and listen for a pop ! If you hear a pop stop and tighten a little better but not everyone can do it

I’ve seen way too many leaks later down the road that were flat!

If you look again at your example of "both" it actually only recommends a rib screw where the endwall flashing meets the panels. Otherwise it should be in the flats. I have looked at 10 different manufacturers detail guides and none recommend a rib installation.

I was sure hoping it was gonna be on the flat. Seems to make more sense.

This may sound weird, but I'm desperate to find a recording of the sound an electric drill makes when driving a self tapping screw into sheet metal like this. I can recall the sound from this one time I was assembling a shed with my dad where every time we drove a screw through some sheet metal it would reverberate with a loud racket as the ratchet mechanism in the drill engaged. Does anyone know where I can find a clip of a video with this sound? I couldn't tell if your demonstration was making the sound because it was sped up.

Some people choose to screw the rib, because the flat will hold debate and water, whereas the rib is high above the running water, they both are subject for having them move during winter months and summer months,

Interesting debate here, I’m a handy man & was taught 25 yrs ago doing a roof with grandparents to put it on the rib. Since then I’ve seen both & always scratched my head wondering who was right. I still continue to screw into the rib & haven’t had any problems, touch wood !!

Modern screws with cupped washers need to be under enough tension to set the washer which cant be done properly on the rib (the exception being heavy gauge) without deformation. Back when, not so long ago, you would nail on the rib because you know damn well they're going to leak and so you want to minimize contact with water.

My boss's shop screwed in the rib and roof leaks when it rains or snows melts. Like you said panels move do heat, so when it is screwed in the rib the same movement would have more leaverage loosening screw, and rubber gasket would have more area to seal on the flat. In pole barn application I would think screws would grab better on flat part, providing a little resistance to wind rocking the building

Always put it in the flat, always. Rib screwing is done by the old guard that can't let go of their ways...and that is it. I'll put it this way, the ONLY time I've had to get on a roof and replace screws or panels was when it was screwed in the rib. And I've never had a roof that I've personally done leak so far with them in the valley. That being said a metal roof should never be installed during cold months, unless you plan on getting on the roof in the warmer months and putting a quarter turn on every screw...the washer won't heat up and seal correctly in cold weather and the metal will expand when the summer comes. All sorts of problems happen. I flat out refuse to do a metal roof in dead winter.

I know of 2 flat screwed roofs that need to have all their screws replaced because the washers have dried out and small leaks have begun. One of these roofs had the premium cap that covers and supposedly protects the rubber from drying out. These roofs are about 15 years old. What is a bigger problem than replacing the screws is that the small leaks caused rotting in the runners and the same hole can't be used for fastening or worse yet the panel need to be removed and the runner board replaced with fresh if the leak was particularly bad. As a preventative measure, I'd replace screws every 10 years if screwed in the flats. If I'm doing exposed fastener from here on out I'm screwing into the ridges where the water doesn't flow. I think some manufactures recommend screwing into the flats because its more forgiving to a careless screwer and near useless warranty doesn't cover dried out washers.

With current technologies I say place screw in the flats...it'll remain 'tight longer' and 'tight' prevents leaks. However see my comment below.

I think when brand new, on the rib encounter less water. But...with age as the roofing expands and contracts, I can see the rib potentially getting more movement. Also...installing on the rib, if the installer does not have the clutch correct on the drill, he/she may compress and make a divot on the rib, impacting the seal. I am doing a small metal roof and I will install on the flat.

Ken- Love your channel! Wife and I are planning to build a home soon. (Wanna come down and build it? 😜). I am seriously considering exposed fastener metal roofing. (Budget saver). Do you see these often done for homes or just garages/ barns? Thanks!

How long do the rubber gaskets last on the screws? In AZ, the sun eats everything. I cant imagine that rubber lasting more than 7 years.

Screws in the flat make a much stronger diaphram. I'm constantly fixing leaks where screws are on the rib. If you do screw on the rib, it better be straight or it will leak.

Back in the day the fasteners were lead headed nail so you would put then on top of the rib. Now they have shielded neoprene heads on screws so they work best on the flats.

My roofer is putting it down on the flat, but a lot of guys here, put it on the rib, or beside the rib, because of snow and ice. When spring thaw comes, it melts off the rib and goes down hill to the flat and runs off the roof. So screws in the flat, are going to be in contact with more ice, and snow melt, as it melts off the ribs and goes to the flat. All the water runs down the flat. So every rain or thaw, any water is going down the flat hitting every screw. That said, I am having mine put right over top of the old shingles and it's going down on the flat.

If you screw it on the flat the expansion and contraction movement is less and it will slot the roof out just a little bit, my roof was done on top of the rib and it leaks it doesn't matter that that rib is higher up water is going to go if the screw gets worked loose

What would you recommend if you are replacing lead headed nails with screws on an old style corrugated tin roof? There really aren't any flats, its all wavy. Are you better off screwing new holes in the low parts and caulking the old holes? I've just been putting the screws in the old holes, most of the time I can still get a good bite(I tried prying out a few of the screws to test for holding strength, as long as the impact driver clicks once, I don't think they're going anywhere). If it isn't a solid hold I angle it to get a better bite with the head going uphill to shed water and will caulk the underside if any of the hole is showing. If I can't get a solid bite at all, I go to the next ridge and caulk the old nail hole. Alot of the roofs on my farm need the nails replaced, at the rate I'm going I'll go through 100 lbs. of screws easy. :)

I apply the tape caulking on the rib the screws on the flat! I’ve had no problems for decades! So, I stay with the flat!

Screwing on the rib you are essentially relying on gravity to keep water out.... Nothing wrong with that, as long as it works. Where I'm at we tend to get storms that will blow rain sideways. It's a great shingle remover too!

Haven't been able to wrap my head around fastening a flat washer to a cornered angle (the rib of 5v metal roofing) and expecting it to stay sealed.. Also, with the metal expanding and contracting, the rib seemed counterintuitive... I'm glad I've done more research and will be screwing on the flat, myself. Am I right in thinking that one wouldnt need to worry about leaks if the metal isn't screwed directly into the roof deck? For example, I'm leaving an air gap between my roof and underlayment, so I'm screwing the metal down onto 2x4s that sit above my roof deck. They are cross basseted over 1x3 furring strips which sit on top of the underlayment thats on the roof deck.. The furring strips are fastened to the decking and underlying trusses/frame. The 2x4s are fastened to the trusses and decking... so even if my metal leaks, it shouldn't be able follow the screw into my home.

Follow what the manufacture of the panels say and if you look almost every manufacture will tell you to screw it down on the flat. Remember all the testing is done on how the manufacture tested the panels with the screws in them. If they tested using the screws in the flats and you put the screws on the ridges none of their test results will be valid. You may also open yourself up to warranty denials if you did not screw the panels down in the locations as shown by the manufacture.

I don’t think it matters that much as long as you use a quality screw. I know I wouldn’t be using 29 gauge metal though. I only use 24 gauge on roofs. I only use 29 on little portable sheds.

I done it both ways, I can say for a fact that on the flat is the best and the easiest. When on the rib you have to be very careful not to over tighten, when over tighten the panels deform and go crooked very quickly, 2nd heat and cold put extra stress on screws, working them loose or breaking them..... When on the flat you can drive 1" screws in till drill rachets or screw stops with no worries of crushing panel ribs. 2nd, 1" screws are easier to screw in vs longer screws, longer screws seem to flip over and fall out of nut driver causing nut driver to scratch panel, then the screws falls off the roof and on the ground, very aggravating. Also when screws are on the flat it will make it easier to remove snow, if one has snow that is able collect on a metal roof. I also believe the ribs helps with expansions and contraction if screws on on the flat....... But when you have uneven roof with purlin strapping down, I find it better to put 2" screws on the ribs, on flat the screws have to be tight so rubber washer seals. So when on flat and tight and with strapping uneven, it will make panels bend and deform, but on the ribs the panel are not always tight to the strapping, therefore will not bend or deform the panels as much but the rubber washer is tight, also water is very unlikely to run up the rib vs down the panel, so when screws are on ribs, tightness is not so critical...... This is my unprofessional opinion on do-it-yourself metal roofing.........

I’ll probably do both just to it that way.

Im removing a roof on my farmhouse before i tear it down.. It is all screwed down on the ribs.. over the years they have all leaked like a sieve.. Removing the old screws was a pain.. almost every screw has been siliconed or caulked a few times over its lifespan of 20-25 years... Im about to roof my garage this week at home.. Seems to me like the flat will have a much better and cleaner seal without flexing the panels..

In other words, Flat = Stronger but risk of having leaks years later. Rib = Weaker but safer when it comes to leaks

for me, its important to put your holes where they leak the least when the screw isnt there anymore. rib

In the old days with lead head or neoprene collars they always used to say do it on the rib. But with modern screws I think its better on the flat. With drills there is a tendency to overtighten and flatten out the rib especially with impact drivers. Manufacturers are telling people not to use them but its become a bad habit. They recommend drills with adjustable clutches so as not to crush the collar and cause it to bulge and get exposed to sunlight. They dont care if you drill into the ridge but just dont deform it. You couldnt do that so easily with a hammer.

Go stand under any old barn that the roof was sheeted with used tin that had been nailed in the ridge and look at all the holes that you see daylight through, then go stand under the same barn during a rain, you will be hard pressed to get a drop of water on you, water can't stand on the ridge.

Most manufacturers put it on flat with screws and the old stuff was on rib with nails when putting on flat the rib is screwed at the overlap

Any real scientific material on this one can refer to? From disinterested sources not companies or manufacturers who have a vested interest in how soon the customer returns for supplies. In my corner,corrugated sheets attached to 2x4" 'laths' still cap the majority of roofs. For decades galvanized steel nails*were used and hammered into the ribs. It was (and still is) unheard of to fasten via the flats as the roofs leak like sieves if that is done. Given the arrival of impact drivers and screws with their fancy 2 cent washers, my concern is more about what diameter and length of screw should be used in a specific application. The umbrella*galvanized nails available were all 2.5 inches. Of course whether using nail or screw, going via the rib leaves a significant portion of the fastener not embedded in anything. Is holding power being compromised for possible leak prevention?

It is a tricky one. I am doing a chicken coop with a metal roof and was curious. It seems on the flat it could have more potential to leak because that is where water will be. It seems the rib could lose its rubber gasket seal easier. I am over it. I am going flat

I was taught the rib

how about put most screws on rib and just put few on the flat, the combination sounds good?

If you tighten the screws too tight won’t it flatten the rib?

Always put the screw on the flat part so that it holds the metal down tightly. The rib is for channeling the water away from the roof

Thanks for the honest info. I see benefits of both, but I will probably screw into the ribs. My reasoning is there is a chance I may remove and reuse at some point, and used metal with holes in the ribs I'd MUCH better!

On the rib where I live. Ice will grab when in the flat

Yeah we always did on the flat except at the ridge cap for obvious reasons. Been 25 years and there hasn't been complaints. There are far more important concepts to observe when roofing than this debate for preventing leaks.

i was taught nail the seam screw the pan or field

The egg or the chicken type question… I did my roof on the ribs but is suspect flat would be just as good (if done properly). BUT if screws are loose or damaged, I suspect leaks might have an easier time on the flat. Which brings me to say that it sure looks like you’re using the wrong tool to put the screws in. Is that an impact or a drill? I am not a pro roofer but doing a proper screw job needs a screw gun such as a CDF622B Dewalt with a clutch attachment. It’s way too easy to over or under tighten screws with those weak rubber gaskets IMO. Just my 2 cents.

There’s rarely water in top of a mountain!

Water runs off better from a higher ridge does it not, no pooling.

how are you not bending the panel while walking on it?

Doesn't the manufacturer have a recommendation? They must have installation instructions?

In a nutshell, ‘Republican or Democratic’....??? Thanks for the video 👍

my contractor screwed the flats 2 yrs ago, now I have some leaks, how is best way to reseal it?

Screwing the rib offers better water shedding, especially with 5V, but the tech specs I’ve always seen show screwing the flat with placement on both sides of the rib at the ends and on overlaps. But that is for central Florida.

Rib IST perfect probably you put screws flat leaks

For my vest is on the rib

I put mine on the rib. No leak 20 years

You don't put metal roof on a house.

Ribs 100% rain don't run down the rib the flats you depend on a washer not to leak doesn't matter if it's in the rib

Flat

Ok so if you screw it on the flat it voids warranty.. all roofing must be screwed on the rib. You screw only on the flats on walls. This is an argument between contractors but warranty only covers ribs. So if you want a warranty on your roof you might consider doing it correctly.

Flat