Replies

1. 
   Guest_ | Mar 03, 1999 09:33am | #1

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   Stan

   What kind of steel. . . raised rib, standing seam. . . what kind of roof framing?

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   Guest_ | Mar 03, 1999 09:37am | #2

   *Stan,Patrick or anyone of us can help you but you can help yourself by picking up the manufactures installation literature ahead of time at your supply house...Read it and then ask questions...Then we really can have fun with you!Jack : )

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   Guest_ | Mar 03, 1999 12:04pm | #3

   *A: Do get the manufacturer's instructions. Some of the manufacturers I'm familiar with discourage installation on roofs with as shallow pitch as your's.B: Follow the manufacturer's instructions and you should get a long lived roof with little maintenance.C: Installing metal roofs is a slippery business. Really pay attention to safety and keeping tethered; unless you like falls for their slapstick clown effect that is.

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   Guest_ | Mar 03, 1999 05:01pm | #4

   *I'm using "Mini-Batten" from Metal Sales, Inc. It is a concealed fastener and clip system. Both edges of the panel are fastened with the clip as opposed to snapping into the adjacent one. Metal Sales (www.msi.com) says these are good for 3:12 or better.-RobP.S. - What is this garage used for?-Rob

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   Guest_ | Mar 04, 1999 03:15am | #5

   *I've done a half dozen raised rib type, with screws next to the rib, and two tricks make it go much faster: (Read instructions first of course)1. If you space your purlins uniformly you can predrill all the sheets at once, when they are in a stack. This saves ALOT of time on the roof. I use a 1/8" drill bit for the standard hexhead w/rubber washer screws. Buy several bits as they break easily when drilling stacked sheets. Compress the stack with your hand near the hole you are drilling for less drill breaks.2. Take a 3-4' 1/4" nylon rope and tie small vise grips to either end by using a clove hitch at the vise grip's screw. Tie a long rope to the middle of the short rope. Have one person on the roof and one on the ground. The one on the ground clamps a grip on either side of the top of the sheet, handles up. The top person can uphaul on the rope, and when s/he reaches the bridle (short rope) s/he can grab that and climb the purlins like a ladder. I've done 30' sheets on a 12/12 roof using this method and it is really fast, easy, and safe. When the top person gets to the ridge, s/he can drive a nail or screw in the ridge, loop the bridle over it, the bottom person can then come up the ladder and adjust the bottom, with the sheet anchored.

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   Guest_ | Mar 04, 1999 04:02am | #6

   *Richard,I can attest to the effectiveness of both of your methods: Good advice!I recently had a raised rib roof put on a 7:12 pitch roof, but the screws were put in through the rib. There are two schools of thought on this and it seems folks are leaning to screws on the flat. Anyway, some of the screws leak a small amount (only several drops) when it rains. They don't always leak and it doesn't have to rain hard. Any advice for correcting the leaks. I thought about injecting polyurethane (PUR) foam into the rib cavity over the purlins from underneath to seal the screw. PUR is waterproof, but doesn't seem to stick to the metal very well. Thoughts?Regards, Steve Wright

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   Prairie-man | Mar 04, 1999 06:05am | #7

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   Rob,

   I just went to http://www.msi.com and came up with molecular solutions inc. Yikes ! I'm sourcing metal roofing right now for a new home project. Any alternative URL's for this company ?

3. 
   Guest_ | Mar 04, 1999 08:09am | #8

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   Re: leak prevention

   The last roof I put on was a BHP with a shallow pitch. We used two sizes gasketed screws for installation. One for fastening panels to sheathing(on the flat) and a shorter one for stitching the panels together(at the lapped ridges). This is called out in their instructions. No leaks because we followed their instructions of 2000rpm drill speed and depth sensing nose piece. But, a variable speed with a sensitive finger does just as good. Neither I nor anyone I know predrills for screws. They are all self tapping woodthread screws that self seal if not over or under tightened.

   BHP, and all others I've installed, recommend either roofing felt or neoprene mastic tape(for skip sheathing), and to caulk, lap and rivet sequential ridge flashings.

   One common problem is having the roofing out of square to the roof structure. So, if you can just tack it all up first then do the final screws.

   The big thing is to get the instructions for your brand roof and follow them.

   Hope this helps.

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   Guest_ | Mar 04, 1999 08:20am | #9

   *SteveThe reason your screws leak is because the screws weren't snugged down tight, compressing the rubber washer . . . it's what it's designed for!The only time I screw in through the pan is on side wall steel. I've heard the argument that the screws are brittle (self tapping-high carbon)and suseptible to torquing and snapping where the shaft is unsuported through the rib area. . . well. . . I've never seen any examples of this, and I've done more than a few raised rib metal roofs.Silicone caulk sticks well to metal roofing. If you can get to the screw from on top it's a better fix.

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   Guest_ | Mar 04, 1999 08:49pm | #10

   *Fred,I have never done a shallow roof as it is snow country here, so I think our applications are different.The predrilling will save alot of time and will not cause leaks, the holes are much smaller in diameter than the self-tapping screws, and save time first because you don't even have to think where the screw needs to go, and second because it makes the screw start more easily and cleanly.I b strongly recommend b nottacking up all the sheets first then screwing them down. This is much less safe, less time efficient, and is unecessary. If the roof is not square, the primary concern is to keep the bottom edge of the roofing running parallel to the eve. If the rake(first outboard)rafter is not perpendicular to the eve simply measure the length of the roof from the eve (point a) to the ridge at the rake rafter, then make the same mesurement from (a) along the eve driving a nail at point (b), calculate the hypotenuse of this right triangle (ab)*1.414, then measure the hypotenuse from (b) to the ridge marking (c) and put the first sheet up parallel to the line (ac). This is very accurate as the triangle is so large. Any mismatch at the rake rafter can be covered with metal trim that is available.The standard sheets here are 3' wide. If you screw them down completely as you lay them, you can reach just enough to drive a screw with out ever having to step on a metal sheet, except for the last one. Also, if you use purlins, you will easily see that you are screwing in the right place, especially if you choose to forgo the predrilling.All the available brands here require the screw to be driven in the valley, next to the ridge. They don't specify the underlayments you mention, nor rivets. There probably is a minimum pitch specified, but I never go less than 6/12, so the roof will shed snow.My own home is a saltbox, and the N roof is 30ft (near the maximum length for a single sheet) at 12/12. Last month we got 18" of snow in two days. The following day the snow shed all at once - quite and avalanche! No ice dams, no icicles, no leaks, no fuss. The way to go in snow country in my opinion!

1. 
   Guest_ | Mar 05, 1999 02:27am | #11

   *Steve,I agree. I've used silicone caulk at penetrations and dormer edges, and it sticks well to metal.Two thoughts as to the cause of the leaks:If the purlins were wet, then dried after installation, they will shrink in cross section loosening the screw so that the rubber washer is not compressed properly.If the screws were installed in the heat of the summer, and it leaks in the winter, the raised rib might contract in the the cold, also loosening the screw. This might be a small effect, I'm not sure.If the washers are not compressed at all, it's probably best to get up there and tighten them all up a bit some weekend.A word of warning based on my own stupidity:I was on a 6/12 metal garage roof that had several large branchs on it from the icestorm of 98. No problem climbing up with a chainsaw. Cleaned up the mess while sitting on the ridge, and lowered the saw by rope. The roof was now slippery due to all the saw chips, but it was only 6' off the ground to a pile of leaves so I went for it. I did slip landing on my belly headup sliding toward the leaves, BUT my wedding ring caught a roofing screw and took all my weight. Had to cut the ring and my finger was a mess. To add to my stupidity, I had just read in FHB that month an article on wedding ring safety. Duh!

1. 
   Guest_ | Mar 05, 1999 12:22pm | #12

   *I've done a 9/12, 5/12, 2/12 and now a 4/12 pitched metal roof. Safety ropes is always a good idea, but on a CLEAN, DRY metal roof, 4/12 is a breeze. If you can avoid drilling, you also avoid the metal debris that easily scratches the finish. If you can locate your penetrations for chimney, vents etc. in the pans, and preferably close to the ridge, flashing and sealing will be much easier.David

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   Guest_ | Mar 05, 1999 02:16pm | #13

   *Stan:As you can see from the discussion installing a steel roof, like most construction tasks, has a lot of personal preference in it. Some of this has to do with personal technique and working style. BUT, one thing is sure: Get the manufacturer's instructions and follow them!In my knowledge there are people who swear the manufacturer is wrong and there is a "better" way. Sometimes they are correct. But most of the time not.If I think I have a better way I like to contact the manufacturer to check it out. Most of the time they are cooperative.A couple of fundamentals apply to most roofs: Use as steep pitch as feasible for the situation. Less leaks, better snow shed, better structure. I only go below 6/12 if required by the job. Use a tether system for safety. Use skip sheathing for garages and other utility buildings if permited in your area. It is fast, strong, and most of the time cheaper than sheet sheathing.Rather than us getting into a debate about our personal style I'd rather see if we can help confuse you any more. Questions?

3. 
   Guest_ | Mar 05, 1999 05:04pm | #14

   *Oops,Sorry. The correct address is http://www.mtlsales.com

4. 
   Guest_ | Mar 05, 1999 10:08pm | #15

   *Great advice Fred,It occured to me last night that partially screwing a 4/12 roof then finishing it off after insuring sheet alignment would be pretty easy to do. As I said, I usually am working on steep roofs, where you must keep weight on a teather simply to stick to the roof. I bet you can just walk around on a 4/12. So my concern about getting each sheet screwed down before you get on to the next is probably inapropriate for the 4/12 case. Sorry if I came off as pushy in my last post...Rich

5. 
   Guest_ | Mar 07, 1999 08:38am | #16

   *Rich:We have had a good conversation. But I think the guy with the original question has left us. Wonder if we did him any good?

4. 
   stan_ | Mar 09, 1999 04:18am | #17

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   Hey guys I'm still here, thanks for all the input, not much on the framing, the guy down the road said he used common 24' trusses and only spaced spaced them 4' o.c. he said they didn't have to be 24" o.c because of the purlins being every 24" any comments??? I live in S.W. Ohio where we only have moderate snow loads

1. 
   stan_ | Mar 09, 1999 04:19am | #18

   *Hey guys I'm still here, thanks for all the input, not much on the framing, the guy down the road said he used common 24' trusses and only spaced spaced them 4' o.c. he said they didn't have to be 24" o.c because of the purlins being every 24" any comments??? I live in S.W. Ohio where we only have moderate snow loads

5. 
   Guest_ | Mar 09, 1999 08:25am | #19

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   Hi Stan,

   Unless you are using pretty thick gauge metal(I'm guessing thicker than 26 gauge), purlins on 4' centers spaced 2' apart might be stretching things.
   What size of truss/purlin spacing and purlin size does the manf. reccomend?

   Good health, Weogo

1. 
   Guest_ | Mar 09, 1999 12:33pm | #20

   *Stan:I really don't want to appear peevish; but your span question will be answered by reading the manufacturer's instructions.I just looked up your question in the BHP instructions and your proposed dimensions would be a no-no to them. They want rafters/trusses no more than 24"OC and either solid sheathing or skip sheathing at no more than 24"OC. Don't have any other instruction books quickly at hand.They also call out type of fastener(screws), screwing schedule, and installation details.The instructions are free from the manufacturer.

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   Guest_ | Mar 11, 1999 05:38pm | #22

   *Pre-drill the sheets on the ground, 5 or 6 at a time laid on top of each other, and you'll end up with such a precise screw pattern that when people look along it diagonally they'll be impressed that every screw lines up perfectly... no matter how good your eye is, you'll never achieve the same effect by screwing it down as you go along, and it also makes things go much faster. Also, do the 3-4-5 hypotenuse and get the rake straight, otherwise you'll end up with little steps along the edge. No need to leave them loose and go back later and get them straight, sounds like a huge hassle to me in comparison with just getting the first sheet right the first time. Good luck!

6. 
   stan_ | Mar 11, 1999 05:38pm | #21

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   Going to be installing my first steel roofing on a garage in a couple of weeks. It's a 4/12 pitch. I've never even seen one put up before. any suggestions or advice on framing or laying the steel???