Looking for best way to patch metal roof

[stevenf]

shvl73, What are "stitch screws" and where would I find them? Purlins, HaHAHooo you gotta be kiddin this is not a thing of beauty it was built with scrap lumber and material from old forts and army bases much of the lumber used has Fort Bliss stenciled on it from old packing crates and the guys that built it didn't seem to be to concerned with what is right or normal in the building industry. Roof rafters every 24 to 30 inches no purlins and many of the rafters were put on upside down like against the grain so they bow down in the middle plus they didn't use any real bracing or any sort of truss design just 20' long rafters nailed on the top and bottom with a boards nailed between them about halfway up to keep the spacing. The only good thing about the house is its not in tornado alley or it would have been in Kansas by now one piece at a time.
Steve

 

[EddieWalker]

stevenf, I will tell you my experience... maybe some of it will apply to your situation.

We build our house 20+ years ago and I got a metal roof because I wanted it to "last".

Well, the idiots that screwed the roofing down put the screws (yes, built for the purpose with washers under the heads) in the VALLEY of the material, not the PEAK of the corrugations. Corrugations are flat on top. I was distressed at the time but was assured that "that is the way it is done." Bull.... I've visited numerous countries in latin american rain forests... THERE they are smart... put the screws on top of the corrugations, not the bottom. As a result in our case, as the screws backed out of the underlying wood because of heat/cold/time, they began to leak. Lots of leaks.

If your roof leaks, it's not from fastening the metal in this manner. You have to screw the roofing into the purlins in the valleys as this is where it makes contact. You also need at least two screws at each purlin to make it secure. I prefer three. The only way to get this done is to screw them in at the lowest point where you have direct contact with the purlins.

The place where the metal overlaps can cause a leak if it's not screwd together, and on shallow roofs, it needs to be sealed as well. A 1:12 and 2:12 pitch roof needs sealing. Above that, you should have enough flow to keep the water from getting over the lip.

The overlap is screwd to the metal below it, but not into the purlins. You only want to keep the seam tight. If you screwed all the way into the purlins from the tops of the metal, you will deform it and create leaks.

If the overlaps are not screwed together, it will leak. Another common reason for leaks is the screws were overtightened. The rubber gasket needs to be snug and bulged just a very small amount. Take a look at them and see if they are cracked or squeezed down real tight.

It's rare today, but in older aplications, the screws themselves were bad. They rust out and create leaks.


Steve.

I'm not a fan of pathing leaking roofs unless it's just one area. It sounds like your whole roof is junk and needs replacing. calking and sealing will only last for a very limited time. If there is any movement in the metal panels, it will leak all the sooner. Since your roof was nailed on, not screwed, it's very likely that there is considerable movement. All your doing by calking or putting a sealer over the roof is spending money, burning calories and wasting your time.

If you need something right away, then save you money and energy and get a large tarp. They work well and will solve our problems for the next year. They are ugly, but they work.

The price you quoted for the roof is extremly high. Go to www.muellerinc.com and price out the materials on there website. Figure out how many sqares your roof is and it's easy math. A square is a hundered square feet. Depending on your pitch and roofing features, like dormers, gable ends, hips and valeys, will dictate allot in the number of sqares you need. A one thousand sqare foot house does not take ten sqares. More like 12 to fourteen.

Putting on a metal roof is a pretty straight forward project very similar to putting on siding. The hardest part is dealing with the heat. Work in mornings and evenings and it goes pretty fast. Steph and I did put all the metal on our house in two days. Then the trim took another week, but that had allot to do with how hot the roof got while standing on it. Your feet will literally burn when it gets to a certain tempature.

Fix it right and forget about it. Fix it wrong and you'll never stop messing with it.

Good luck,
Eddie

 

[texasjohn]

Eddie,
I understand what you say. And your theory is good. All I can say is that it didn't work in my case... lots of places, for whatever reason... too tight screws, insufficient number, bad rubber under screws, whatever..... leaks are clearly at the screws in the valleys where they have backed out of the underlying wood and stick up 1/4 inch or more from heat/cold movement. The overlaps are screwed at the peaks, as you indicate should be done. They have neither backed out nor do they leak.

My opinion is that if properly done using long screws and just barely snugging them up on the peaks without deforming the metal, then the water would run down the valleys which would have no penetrating holes at all. Hey, they do it in latin america that way, with completely "unskilled" labor.... and it works. I just know I'm really p.... that a roof I paid for and expected to last for 50 years leaked in 10 and none of the extra moeny I paid for construction insurance nor the builder covered it or owned up to poor install workmanship... it leaks, it shouldn't, I get to mess with it regularly, or put on another metal roof.

Glad that you have such a good hand to assist with your roofing tasks. I don't. Am wondering... can I install another metal roof over the existing roof... screw into it? The roofing pattern I now have is no longer available, thus would be a different ridge/valley pattern.

 

[ocaj11]

John,

Have you tried to get longer screws to replace the screws that are pulling out on you? It sounds like the screws they used are either too short or too thin. I'm just throwing out ideas, but it would seem to me that longer screws with wider threads would bite into your wood purlins better.

We just put up a 40 x 60 metal shop two years ago and we used metal purlins on the roof and wood on the sides. I don't expect the roof screws to back out of those metal purlins, but I wouldn't be surprised to see the sides back out. We screwed the metal down in the valleys and didn't add any screws on the overlap since we have a 4/12 pitch.

 

[shvl73]

shvl73, What are "stitch screws" and where would I find them? Steve

Stitch screws are short with a wide thread for fastening metal sheet to metal sheet. Ask for them at a lumber yard that sells metal roofing. I don't think anyone at a box store will have a clue.

 

[shvl73]

It's rare today, but in older aplications, the screws themselves were bad. They rust out and create leaks.
Eddie

Unfortunately it's not rare at all. A widely sold screw for roofs is just electroplated prior to painting. The paint will always chip to some degree on installation exposing inferior rust protection to the weather. The panel can commonly outlast the screw. Your best bet on a new roof is to insist on a screw with a galvalume head (painted if desired) or one with a stainless cap (also painted if desired). For exposure to a salt spray enviroment there is also a stainless steel screw.

 

[shvl73]

Eddie,
I understand what you say. And your theory is good. All I can say is that it didn't work in my case... lots of places, for whatever reason... too tight screws, insufficient number, bad rubber under screws, whatever..... leaks are clearly at the screws in the valleys where they have backed out of the underlying wood and stick up 1/4 inch or more from heat/cold movement. The overlaps are screwed at the peaks, as you indicate should be done. They have neither backed out nor do they leak.

A common result of overdriving or stripping out the screw is having them pop. Properly driven with a low rpm drill or screwgun should snug the screw in the flat expanding the neoprene gasket flush with the washer under the screw head.

 

[texasjohn]

Good ideas all noted above... I've tried:

Longer screws... nope... since the leaks are very slight at first, the wood holes roted and in maybe 40% of the cases no longer "get a grip".

I haven't tried stich screws... might be that the wider threads would be helpful.

Some of my screws were rusty on top, but that wasn't causing the leaks.... the backing out was the problem, not discovered until dry rot of wood had occured. They may have been overdriven or stripped when installed... I dunno... who checks the screws on the metal roof of a new home when there are so many other things to do at build/close/move in time.. and,

"experience is a hard school, but some fools will learn in no other"

So, my net is... when installing on wood purlins, if ever I do it again, I'll put screws on the peaks, use very light torque to avoid overtightening and deforming. On this I will insist, even if I have to do it myself!

The 40X60 metal building that I just put up has metal purlins top and sides and metal was installed with torque screwgun that slipped when proper torque was applied. Yes, the valleys were used, but with metal purlins there should be no problem.. I hope... Installation was done by American workers that have installed hundreds of buildings, worked cooperatively and productively together for several years, worked very safely and carefully in all aspects of the install. I was there the entire time the install was going on and never saw then get excited/mad/take shortcuts. I don't know what more I could have done to assure a quality install of the building. Time will tell if I got what I paid for.

 

[riptides]

Man I felt your pain.

I sucked it up a few months ago and replaced my entire 100+ year old metal tin roof. Put new metal on.

Got tired of the bucket thing.

No help I know, but there it is.

-Mike Z.

 

[shvl73]

Good ideas all noted above... I've tried:

Longer screws... nope... since the leaks are very slight at first, the wood holes roted and in maybe 40% of the cases no longer "get a grip".

I haven't tried stich screws... might be that the wider threads would be helpful.

Some of my screws were rusty on top, but that wasn't causing the leaks.... the backing out was the problem, not discovered until dry rot of wood had occured. They may have been overdriven or stripped when installed... I dunno... who checks the screws on the metal roof of a new home when there are so many other things to do at build/close/move in time.. and,

"experience is a hard school, but some fools will learn in no other"

So, my net is... when installing on wood purlins, if ever I do it again, I'll put screws on the peaks, use very light torque to avoid overtightening and deforming. On this I will insist, even if I have to do it myself!

The 40X60 metal building that I just put up has metal purlins top and sides and metal was installed with torque screwgun that slipped when proper torque was applied. Yes, the valleys were used, but with metal purlins there should be no problem.. I hope... Installation was done by American workers that have installed hundreds of buildings, worked cooperatively and productively together for several years, worked very safely and carefully in all aspects of the install. I was there the entire time the install was going on and never saw then get excited/mad/take shortcuts. I don't know what more I could have done to assure a quality install of the building. Time will tell if I got what I paid for.

In this instance, I think I would apply a back-up piece of metal under the roof panel and use a stitch screw to seal the leak. While it won't tighten the panel to the purlin, it'll fix the leak and if not a widespread issue, shouldn't affect the structural integrity of the roof as a whole. Ensuring you get a proper job in all aspects of constuction is nearly impossible. I think we've all been there unfortunately. What we think we're buying and what we recieve is all too often, two different things. Sometimes they're expensive lessons and sometimes just annoying, but either way it stinks.