Waterproofing metal roof

[Hghgrad]

The roof on my shop has seen better days. The picture is from long ago, and the roof has a little rust on the west face now. It leaks at the seams of the low pitch, leaks at the nail holes holding it down.

I've got most of my stuff distributed so it doesn't end up soaked, but it seems some new random leaks have come to light recently.


Short of a new metal roof, what are the options? I see some roof coatings available at the big box stores, but I'm not really sure what I'm going to need.

 

[tjdux]

My dad has had some luck with the silver colored rubber emulsion coating on some metal roofed buildings ar his farm including a grain bin. It is cheaper than a new roof and helps but may not solve everything. And he only had small nail leaks and it got 90% or maybe more of them but your situation sounds a bit worse than his already.

From the photo it looks like that building has almost no slope on the roof at all on the sides. I always thought tin needed a little more slope than that to keep the water moving over it at good enough speed to not puddle and get under seems and nail holes. Also if you live in a freeze/thaw climate any water sitting on the low slope will speed up the leak process a lot.

The small portion of the building looks near minimum slope for metal in my opinion and the lean too portions on each side look almost flat from the arerial photo.

Not the solution you want to hear but if you do replace the metal I would recomend removing the entire roof off the whole building and modify the rafters to have 1 pitch across the whole roof to increase the slope on the flat parts. It wouldnt be a crazy huge expense compared to the metal anyways and should help a new roof last much longer making your nice building that much nicer.

Emulsion coat = possible long term bandaid

New roof with better slope = probable permanent fix

Both are lots of work, emulsion is probably cheaper but requirez walking on an already damaged roof which may cause the emulsion to never seal as the tin flexes from walking on it.

Also next time use screws. Nails are pretty much proven to fail over time and screws are far less likely to leak. I personally run my screws down the ridges but to each his own.

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[matt_i]

You could probably buy some time with clear 100% silicone caulk applied over the region(s) where you think leaks are developing. Thats a pretty standard shingle roofing problem solver especially if you have nails or visible light leaks. I think you could get it to bond to the metal with some cleaner like non-chlorinated brake cleaner.

 

[Bondo]

Ayuh,.... Look into Geocel Tripolymer 2300,...

It comes in caulkin' tubes, or a thinner mix in a paint can that can be brushed on,....

 

[Hghgrad]

I was thinking about pulling the nails and screwing the panels down again. There's a 1 pitch on the side wings of the building, and I had considered trying to raise it if I was going to re roof completely. They're just 2x10s sitting on a beam on the inside of the structure. It probably wouldn't take a whole lot to raise it a few inches to help out if that would fix the issues.

I was thinking I could get a few years out of a paint on coating, which would give me the time to get the cement floor in the bigger barn and turn that into my workspace. The small barn already has cement, so it was the only option when I bought the property.

 

[Franz1.0©]

Step 1 is always standing under the roof on a Sunny day and looking up to see how much it resembles a strainer.

If it doesn't look like a strainer proceed

Polymeric roof coating is a wonderful thing, as long as it stays on the roof.

Since you're in Detroit area, you're blessed with both freeze & hot cycles + Acid rain. All of that + the condition of the roof itself = 3 to 5 years of effective life.

Thanks to the climate protection people most of the elastomeric coatings you can buy are now water based. That alone means poor adhesion and shorter use life.

Clean is a big factor in adhesion, if the roof is dirty, wash it with Dawn Dishwashing soap.

If it was my roof I'd hunt up some good old fashioned FIBRATED roof coating that is NOT water based, and some fiberglass screening.

Blow the roof off with a leaf blower use screen to "patch" over perforated areas with roof coating for both adhesive & topcoat, and then you'll get 10 years out of the job.

 

[EOC_Jason]

Some professional roof coatings guarantee 10 year... and is supposed to be cheaper than roof replacement...

 

[cdeer001]

As seen on TV - FlexSeal

https://www.flexsealsale.com/flxsl/...8&otsrid=144726f0-ce07-457b-be13-5287b3b7626d

 

[Hghgrad]

There's no holes in the roof besides the nails. I guess I'm going to have to get up there with a box of caulk and go to town.

 

[tjdux]

There's no holes in the roof besides the nails. I guess I'm going to have to get up there with a box of caulk and go to town.

That may work awhile but a few freeze thaw cycles theres a good chance water will find it way around the silicone on the rubber seals. Hooefully its enough to last til you can replace or more long term situation

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[Hghgrad]

I'm hoping for a couple year solution. I need to get a floor poured in the other barn and move everything over there. I'll have room for a lift and whatnots over there.

 

[EOC_Jason]

If the roof isn't rusted out around the nails you could pull them out and put some over-sized screws in with the neoprene gaskets.

 

[flat tire]

this will stop your leaks.
my home place has a standing seam metal roof that was put in 1947-48.the original roof is still on there today. I would paint it every other year with :
Fibrated Aluminum Roof Coating

Johns Manville Fibrated Aluminum Roof Coating is a highly reflective coating made of pure aluminum pigment flakes blended with selected, refined solvents and reinforcing fibers for heavy-duty service.

Fibrated Aluminum Coating is used as a protective, reflective coating over built-up, SBS and APP modified bitumen, metal, corrugated and tin roofs.

 

[theoldwizard1]

Caulk until you can do it right. New roof !

 

[matt_i]

The stuff that suprised me the most was the no-name gutter sealant that I got at Allied Building Mat'l. It was like a silvery color, tacky as anything, could not get off hands, and dried pretty fast. Not sure how long of a life (yet) but it is NOT water based. The absolute best may be the urethane they adhere car windshields with, seriously strong and nothing short of MEK will cut it. Skins in 5 minutes. Nasty stuff but awesome at its job.

 

[stingry]

this stuff
http://www.homedepot.com/p/Henry-4-75-Gal-555-Premium-Aluminum-Roof-Coating-HE555019/100094951

or similar product. Used it on a farm shed similar to yours. Pull the nails that have popped and replace with longer ringshank nails or screws. Mop this stuff on with a small push broom and you're good to go. Been five years now and is still in place and no leaks yet!!

Cheers
Steve

 

[Hghgrad]

I read the reviews on that stuff earlier. It looks like something I can give a try when the weather warms up a little bit around here. Thanks for the input.

 

[XRlifer]

if the roof isn't rusted out around the nails you could pull them out and put some over-sized screws in with the neoprene gaskets.

this!!

 

[tjdux]

I read the reviews on that stuff earlier. It looks like something I can give a try when the weather warms up a little bit around here. Thanks for the input.

Thats the same style of stuff my dad had some luck with on his farm buildings. And they are right about it being thick as hell and dry fast and even gasoline has a pretty hard time cleaning it off your hands.

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[Capt Chrysler]

We use a Conklin product. Insurance company liked it. So no problems there. I think it has a 15 year warranty.

 

[kelpaso1]

As seen on TV - FlexSeal

https://www.flexsealsale.com/flxsl/...8&otsrid=144726f0-ce07-457b-be13-5287b3b7626d

Has anyone ever used this product? If so how good did it work?

 

[tjdux]

Has anyone ever used this product? If so how good did it work?

You may want to atart a new thread for that question. No clue about the product. Seems like great stuff expanding foam or regular silicone is what i would choose based on the project at hand tho.

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[Bwestfla]

Hey guys...I have been a lurker getting ideas for my garage when I ran across this thread and interestingly enough I work for Henry and ran their product development team for many years and would be happy to help answer questions.

For your roof I would recommend a silicone roof coating rather than an Aluminum. The Aluminum is good at protecting an existing watertight roof or encapsulating rust but not a great roof restoration product when you need to make it waterproof. If you are deadset on the Aluminum, you will want to treat the fasteners first, then seal each seam with asphalt emulsion and reinforcement mesh. Than coat entire roof in Aluminum coating. Buy a good one that is rubberized and is fibered like Henry 869. Don't waste money on cheaper ones as they turn brown in a year or two.

I would strongly recommend the following if you are going to keep the property.

http://us.henry.com/roofing/reflect...-cool-silicone-white-roof-coating-high-solids

or

http://us.henry.com/roofing/reflect...ngs/pro-grade-988-silicone-white-roof-coating

The former is what you would get from HomeDepot and a great choice and the later is what you would buy from a specialty roofing yard. Either way, the most important part is treating the fasteners and joints first, then 2 coats of silicone....you will have a 20+year roof after that. We do TONS commercial properties like that. Also, these silicones are NSF certified meaning the rain run off is safe. Nice bonus!

Best of luck....now back to planning my 30x35 garage build