Standing Seam vs. Lap Seam

[ecarecar]

I have a small, low-slope metal roof of about 300 square feet. What are the advantages and disadvantages of a standing seam roof versus a lap seam?

[Bob Morrison]

Standing seam has no exposed fasteners and should be considered a permanent roof if properly installed. Laps seams have gasketed fasteners that can leak over time and this causes rusting of the steel sheets.

Go with standing seam!

[ecarecar]

You can use non-gasketed fasteners and solder them over.

What about wick>>

[Dan Deckert]

Standing seam if you can afford it. NO SOLDERING ON EXPOSED FASTENERS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Dan

[Bob Morrison]

Dan:

I agree absolutely! Soldering of fasteners does not seem like one of the better thought out ideas.

[Dan Deckert]

FASTENERS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The OP made some mention of soldering. I've NEVER HEARD OF SUCH in 30 yrs. of putting on metal roofs. I 'suppose' it might apply to 'some type' of copper roof but it seems wierd to me. The new Kynar paints over galvalume substrate would never allow adhesion anyway much less with the Kynar painted zinc chromate srews with neoprene washers.

The newer SSR's with factory installed mastic will prevent wicking if the SSR is applied correctly. Even better are SSR's with a mechanical seamer run down them to roll & fold the seam. Damn near bullet proof. I have, however, installed an SSR roof with a seamer and had leaks. It was because the factory had failed to apply enough mastic to seal the lap. Interestingly enough it was a Butler Bldg. of whose product (roofs anyway) I consider one of the best.

Dan

[RicodJour]

It is possible to directly solder copper nails on a copper roof, but it's a bit of a hack. The preferred way to achieve that end is to nail through a copper clip, fold the clip over the top of the nail and solder the perimeter of the clip.

R

[ecarecar]

Well, you should think about it.

[ecarecar]

[Dan Deckert]

Seems as though ecarecar is in severe contrast to our opinions and experience, not to mention ADVERSLY CONTRASTED.................LOL Ya suppose a 78 yr old guy is ticked off here? 60 yrs. of roofing and 18 yrs. to be old enuf 2 do the work???? Dan

[RicodJour]

Which makes this more curious:

I'd like to hear his reasoning and procedure for directly soldering the fastener.

R

[Bob Morrison]

Okay, I thought about it for about 5 seconds and have come to the conclusion that soldering roofing fasteners on a steel roof is one of the dumbest ideas I have ever heard of.

[ecarecar]

No. That's all wrong.

The process comprises soldering sheet stainless steel together then driving nails in to hold it in place and soldering the nails. It produces an excellent roof.

[Bob Morrison]

That may be, but one doesn't need to go to that much work to get an excellent roof. Not to mention, most steel roofs these days have a baked on finish that would make soldering them together virtually impossible without ruining the finish.

A standing seam roof is only marginally more expensive (25% or so) than a conventional lap seam roof. This seems like a small price to pay for what is essentially a permanent roof.

As others have pointed out, a field rolled seam is usually best, but snap lock seams work pretty well too for residential applications over a solid sheathing substrate.

[RicodJour]

Okay, now you've lost me. I've done a fair bit of copper and lead-coated copper roofing. When sections are seamed and soldered, all of the nails and copper clips/cleats are concealed. There are few if any exposed fasteners. Why would you have exposed fasteners, essentially creating a new metal roofing technique, when the existing copper roofing techniques have centuries of performance standing behind them? You obviously could do the same thing with stainless steel.

The concealed clips/cleats are what allows the metal roofing to move with thermal expansion/contraction. By nailing it down directly you're just building in weak points in the roofing. If your soldering job is impeccable and the solder doesn't fail, the thermal expansion cycle will elongate the nail hole and the nail will lose a significant amount of its holding power. This is a critical flaw in high wind areas. The roof will fail at those points, it's just a question of when.

The fact that in your experience you haven't had any failures doesn't mean much in this instance. A stainless or lead-coated copper roof should outlast you, your children and their children if done correctly. It's like being in the fiberglass roofing business and saying that you've been installing them for 4 years, so there's no problem with your installation. Doesn't fly.

R

[RicodJour]

It's our own fault. I didn't keep track of the posting history. I thought he was weighint in with some expertise on the OP's question, so I replied. I hadn't noticed that he is the OP.

Gee, maybe we were "set up" - maybe he's checking to see if we know what we're talking about. So either he's a troll, has trollish tendencies, or, from the comments, has no basis to determine if we do know what we are talking about or not.

R