Nice site I ran across showing many pictures of Metal SSIP homes under construction.

http://www.elementbuildings.us/phot...s_1500.php
http://www.elementbuildings.us/photos/res_2500.php
http://www.elementbuildings.us/photos/res_5000.php

http://www.elementbuildings.us/blog...the-frame/
http://www.elementbuildings.us/blog...he-garage/
http://www.elementbuildings.us/blog...m-the-air/

Should provide some nice visual information.

I wonder how well the cut edges of steel SIPs hold up after 20 years of salt laden air floating in from the ocean.

G90 coating should hold up fairly well.  However, Galvalume and Galvalume Plus might do better since aluminum is recommed instead of steel for coastal regions except when in contact with concrete.  See http://www.englertinc.com/blog/01-2...-projects/

There should be no cut edges exposed directly to weather in a Metal SIP home. Extra precautions should be taken in a Marine environment like stainless steel screws, finish underlayments, flashings and weather tight chalk & paint jobs. Just like any house by the coast.

I'm specifically concerned about cut metal edges and screw holes sealed up inside the wall. No matter how well it is sealed, I expect that a little bit of salt air will get in. Maybe even while it is being built. Salt + high humidity + tiny areas of unpainted steel....

Posted By jonr on 31 Mar 2014 05:37 PM
I'm specifically concerned about cut metal edges and screw holes sealed up inside the wall. No matter how well it is sealed, I expect that a little bit of salt air will get in. Maybe even while it is being built. Salt + high humidity + tiny areas of unpainted steel....

Just think about all the tens of thousands of wood framed homes along the saltwater coasts with unpainted galvanized straps and clips with steel nails holding down those wood trusses held together again with unpainted galvanized truss plates,
all exposed to the direct salt air thru the vented soffit ,
I'll bet there all disentegrating as we speak
:)

Areas with intact galvanizing are not the question. Just a couple of weeks ago I was 1) looking up at steel fasteners rusting away in a beachfront open air restaurant (age and material unknown) and 2) talking to a builder who was slapping paint everywhere there was a cut or weld interrupting the galvanizing (no idea if he knew what he was doing).

Looks like manufacturers recommend stainless steel or aluminum for < 100 meters from breaking waves. And that's for roofing that isn't so hard to replace.

Those projects were done by Scott Bartels of Florida Alternative Building Systems. He and Chris Kavala are two of the most knowledgeable metal SIP builders in the country.

Their project pictures showing the structural steel support members for the hips and valleys is certainly a well thought out system, this is why I posted the links to share, as many have not seen complex builds with metal SSIP.

In my opinion the cut edge will rust and then stop rusting due to the rust basically sealing the cut edge like Cor Ten steel, and if there is no physical weathering action on that surface it will not rust any further. Exposed fasteners are a problem and can be replaced as needed.

For most homes they wont be located near the ocean ..... If their is a concern about the cut bare edges, paint them with a paint/epoxy spray sealant. Theirs not much else that can be done economically to an field cut bare metal edge to slow down the natural process of corrosion.

As for longevity Metal is Certainly Far superior than WOOD ....... its the next best thing to concrete!

Posted By jonr on 31 Mar 2014 07:51 PM
Areas with intact galvanizing are not the question. Just a couple of weeks ago I was 1) looking up at steel fasteners rusting away in a beachfront open air restaurant (age and material unknown) and 2) talking to a builder who was slapping paint everywhere there was a cut or weld interrupting the galvanizing (no idea if he knew what he was doing).

Looks like manufacturers recommend stainless steel or aluminum for < 100 meters from breaking waves. And that's for roofing that isn't so hard to replace.

Jonr,
the difference is in most cases SSIP's are covered with roof and wall claddings and not in direct contact with salt air, all panel cuts are capped off and covered with channels.
If one is real paranoid about the cuts they can be sheared instead of saw cut, the shearing prevents the exposed metal from rust.