Would it be feasable to build with osb walls & a steel roof?

There would be many advantages to this including cost & time. Eliminate furring out of the walls for electrical, eliminate the need for a crane to place the roof panels & maybe reduce the size of the ridge beam. The steel roof could be the finished roofing material and the facia thickness would be thinner than an osb sip roof. I can think of many other advantages to doing this, but would like some feedback to see if this is doable first.

I may even offer my house as a test project for this if people think this idea has merit. The house I'm planning is a simple 28" x 48" rectangle with attached 28" x 28" garage. One simple rectangle just to keep time & costs low.

Henry 

Your roof could be built with steel trusses, ply deck and then add metal roofing. Or use wood trusses (Cheaper )with same metal on for the roof. Metal roofing works great in snow climates. Sips take extra time to run electrical and that has to be factored in. I have seen SIP walls furred out to accomodate the electrical runs. Plan your Plumbing vents up interior walls. You can sometimes use a "Studevent" for the kitchen sink and dw.

Hope this help.

Thanks terrymod.

I want to use a sip roof because the living/dining/kitchen will be vaulted & a loft above the other areas. (2 baths/master bed/mudroom)

Most drains & some electrical will be burried in the slab, and I want all vents out the walls. Some stuff will be run thru the floor joists of the loft.

Costs are all subjective to design. One can easily make a product claim or do a $ by $ analysis by product but it is all a function of design.   I've seen flat roof designs cost significantly more money with stick / metal framing than with SIP.  Also contrasting trusses vs. stick built.  The same can be said about analysis of energy demands on the basis of fenestration, local & orientation. When building with an alternative building system a good designer from this region will not only save you time in getting the desired design but also design effectively with the appropriate materials. Would you buy a Swamp cooler for a home built with high humidity?  Or install a solar water heater for home heat in an area dominated by heat?  Well people do that very thing, they buy some plans out of a magazine or from an old "Stick frame" developer plan. These have been designed around those inferior systems.

Find a good designer that can model your building and do energy analysis. Don't get too hung up on systems, just let (him / her) know what you are considering. Evaluation software like Green Building Studio, Ecotect & Modeling Software like Revit are great ways to know if you truly are getting sustainably design system. They allow you to see your home / building, evaluate a base line energy use against alternative systems and even provide you with comparable carbon models to see if you are truly achieving what your goals are.

Jeremiah from Kansas
bullfrog4d@gmail.com
if you have any questions or want any referrals, i know a few people here in the mid-west.

Henry,

Its not a bad idea using a metal panel for the roof where most of the potential moisture issues are. Mixing wood construction with metal construction can be problematic for some contractors not familiar with both material installations. The metal roof panel will still have to have drywall on it. If any ceiling mounted electrical fixtures are needed on the ceiling it would be best to furr it out. The metal SIP roof would have pre-finished exterior soffits. That could definately be cost effective. Overall I think it is a good idea.

I just had this same thought earlier today.

This would be very interesting because it would save you roofing costs and because the metal SIPS can span long distances, it could free up your floor plan.

For some reason I have an irrational block against metal SIP walls but not metal SIP roofs - maybe because roofs are replaceable.

What do you do when it is time to put on a new 'roof'? Is it cost effective if you have to replace the panels every X years?

tlynch;

when it time to replace a roof on any system you replace the roof only , not the trusses, rafters etc.

Its the same with steel or OSB sips , as they are the structural substrate and thermal component.

Chris -

I was under the impression that Henry Hodgson was suggesting to use metal SIP panels for the roof with no additional sheathing, just taping the seams, and leaving the SIP exposed, as a low cost option.

Todd

Todd;

it is possible to do that and we have done it as well, for economy, metal sips can have a dual purpose, we did it on our own warehouse too.
But there is no beauty to an exposed metal roof or wall, they will require attention to the tape every 10 years
the roof has to be simple to accomplish it (no valleys, dormers,etc.)
many refrigerated warehouses have been left exposed for years, walls and roof, with proper maintenance will last for many years more. I prefer to rely on the metal sip as a secondary water barrier, for aesthetics and ultimate longevity.
if it was a shed, garage, warehouse, etc, they are just fine

Thanks Chris. Agreed, not the best looking option, but I was just exploring Henry's idea.

Have you guys ever considered creating a roof panel that was more aesthetically appealing maybe faux standing seam or corrugated that could be used as low cost option for home building? Even as an option for stick framed homes.

15 year warranty then the whole thing gets ripped off and replaced every 20 years or so?

Todd;

 

its been talked about, but the valleys are problematic due to the thickness of the panels

Chris, I put a 22 gauge standing seam, steel roof with a Kynar coating on my house, and they were telling me that the 22 gauge material (with proper maintenance) should last for 75 years. And it is an amazingly beautiful roof. I can see where valley's could cause problems with an all-in-one roof panel, but, assuming that problem could be overcome, it sounds like a very attractive roofing option.

Especially because the spans of metal sips are so great it would open up the floor plan and could save cost.

If the panels were factory cut the install would be very quick.

Dick;

it is the same coating on our panels, I think 75 years is conservative.
There are many old farmhouse roofs that old with coatings less intricate

Todd;

shipping ,handling and installing a finished roof product that bulking without damge , is challenging

I am not a builder so I can't compare the cost of the standard method of framing a roof, insulation, and a standard metal roof versus a system like we are proposing. It might easily cover shipping. Even if material cost were equal, time would be saved and the process would be far simpler. But I do see this as an door through which SIPs could move into the mainstream.

The cost of placing a cosmetic roof over the steel SIPS structure is not that great in the scheme of things.

I am considering a metal SIP flat ceiling on the concrete home I am designing.  It will be covered with a metal or wood truss roof.

How long can metal Sip spans be?  Can they Span 20 ft without support?

It all depends on the use;

a 12" steel sip will span 41 feet @ L/120 and a 20# load

wildblue,

As a rule of thumb a 6" thick metal panel can in "most common/average" load conditions and "conservatively" clear span around 16-17ft. This is the figure I have in mind when I am first evaluating and designing a metal panel structure. I then go to load tables to for specific spans based on local requierments for snow or wind which will then increase or decrease this figure by a few feet.