Tag Archives: roofing materials

If You Think Red Iron Buildings Are Great

If You Thought Red Iron Buildings Are Great

Loyal readers, please join me in reaching way back to yesterday’s article espousing great benefits of PEMBs (Pre-Engineered Metal Buildings) aka “red iron” or “bolt up” buildings.

If you are planning a new barndominium, shouse (shop/house), shop, etc., and have decided a PEMB is your one and only answer – far be it for me to try to influence you to consider anything else. For those of you who are “on a fence” trying to make an educated choice, please read on. My comments are in bold.

Keep in mind 93% of all new residential construction is wood frame (either stick or post framed) and roughly 3000 all steel frame homes are built annually in America (this would include weld up, as well as light gauge carport type). While 3000 may sound like a large number – total single-family housing starts in 2019 were 888,200.

I gave a dozen reason yesterday as to why PEMBs are great, here they are (along with post frame notes in bold):

1. When working within defined standard dimensions high-tech engineering and design software simplify processes and make for efficient use of steel. For pennies per square foot of price difference, fully engineered post frame buildings can be customized to exactly meet one’s wants and needs.

2. As long as foundation bolts are properly placed and bolt holes are correct, no field structural steel cutting, welding or drilling should be required. Post frame is very forgiving – no cutting torches or welding required.

3. Building components and steel sheeting can be shipped from regional manufacturing and warehousing locations to minimize freight charges. Just like post frame.

4. Fully engineered buildings with third-party engineered foundation plans, simplify permitting processes. Fully engineered post frame buildings include foundation plans – no need to have to hire yet another engineer on your own.

5. Steel has a very high strength-to-weight ratio. Obviously footprint, height, roof slope and manufacturer will come into play, however an average weight per square foot for a PEMB shell seems to be roughly eight psf (pounds-per-square-foot). Fully engineered post frame construction takes advantage of this high strength-to-weight ratio by utilizing steel skin shear strength. Post frame also allows for easy application of alternative roofing materials (shingles and even tile!) as well as a plethora of siding options. And – an average post frame building shell weighs in at about eight psf!

6.  Once foundations are excavated, formed and concrete is poured, a contractor with proper heavy lifting equipment can erect a fairly significantly sized building fairly quickly. Post frame building shells can be erected without having to wait upon a slab-on-grade to be poured. They can easily be built on full, partial, or walkout basements, or have crawl spaces incorporated. They also lend themselves well to DIY assembly, without requiring heavy lifting equipment.

7. Fire resistant metal framing does not ignite. With addition of 5/8” Type X gypsum wallboard, steel furring and appropriate insulation options one and two-hour exterior wall fire ratings can be achieved. According to the National Fire Prevention Association (www.NFPA.org) 86% of all home structure fires are caused by cooking, heating equipment, electrical, arson or smoking – all of these being independent of what type of structural system is being utilized.

Fire retardant treated wood can be utilized where concerns for structural systems burning arise: https://www.hansenpolebuildings.com/2017/07/dricon-fire-retardant-treated-wood/.

Post frame buildings can also be designed with one or three-hour exterior wall fire ratings https://www.hansenpolebuildings.com/2012/03/firewall/.

8. Insects do not eat steel. Nor do they eat properly pressure preservative treated wood https://www.hansenpolebuildings.com/2020/09/pressure-treated-post-frame-building-poles-rot/

For those who are still not yet convinced, structural columns can be placed above ground: https://www.hansenpolebuildings.com/2019/05/sturdi-wall-plus-concrete-brackets/

9. With high-quality paint on a proper galvalume or galvanized substrate, steel roofing and siding require very little upkeep. Post frame utilizes this same steel roofing and siding (unless non-steel claddings are preferred).

10. Fully engineered, properly constructed steel buildings withstand damage from earthquakes, winds, snows, hail and other weather extremes as well as an equivalent post frame building. Any fully engineered structural building system will support climactic conditions as indicated on sealed plans. There is no legitimate claim for an excess capacity beyond what has been engineer certified.

11. Dimensionally stable steel changes little with temperature – in a variance of 100 degrees a 50 foot width building expands or contracts just under ½ inch. Steel does not change dimension with shifting moisture content like wood framing does. Wood, in service (within a climate controlled building) generally ranges in moisture content from six to 14%. Expansion and contraction of wood is greatest tangentially with common framing lumber changing dimension by a factor of as much as 0.00267per 1% change in moisture content. From average to maximum or minimum a 2×6 might vary by 0.059 (under 1/16th) of an inch. Considering all wood members of a structure are shrinking or growing at fairly similar rates, this is a non-issue.

12. Clear span steel buildings promise endless floor plan possibilities, with no restrictive load-bearing walls required. Up to and including 80 foot clear-span (in some markets greater) fully engineered post frame offers this as well.

This is a Test: Steel Strength

Once again, we hop in the “Way Back Machine” and visit what to some might be viewed as ancient history. Sometimes in life – to know where we are, it is important to know where we came from.

After selling my first post frame building business, M & W Building Supply, to Jim Betonte in 1990, I did some work for him as a consultant. One of the missions I was assigned to was to determine the shear strength of the steel roofing and siding being used on the pole buildings M & W was providing.

By having tested shear strength, the steel skin could be utilized structurally, much as plywood or oriented strand board (osb) is used. Plywood and osb have values which are published in the National Design Standards (NDS) for wood. At the time, limited testing had been done on steel panels, for shear strength. A testing procedure had been developed by the ASAE (American Society of Agricultural Engineers) Structures Committee, of which I was a member.

Alumax had a testing facility in Perris, California. Under the watchful eye of their then chief engineer, Merl Townsend, we constructed a roof assembly using rafters spaced every 12 feet (to simulate roof trusses), and 2×6 purlins on edge. On top of this, we installed the thinnest possible steel we could get in the marketplace – it barely made 30 gauge (.0127 of an inch thickness). The steel was attached with the industry standard #9 diameter one inch long screws.

Once constructed, horizontal loads were applied to the rafters, using hydraulic rams. The rams were set up so as allow for the amount of applied force to be measured.

As loads were applied to the roof, we had a surprise problem, which we had not anticipated. The one inch screws were pulling out of the framing – and not enough load had been applied to the roof to even make a ripple in the steel.

OK, problem numero uno solved – we replaced the one inch long screws with 1-1/2” long screws. This length of screw did not pull out.

Next cyclical loads were applied to the assembly, to simulate applied wind loads. As these loads were applied, we started to notice slots forming around the screws, in the direction of the load. The slots became long enough to be past the edge of the steel grommets on the screws. While this would not have caused a structural failure – it would be considered a failure by most building owners, as their roofs would be leaking!

Merl was one very smart guy. He designed a screw to solve both the pullout and slotting problems. This part was 1-1/2 inches long, with a #12 threaded shaft, which tapered out to a #14 just below the head. The larger #14 diameter, kept the slots from appearing as testing went forward. Merl’s screws are now featured as the standard part in every Hansen Pole Building with steel roofing or siding.

Viewing the testing was amazing – waves would appear in the steel between the roof purlins, several inches tall. When the load was taken off, the steel snapped back to flat. Eventually, a 9600 pound horizontal load caused the steel sheathing to buckle permanently.

From my previous experience in testing nail laminated columns, I knew we could only use 40% of the ultimate value (failure point) for designs. At the 40% point, there was not even the slightest ripple apparent in the steel roofing. The results of our testing have been accepted and are published in the National Frame Builders Association “Post-Frame Building Design Manual” Table 6.1 test assemblies 13 and 14.

These tested values are very comparable with those obtained from plywood and osb sheathing, so think of steel roofing and siding as performing like very thin, very strong plywood.

Don’t Get Tired, Get Roofed: Recycled Roofing Materials

Most alternative eco-friendly roofing materials, such as those which contain a high recycled content, are about three to four times the installed cost of asphalt shingles.  This is a hard sell for anyone, no matter how green you want to be.

There may be a reason to be optimistic for the future, however. Euroshiled Roofing’s EuroLite Slate is made from over 75% recycled materials – rubber tires! An average roof will utilize 600 to 1000 rubber tires. The installed cost of this material, which comes with a transferable limited lifetime warranty (non-prorated for the first 50 years), is actually comparable to the installed cost of premium asphalt shingles. This is unprecedented as far as eco-friendly roofing goes.

How green is it?  Well, those recycled car tires are certainly saving landfill space.  And the shingles themselves are 100% recyclable.

The main reason this product is more affordable than other recycled roofing options is it installs quickly and easily. It goes down in 40” x 17” panels which handle and install similarly to asphalt shingles, with some special design perks which are supposed to make it even easier.  Moral of the story is this isn’t a difficult roof to install and if your contractor is inflating the cost beyond what he would charge to install asphalt, then you may want to press him a bit on why.

Plus, it looks good.  Even up close it looks like slate, although it is much lighter.  From street level you’d have a real tough time telling the difference between recycled roofing and genuine slate.  The shingle is available in grey, black and brown.

The downside is the product is made in Calgary, Alberta, Canada with limited distributorship in the US.  They will ship product for a single building, but this could get mighty expensive.  Hopefully the company will secure more distributors in the US soon, because judging from the consumer searches for roofing material there is a healthy demand for eco-roofing.