Tag Archives: 26 gauge steel

An Alternative to a Very Flat Roof Extension

An Alternative to a Very Flat Roof Extension

Reader BOB in SANDPOINT writes:

“Hello we want to add a patio / work on car / whatever, extension off the front of an existing shop with a metal roof – joining the existing metal roof with the metal roof of the extension with a sort of pitch break. The challenge is the 10′ height of the existing roof and only having 18″ drop to the garage entrance. Ideally we would extend out about 14′ but I am thinking the extension roof would not be steep enough. I was planning on installing a pitch break joint where the two roofs meet (but not having an actual difference in pitch – or as little as possible).also, being in Montana we do have significant snow. I know with the pitch issue of only having the 18″ drop – and the target of 14′ I will have to compromise but trying to figure how much and where.”

Mike the Pole Barn Guru says:

Well Bob, you do have some challenges and are not the first person to have them.

Most steel roofing companies will not warranty their product on roof slopes of under a three in 12 slope (3/12). At very least, doing a single sloping roof this flat, in snow country, poses a myriad of challenges – some of them you have already considered. Rafters and purlins for such an extension will require them to be engineered to support the weight of snow sliding off steeper main roof. Ponding is a real concern, as ice and snow will build up and not slide off. You should probably look at using 26 gauge steel with ribs higher than what is on your existing building (meaning steel profiles will not match) and perhaps installing over solid sheathing – either OSB or plywood, with 90# asphalt impregnated (felt) paper or a synthetic water and ice shield below.

If you are thinking this is sounding expensive or perhaps impossible, there is an alternative option.

Your extension roof could be done as a reverse gable – meaning you would not have height issues in front of your existing overhead door opening. This would also allow for snow to slide off to right and left of your extension, rather than plopping off directly into your line of travel in and out. We use reverse gables frequently, in new construction, to protect door openings from rain water or snow slide offs. Here is some extended reading for you: https://www.hansenpolebuildings.com/2015/07/reverse-gable-porch/

Concrete, Steel Gauges, and Skylights

This Wednesday the Pole Barn Guru answers reader questions about volume of concrete needed to support a 300lb sign, pros and cons of both 26 gauge and 29 gauge steel, and replacing skylight panels.

DEAR POLE BARN GURU: I need to know how to calculate how much concrete would support this sign at 10ft with a 6 inch metal pole sign weighs 300lbs. BILL in TACOMA

DEAR BILL: Required amount of concrete will be based upon design wind speed and Exposure where sign will be placed, height of sign above grade and surface area of sign. You would be best served to reach out to a local Registered Professional Engineer, who can provide a sealed design for you (may be required by your permit issuing authority as well).

 

DEAR POLE BARN GURU: For steel roof panels and siding, what are the pros and cons of both 26 ga. and 29 ga. panels? Do the 29 ga. panels have a higher steel yield strength (80 ksi)? TOM in SMITHVILLE

DEAR TOM: Cons of 26 gauge steel roofing and/or siding are added investment and lower steel yield strength (usually 50 ksi or less). For more thoughts on this discussion, please see https://www.hansenpolebuildings.com/2020/11/do-barndominiums-need-29-gauge-steel/

 

Skylight WarningDEAR POLE BARN GURU: We need to replace some sky light panels on one of our older sheds. The roof and current panels are on 12″ center ribs. Do you have sky light panels that will fit my building DAN in ALMA

DEAR DAN: Sadly you are now faced with deterioration issues coming along with fiberglass panels placed in roofs. We provide panels with high ribs every nine inches on center. I would recommend you visit with the ProDesk at your nearest The Home Depot, with exact measurements of your steel profile, as they may be able to order in what you need.

Do Post Frame Barndominiums Need 26 Gauge Steel?

Through Screwed Steel Roofing for Post Frame Barndominiums – What Gauge?

If I need to have major surgery, I am probably not going to ask for expert opinions on social media. However apparently, when it comes to construction expertise, Facebook is where to go. Always plenty of armchair engineers, semi-educated builders and competing structural systems to throw out their two bits worth.

American Iron and Steel Institute (AISI) has published accepted measurement standards for steel thickness. 29 gauge steel (post frame industry’s standard) has an average thickness of .0172 of an inch (with a minimum of .0142). 28 gauge steel has an average thickness of .0187 (minimum .0157) and 26 gauge is .0217 (minimum .0187).

These thicknesses are all measured prior to application of any primers or paint.

Steel coil is sold by steel mills or wholesalers to roll formers by weight. Roll formers sell finished formed roofing and siding by lineal foot. Roll formers make the greatest profits by ordering steel coil as close to minimum thickness as possible, as it produces more lineal footage per pound. When roll formers order steel coil, they place orders by minimum steel thickness (e.g. .0145 min would be 29 gauge).

To give a perspective on steel thickness differences, from 29 gauge to 26 gauge difference in thickness is .0045 of an inch. A sheet of 20# paper measures .0038 of an inch. Roughly speaking, the thickness differences between these two gauges is about a sheet of notebook paper! In comparing minimum thicknesses, although a sheet of paper may not sound like much, 26 gauge steel is 31.7% thicker than 29 gauge, based upon minimum thicknesses.

Now more importantly – how much load will a steel panel carry? A post frame building’s “weak link” is not load carrying capacities of its steel roofing and siding, it will be found somewhere in its underlying framing system. Taking a look at span tables provided to us by Union Corrugating Company for their MasterRib® (MasterRib is a registered trademark of Union Corrugating Company) panel, when spanning 24 inches, 29 gauge will support a live load of 112 pounds per square foot (psf) and 26 gauge 150 psf. These differences equating basically straight line with thickness differences.

Unless a building is at a snow ski resort, roof snow loads are probably not going to approach 112 psf, but what about wind loads? The same 29 gauge MasterRib® panel will support 118 psf in wind load, roughly equal to 214 miles per hour! For a perspective, highest officially recorded wind speed measured in the United States was 231 mph. It was logged on 12 April 1934, at New Hampshire’s Mount Washington Observatory at the summit.

But, what about hail? Please read https://www.hansenpolebuildings.com/2020/11/steel-roofing-hail-dents/ and https://www.hansenpolebuildings.com/2020/11/how-to-minimize-possible-hail-damage/.

But, but – oil canning?

Oil canning is a visible, wavy distortion affecting cold-rolled metal products. It’s seen in flat areas of metal panels, and can be characterized as a moderate aesthetic issue. Typically, rippling, waviness, or buckling is especially seen in the broad area of a metal roof or wall.  Most popular 36 inch net coverage, through screwed, steel panels are manufactured with high ribs every nine inches and two low profile ribs in between. These low profile ribs almost guarantee no eye-visible oil canning will occur.


Bottom line is… do you need 26 gauge steel?  No, you probably really don’t.  29 gauge is going to do everything you need it to do.  When would you need 26 gauge steel?  If you are going to purchase an all steel building and have 5 feet between your purlins and 7 feet between your girts.  On a wood framed building with half those spacings or less, it’s almost always just overkill.  Beware of those who try to sell you something you don’t really need.

All Steel Buildings Propaganda Part III

NOTE: Today’s blog is part III of a 3 part series – back up two days for the beginning! For those who wish to skip parts I and II, a simple typographical error on the Internet got me to “hansonsteel.com” (Hanson versus Hansen-which is the company I work for) where I found an interesting page on “Steel vs. Pole Buildings”.

For sake of ease of reading, words in italics are those from the all steel building website.

Maintenance

Once your Hanson Steel Building is constructed, it is constructed for a lifetime; the buildings are virtually maintenance free for years.

Pole barns/buildings must have sheeting reattached on a regular basis. And wooden frames for doors and windows will need replacing. Sagging trusses or warped wood framing will cause steel to pull away from the screw connections thus generating water leaks. The leaks in-turn damage the wood construction further. Most pole barns/buildings will need a complete overhaul of sheeting, bolts and screws.

Pole Barn NailIn my thirty plus years, pole building sheeting has never had to be reattached. If proper screws (like those designed for diaphragm design) are used, the manufacturer guarantees the screws will outlast the steel roofing and siding. Companies using nails to attach steel to wood framing – yes, they will come out of the wood creating water leaks and damaging the wood framing. Using screws and the “right” screws as mentioned, stay tight over time due to their design, with the neoprene washer, do not allow water to enter.

I’ve been in all steel buildings which leak.  All steel buildings are often used for commercial & retail uses.  My wife and I frequent a ShopKo in Sisseton, SD. It had numerous leaks in the roof within 5 years of its construction.  The most frequent causes of leaks…in either all steel or wood framed buildings are: use of improper screws, inadequately installed screws, or screws missing the framework.   This retail building had customers walking around plastic covering damaged floor stock due to a leaking roof.  I saw huge dollar signs in looking at the ShopKo building for repairs, not to mention damaged valuable merchandise.  As a customer, it made me a bit leery to even be IN the building, wondering if the roof was going to come down as I watched it dripping into the many “catch” buckets.

The use of vinyl windows and steel jambed commercial steel entry doors eliminates the need for replacement. Prefabricated metal connector plated wood trusses will not sag, and once dried wood framing has been properly installed and fastened in place, warping is not going to occur. Again, I would like to see documentation of ANY pole barn needing a complete overhaul of sheeting, bolts and screws.

Roof and Wall Panels

All Hansen Steel Buildings offer 26-gauge roof and wall panels with strength of 80,000 psi.

Pole buildings are normally produced with a thinner roof and wall panel consisting of 29-gauge steel.

To give a perspective on steel thickness differences, from 29 gauge to 26 gauge the difference in thickness is .0045 of an inch. A sheet of 20# paper measures .0038 of an inch. Roughly speaking the difference between the two gauges is about the thickness of a piece of paper!

Now the important part – how much load will a steel panel carry? The “weak link” in a pole building structure is not the steel roofing and siding, it will be found somewhere in the underlying framing system. Taking a look at the span tables provided to us by American Building Components (ABC) for their Imperial Rib® (Imperial Rib is a registered trademark of ABC) panel, when placed across three equal spans of 24 inches, 29 gauge will support a live load of 124 pounds per square foot (psf) and 26 gauge 141 psf. The difference is only 13.7%!

Bottom line is… do you need 26 gauge steel?  No, you really don’t.  29 gauge is going to do everything you need it to do.  When would you need 26 gauge steel?  If you are going to purchase an all steel building and have 5 feet between your purlins and 7 feet between your girts.  On a wood framed building with half those spacings or less, it’s just overkill.  Beware of those who try to sell you something you don’t really need.

Read more about steel thickness here: https://www.hansenpolebuildings.com/blog/2012/01/steel-thickness/

Fire Rating

Pre-engineered steel buildings offer a Class C fire rating which is the same as masonry buildings. Hanson Steel Buildings are designed for heavy wind, snow, rain or earthquake commercial building codes and provide protection for the building contents.

Wooden pole buildings offer a Class A fire rating which is the lowest resistance to fire hazard. Wooden pole construction cannot be used in many areas where there are stringent building codes for wind, snow, rain, or earthquake.

According to Stephen L. Quarles, Senior Scientist, Insurance Institute for Business & Home Safety, Richburg, SC, “A combustible material will be rated as Class A, Class B, or Class C based on its performance in this test. A material rated as Class A would have a lower flame spread, and therefore a better performance rating, than a Class C material.”

Pole buildings are Code conforming structures and can be designed to meet heavy wind, snow, rain and earthquake design loads. We’ve had clients get permits and successfully construct pole buildings at high snow ski-resorts, in California, Miami/Dade (most extreme wind), New York, Alaska and Hawaii.  In fact, we have pole buildings in all 50 states, including very urban areas. As long as buildings are built to Code, there is no reason anyone should not be able to use post frame construction for their new building.

Let’s Talk Steel Thickness

Three decades ago, when I was a newbie in the pole building industry, I was working in the Willamette Valley of Oregon. One of the local roll formers was selling steel roofing and siding as 26 gauge or (as they called it) .018E.

To begin with, what is a steel roll former? The process of roll forming is one of the simpler manufacturing processes. It begins with a large coil of sheet steel which is fed through an entry guide to properly align the material as it passes through the rolls of the mill.  Each set of rolls forms a bend until the material reaches its desired shape. Roll sets (or dies) are mounted one over the other on a pair of horizontal parallel shafts supported by a stand.

As I am the curious sort, I inquired of this manufacturer, “Exactly what is .018E?” Their explanation was their steel panels would measure as thick as .018 of an inch including the paint! I also found, they were basing their “26 gauge” off the Browne and Sharpe Gauge Chart, which is for wire gauge, not sheet steel. Obviously truth in advertising may have been stretched.

The American Iron and Steel Institute (AISI) publishes the accepted measurement standards for steel thickness. 29 gauge steel (the standard in the post frame industry) has an average thickness of .0172 of an inch (with a minimum of .0142). 28 gauge steel has an average thickness of .0187 (minimum .0157) and 26 gauge is .0217 (minimum .0187).

These thicknesses are all measured prior to the application of any primers or paint.

Steel coil is sold by the steel mills or wholesalers to roll formers by weight. Roll formers sell the finished formed roofing and siding by the lineal foot. Roll formers make the greatest profit by ordering steel coil which is as close to the minimum thickness as possible. When roll formers order steel coil, they place orders by minimum steel thickness (e.g. .0145 min would be 29 gauge).

We found some challenges with this when we had a closely monitored government project which specified 26 gauge steel. We deal with every major roll forming company in the country, and not a single one of them could guarantee their 26 gauge steel as being able to meet a minimum steel thickness of .0187. All of them confessed to ordering 26 gauge as either .018 or .0185 min!

To give a perspective on steel thickness differences, from 29 gauge to 26 gauge the difference in thickness is .0045 of an inch. A sheet of 20# paper measures .0038 of an inch. Roughly speaking the difference between the two gauges is about the thickness of a piece of paper! In comparing minimum thicknesses, although a sheet of paper may not sound like much, 26 gauge steel is 31.7% thicker than 29 gauge.

Now the important part – how much load will a steel panel carry? The “weak link” in a pole building structure is not the steel roofing and siding, it will be found somewhere in the underlying framing system. Taking a look at the span tables provided to us by American Building Components (ABC) for their Imperial Rib® (Imperial Rib is a registered trademark of ABC) panel, when placed across three equal spans of 24 inches, 29 gauge will support a live load of 124 pounds per square foot (psf) and 26 gauge 141 psf. The difference is only 13.7%!

Unless a building is at a snow ski resort, roof snow loads are probably not going to approach 124 psf, but what about wind loads? The same 29 gauge Imperial Rib® panel will support 163 psf in wind load, roughly equal to 252 miles per hour! For a perspective, the highest officially recorded wind speed on Earth was 231 mph. It was logged on 12 April 1934, at New Hampshire’s Mount Washington Observatory at the summit.

Bottom line is… do you need 26 gauge steel?  No, you really don’t.  29 gauge is going to do everything you need it to do.  When would you need 26 gauge steel?  If you are going to purchase an all steel building and have 5 feet between your purlins and 7 feet between your girts.  On a wood framed building with half those spacings or less, it’s just overkill.  Beware of those who try to sell you something you don’t really need.