Saturday, September 22, 2007

Steel Posts and Beams

The North Star Construction Square House is set apart from standard residential housing in many ways. Our mission has been to design and engineer a home that is not just different, but better. Our design requires as little material as possible, produces as little waste as possible, and ends up being a home requiring little or no maintenance due to the materials and design.

Steel post and beam construction is primarily reserved for extremely large industrial buildings or high end custom home construction. Our experience over decades of work in both of those fields has led us to the understanding that the reasons why steel post and beam construction is normally a costly method of building is not due to the material costs. It is due to the design of those structures and the amount of labor required to change the stock materials into custom shapes and sizes.
Therefore, in our Square Houses we utilize steel structural materials in the lengths which they are produced, decreasing or eliminating the need to work with (or rather against) those materials.
Most homes are designed with specific room sizes as a starting point. Our structures start with materials dimensions and we work backwards from there to produce a functional and comfortable floor plan while radically decreasing material waste in the process.
Steel I-Beams are produced in 40’ lengths. Our homes use 40’ I-Beams. No cutting, no labor, no waste. The materials are ordered, delivered, and hoisted into place. The steel posts which we use are produced in 20’ lengths. We have spent the time with pen, paper, and computer to eliminate the time required with saws, grinders, and torches. In our designs, a single 20’ steel post is cut one time in order to produce two usable posts. The central posts are each one half of a full 20’ section and the north and south posts are both taken from a full 20’ section as well. All of this is done without one single piece of wasted steel or one single man hour on site. All the materials come from the steel plant ready to be incorporated into our structures. No site cutting, so splice plates to be welded, no bolt plates to be drilled. Everything shows up ready to go, just as it is. Other elements of material savings arise from the use of steel as a post and beam material. In order to produce a largely passive solar home, we have maximized the amount of glass (primarily south facing glass) in our structures. By doing this, it requires large free spans and without moving towards steel as a component, an incredibly large amount of wood would be required to create those spans. And it is not just wood that would be required, but manufactured wood which means that the trees are not only cut down, but they are then processed into beam material. In looking at the entire package of sustainability, it is important to look at the processing methods for materials and how much energy goes into producing those materials in reference to what their likely life spans will be as a building material. You must look at not just what the planet must give up for that function, but also how long that material will last in that function.
The Square House supporting structure is comprised of 6 steel posts and 3 beams with a structural concrete and block fireplace. The walls and glass panels in between the posts are not load-bearing. They are integrated as shear-panels in order to aid in the resistance to lateral loads, but the walls are not incorporated to bear vertical loads. This gives us great flexibility with our design in regards to window location and size.
Our design starts with a fully engineered and reinforced concrete footing section and block pilasters. The stem wall blocks are reinforced with steel bars and are core filled with concrete after being insulated on the interior and exterior surfaces. Steel plates are welded to the posts
Steel anchor bolts are cast into the pilasters anchoring the posts and plates directly to the foundation
creating a structural bond from footing through the post structure. The posts are also incorporated into the concrete slab with reinforcing bar thereby producing a post and beam structure that is actually integrated into the foundation, stem wall, and slab of the house.

Anchor bolts are welded to the faces of the posts in order to bolt the wall panels in place, creating a membrane of resistance to lateral loads.
Anchor boltsare welded to the top surface of the I-Beams to tie the entire roof structure into the previously raised structure. The I-Beams are attached with full circumference welds to the posts locking the entire structure from truss to footing. While most structures you live in are held together with nails, Square Houses are bolted from roof truss to concrete footing and engineered to stay that way. The Square House design is not a better home because it is attractive. It is attractive because it is a better home.

For more information or to schedule a tour of one of our homes, please contact our sales and contract manager Ed Lyons at 1-505-577-0490 or by emailing him at If you have a specific technical or design question, you are welcome to contact our senior designer Paul Werenko at . Thank you for your time and interest in what we do.

Our next information section should be up soon so please check back!

End Note #1:
There is one other element to our steel post and beam design which we are so proud of that I feel compelled to include this information. As we have already discussed, the central posts are each one half of a full 20’ piece of steel. The north posts and the south posts come from another full 20’ section. Although our calculations for proper solar gain have been developed for the latitudes of central to northern New Mexico, our design allows us to adapt to any latitude. Since both the north and south posts come from one 20’ section, we can add to the dimension of the north post (before cutting) while decreasing the dimension of the south post by that same amount (or vice versa) in order to angle the roof plane for our projects that lie outside our latitude (without wasting one inch of material or changing the structural engineering!) The central posts stay the same length and the entire roof plane pivots to the south or to the north and can be adjusted in the design phase for sites that may exist from Central America to the Arctic Circle. (Yes, we can do the southern hemisphere too.)
End Note #2:
For our engineer friends, I refer to the I-Beams as I-Beams and not the technical term “W” in order to avoid the necessary ten paragraphs to describe the difference between the two. We know they are “W’s” and more specifically, the beams we use are W10X22 End Note #3:
Technically, they are CMU’s and not Cinder Blocks. The CMU stands for Concrete Masonry Unit, and although the industry used to call it a Cinder Block, we don’t any more. But the interesting part is that the name was changed because cinders are carcinogenic and they are no longer used in the manufacture of blocks. So, although you will hear people say “Cinder Blocks” the truth is they are no more cinder than a 2x4 (which, by the way, a good botanist will tell you that a 2x4 does actually contain trace amounts of cinders).
End Note #4:
A designer is not an architect. An architect is not an engineer. Contrary to popular belief, the home you are most likely living in right now was not engineered. It was, however, drawn by someone, most likely a designer or an architect, but that does not mean that it was engineered. Standard housing in the US does not require an engineer’s review or involvement. Most people are shocked by that simple fact but it is true. The common argument for engineering being “not necessary” in the process of residential home construction is that building codes, if adhered to, provide a level of protection against improperly built structures. Although this may protect against improperly built structures, it will not guard against improperly designed structures. Our homes are designed by us and engineered by Walla Engineering of Albuquerque, New Mexico. We would like to thank Mike Walla and his entire staff for decades of professionalism and not just answers, but the right answers.
End Note #4b:
State construction inspectors are, in the current building environment, overtaxed. Their work loads allow them brief visits to the jobsites at best. It is common that in a 5 month project we will actually have a total of 30 to 40 minutes of inspection time. A quality builder cannot anticipate that state sanctioned inspections are going to provide any semblance of engineering. That, coupled with our belief that when someone says they “build to code”, it simply means that they are building the worst structure that the Federal Government will allow them to build. Codes, like speed limits are thresholds that one should not hover around. Our structures are engineered to provide the best house without material waste. That is the code that should be adhered to, not the minimum standards allowed by your elected officials, who are, I might ad, not engineers (and most likely, neither is your inspector).