What should home inspectors looks for when we find adjustable steel columns? We recently shared a few photos of some adjustable steel columns on our Facebook page, and this kicked off a great discussion about these columns. It made me realize that there are a lot of rumors out there about what is and isn’t acceptable, so I’m putting together a summary of what we ought to be looking for as home inspectors. There was a fantastic article published on this topic for home inspectors in the ASHI Reporter back in February of by Arlene Puentes, and is now available on her website at https://octoberhome.com/articles/adjustcolumn/adjustcolumn.html. I won’t attempt to re-create that article; I’m just hitting the high points here.
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There are two flavors of adjustable steel columns, and they both have a screw and a plate on one end to fine-tune the exact length of the column. One type is a solid column with just a screw. The diagram below from Tiger brand shows an example of this:
Section R407.3 of the International Residential Code (IRC) says that steel columns “shall be not less than 3-inch-diameter”. To the best of my knowledge, all one-piece steel columns are at least 3″ in diameter. These are approved to use as permanent supports.
The other type is a two-piece column, also known as a telescopic column. These have two pieces of metal that are similar in diameter, but one is slightly smaller than the other. The diagram below, also from Tiger, shows an example of this:
These types of columns are less than 3″ in diameter, which means they’re not approved for permanent support. They should be considered temporary supports or possibly “additional” support. Besides not being code-approved for permanent support, manufacturers will tell you the same thing about their products. Tiger says “Telescoping jacks should be used as additional support, not the primary means of support.” These are handy to use as temporary supports when structural repairs at taking place.
As a home inspector, the question you should ask yourself is “Is this telescopic post necessary?”
When we find telescopic posts installed in places where permanent structural support is clearly needed, we recommend repair. The photo below shows a good example of this, as permanent support is clearly needed for this stairway.
On the other hand, we frequently find telescopic posts installed to provide additional support, and we evaluate these on a case-by-case basis. If a floor appears to be originally constructed and properly supported, yet someone added a telescopic post in a place where it doesn’t appear to be needed, what should we say? This is a judgment call. We always point out that these telescopic columns aren’t meant to be used as permanent support, but we don’t always make a big deal about it. The photo below shows a good example of this:
The floor framing all appears to be in good condition, so why was this added? If you removed that support, what would happen? Surely nothing. Perhaps the homeowner wanted to reduce some of the bounce in their floor. I don’t consider this to be a big deal… but you’ll get conflicting opinions on this. Some home inspectors and some municipal inspectors take a hard-line stance on two-piece columns. These home inspectors may call for professional repair, and these building officials may require complete removal or replacement with permanent posts.
Let’s look at another example:
This beam appears to have a proper wood column installed, however, the column also appears to have sunk approximately 1-1/2″, which may indicate a failed footing. The steel columns were likely added after the fact, and they don’t appear to have any footings, but there are big chunks of concrete to help distribute the load. Is this adequate? I don’t know. At this point, I’d punt to a structural engineer to have them put their blessing on this installation or recommend repairs.
I’ve gone through three examples; one where support was clearly needed, one where it surely wasn’t needed, and another where I didn’t know. As home inspectors, these are the various situations we face on a day-to-day basis, and the answers aren’t always black and white.
Should the adjustment screw be located at the top or bottom of the steel column? It depends. To know for sure, you need to read the ICC-ES report.
What’s an ICC-ES Report? According to the International Code Council, “An ICC-ES Report is a document that presents the findings, conclusions, and recommendations from a particular evaluation. ICC-ES Reports verify that new and innovative building products comply with code requirements. ICC-ES Reports provide information about what code requirements or acceptance criteria were used to evaluate a product, and how the product should be identified, installed and much more.”
Tapco brands Tiger and Akron say the adjusting screw must be installed at the base, and after installation, the screw must be encased in concrete to prevent movement. On the other hand, AFCO “Zip” columns allow the adjustment screw to be installed at the top or bottom of the post. If the threads are left exposed, they must be damaged to a length of 1-1/2″ with a cold chisel or screw driver to prevent adjustment after it has been installed.
In short, adjustment screws should either be encased in concrete or damaged to prevent tampering.
The top and bottom plates need to be secured in place. The photos below show examples of this. The column that’s fastened at the top surely could have used some washers, but whatever. We’re just happy to see lag screws.
It goes beyond the scope of a home inspection to determine the structural adequacy of any individual column, but we can definitely check to make sure that everything is plumb, level, and straight. The photo below gives a great example of an unhappy column with a bent top plate. That alone would be enough for me to recommend further inspection and repairs, but this was also a two-piece column and it wasn’t fastened at the top. And the beam was twisted.
It doesn’t get much more obvious than this, right?
Also, inspect the bases of any steel columns for signs of rust or deterioration. The column below had a severely rusted base, and it appeared to be installed directly on the basement floor, not over a footing.
If a column has more than just a small amount of surface that can be easily scraped off, it should be replaced. And while we’re picking on this one, note how much of the steel threads are exposed. The maximum allowable that I’ve found is 4″. This looks like it could be more than that.
Two-piece steel columns shouldn’t be used as permanent support, one-piece columns are fine. Some manufacturers allow the threads to be up or down, others say the threads should be down and encased in concrete. The top and bottom plates should be fastened in place, and everything should be plumb, level, and intact.
Are you looking for an alternative column type than in-situ concrete, or you just want to learn about all types that exist?
I get it, by looking at buildings or structures we don’t really see what material or geometry is used because they are in most cases covered by insulation and cladding.
But also the word column in civil engineering is not 100% clear.
Because there are different categories of columns. In statics, we talk about static systems of columns, while on construction sites columns are differentiated by the material and geometry.
Let’s break it down in this post. We’ll show all types of columns, from static systems to concrete columns, and show the advantages and disadvantages of each one of them.
Without further ado. Let’s talk COLUMNS.
Columns are vertical structural elements which resist vertical and/or perpendicular loads. They are characterized by acting in compression. However, tension and bending are also possible. The loads travel through the elements and get distributed further to the next column, slab or foundation. Columns mostly support other columns, beams and slabs.
Columns are primarily used in a building to transfer the vertical loads down to the foundation and then into the soil.
Most of us think of concrete as the material for columns.
So it’s no surprise it’s the first in the list!????
Let’s find out what other materials are used and what geometries are common for columns.
In most countries, in-situ concrete columns are the way to build columns.
Concrete is cheap and has great structural properties.
And in-situ concrete technology allowed us to build infrastructure projects and skyscrapers such as the 828 meters high Burj Khalifa.
In the picture above, you can see in-situ concrete columns. What’s special about the in-situ concrete columns is that they easily connect to neighbouring elements such as walls, because they are casted at the same time.
This makes the structure watertight.
As the concrete is extremely weak in tension, steel rebars (reinforcement) is additionally required. To connect 2 columns with each other, reinforcement from one column is extended to another.
You can see these rebars in the picture as well. ????????????
I/H Cross-section are the most used structural steel columns in the building industry. They have been around for a long time, so structural engineers, builders and authorities know how to build with them.
In the picture above, you can see that the steel columns support a wooden roof.
The steel columns are also exposed to the environment, which means that additional coating is required in order to protect the steel from corrosion.
Want to learn how to design steel columns?
Then check out this guide, where we walk you through step-by-step!
As construction schedules are getting tighter, precast concrete columns are a great way of speeding up the total construction time, if the material concrete is used.
Contact us to discuss your requirements of column cladding. Our experienced sales team can help you identify the options that best suit your needs.
Precast concrete columns are, as the name says, casted in a factory, then delivered to the construction site and lifted in place.
This type of column has especially been popular in the Scandinavian countries.
The trend that timber gains in popularity is partly also due to the “new” technology of glulam.
Glulam is short for glued laminated timber. So timber laminates are glued together.
This leads to stronger timber elements which can take more loads.
In the picture above, you can see that glulam timber columns are used in a high-rise building.
A couple of impressive timber high-rise buildings have already been built, such as the Mjøstårnet.
This is an 85,4 m tall timber building. Impressive! Isn’t it?
Want to learn how to design glulam columns?
Then check out this guide, where we walk you through step-by-step!
Structural timber columns were the main types of column that humans built with for centuries, before steel and concrete were discovered!
Due to fires that erased many cities on the world, structural timber got more and more avoided.
However, structural timber is coming back. Building with timber is very easy and sustainable. A small timber cabin or canopy can be built by 1 or 2 people.
OK, so let’s have a look at the pros and cons.
I basically grew up this the circular concrete column from the picture above.
It’s supporting the garage ceiling in my parent’s house.
In this case, a circular column was favourable because we wanted to park cars on each side of the column, but we didn’t have a lot of space to open the doors.
Circular concrete columns are not as common as rectangular, due to the reason that they are a bit more difficult to produce.
However, they are in many cases great aesthetic features, don’t you think?
So let’s have a look at the advantages and disadvantages. ⬇️⬇️⬇️
An alternative to concrete or steel columns is a mix of it! Composite Columns!????
In this type of column, a structural steel section is covered by concrete, as the picture above shows.
There are plenty of advantages of this type. Let’s check them out!
This type of column isn’t too common. However, it has advantages over the other column types.
Circular steel columns are a great choice when exposed to torsional forces.
What are torsional forces?
Torsion happens when loads are applied with an offset to its centreline.
Now, behind every column in a building there is a static system.
Because we somehow need to know how much load the column has to carry, how we build the connections between columns and how the loads travel to the next column.
So, let’s see what options we have.
Let’s start with the “easiest” and probably most common steel column – the simply supported column.
This static system is basically a simply supported beam turned 90°.
It’s characterised by a roller and pin support, which results in 3 reaction forces.
For structural engineers, simply supported beams are quite convenient to design, because they are statically determinate, and the forces can be calculated by hand.
Another statically determinate column is the cantilever column. As for the simply supported column, the internal forces (normal, shear force and moment) can be calculated by hand.
It’s characterised by a single support – a fixed one, which creates 3 reaction forces.
So let’s have a look at some of its properties.
Now, this static system adds some rigidity and robustness to the whole structure, as it is statically indeterminate.
The internal forces of this column type can’t be calculated by hand any more, and advanced software programs or formulas should be used.
Now, to add even more rigidity and robustness to our overall structure, 2 fixed supports can be chosen for the static system of the column.
Both supports then have 3 reaction forces each – Moment, vertical and horizontal force.
The internal forces of this column type can’t be calculated by hand any more, and advanced software programs or formulas should be used.
Now, that you got an understanding of what type of columns we use in structural engineering, you can learn about loads, because every column is exposed to loads.
Because there are always multiple loads acting on a column. Considering these different loads in the structural design is done by setting up Load Combinations with safety factors.????
Once all load cases and combinations are set up, the structural elements can be designed. We have already written a lot of guides on how to design columns. Check them out.
I hope that this article helped you understand the different types of columns and how to go further from here. In case you still have questions.
Let us know in the comments below ✍️.
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