Structural column defects:
This article explains how to notice defective, damaged, improperly supported, or missing structural columns, and other structural column & pier mistakes. Our page top photo shows a telepost used as a "permanent" supporting column. Most models of teleposts or "jackposts" are thin-walled steel and are not designed for permanent use. And all columns require proper bearing support at both the column top and bottom. This leaning, cockeyed jackpost is a structural collapse waiting to happen.
Detecting omissions, such as leaving out a column or it's pier or footing is an important step in learning how to recognize and diagnose various types of foundation failure or damage, such as foundation cracks, masonry foundation crack patterns, and moving, leaning, bulging, or bowing building foundation walls.
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This article describes a structural column defects in residential buildings. Larger structures using supporting columns and piers certainly require additional professional design from a civil or structural engineer or similar design professional.
Watch out: Some of these residential column or post defects are dangerous and risk collapse. But do not fail to pay careful attention to the structural connections themselves: connections between posts and beams, posts and piers, beams and the floors or ceilings they support.
Connection failure is often the weak link in residential structural movement and collapse.
See DECK COLLAPSE Case Study for an example. FYI we call a 6-inch concrete filled steel column a Lally column after its inventor.
Some folks call these just steel columns, or lolly columns or steel posts.
Our photos below show a proper use of a temporary column, telepost, or jackpost - that gray screw-jack to the right of the white-painted steel column I am touching. The second photo at right shows why the temporary column was put in place: the hollow steel column supporting this beam had rusted through at its base, risking collapse.
Watch out: The collapse of a structural steel column is increased if the column is hollow, rather than concrete-filled.
However what you see in the photographs above is a temporary repair. The rusted steel column should be replaced with a structural column such as a concrete filled steel Lally column that is rated for permanent use.
Our next structural column photo (left) shows a thin-walled adjustable column in use in a wet crawl area. The repair contractor installed gravel and then plastic to keep moisture levels down in the crawl space. (The post is probably not out of plumb, that was a tilt in the camera when I shot this photo.)
But notice that the column extends down through the gravel into the presumably wet surface beneath.
Consider that the end of the column is now hidden from view in gravel, that we think this is a recurrent wet area, we can't see if it's wet or not, and more, because this is a tight crawl space, people won't enter it very often to inspect conditions there.
A more durable repair would have been a Lally column. Some builders even prefer to use a pressure treated wood 4x4 post in this sort of location, arguing that it is "rustproof".
Shown below, some adjustable screw jacks or teleposts such as some Read-I-Post columns are constructed of a heavier-gauge steel and in some jurisdictions they may be approved for permanent use in structures. Often where an adjustable column is permitted for permanent structural use, once it has been properly adjusted in height, its adjusting rod is removed and the screw is tack-welded in place.
Notice that the installer took care to bolt the Red-I-Post top plate to the beam underside. Let's hope that the beam itself is secured to the floor joists overhead and is protected against lateral movement.
See our page top photo for an example of a horrible installation of a jackpost that is likely to collapse. Below are more examples of improper telepost installations. At below left we have inadequate bearing surface and no connection between the steel bearing plate and the joist underside. It looks as if the post may also be out of plumb. Boing!
Our second dangerous telepost photo at above right you can see that the post top screw has bent the steel plate as it pushed into the beam, and the whole assembly is slipping off of the beam and moving to the right. Some installers place screw jacks or teleposts with the screw down against the concrete floor or pier top.
That allows the larger-diameter post "bottom" to be placed up against a steel plate and against the underside of the beam. This "upside down" installation reduces the chances of bending the steel supporting plate and it also places the thick steel screw down on the (often wet) basement or crawl space floor. The thicker steel screw is slower to rust through to the point of collapse than is the thin-walled hollow steel pipe that forms the body of most teleposts.
It seems obvious that in addition to spacing requirements for supporting steel columns below beams (typically a steel column is placed every eight feet on center in a wood frame two story residential structure), you would also place the column below any splices in the beam.
But a splice in a structural beam also needs resistance to bending upwards. Look closely (click any of our images to see a larger view) and you'll see some nice wood putty in that opening splice joint.
The splice shown in our photo of a home in Portland ME would probably not have bent if it had been located below that floor joist to the right, and had the supporting column placed below the splice as well as below the joists.
As we also discuss at EARTHQUAKE DAMAGED FOUNDATIONS, defective supporting columns failed at Northridge Meadows during that 1994 earthquake. It appears that hollow 6" pipes were substituted for concrete filled steel Lally columns under part of the building. Once the fireproofing wrap was installed it was not possible to spot this shortcut by visual inspection.
The hollow columns failed, permitting the upper floors of the structure to collapse. There were fatalities.
Here are examples of types of omission that contributed to a structural collapse. During our work at the Northridge Earthquake site in California in 1994 we noticed that some of the supporting Lally columns were hollow rather than concrete filled.
Perhaps due to material shortages or rush during construction, these hollow, and weaker supporting columns were wrapped with a fire-barrier just as were the "real" supporting columns used elsewhere.
Our photos show a section of Northridge Meadows which collapsed during the earthquake. In the second Northridge Meadows building collapse photograph just above you can see that this column was hollow.
Our opinion was that these were defective columns and that they were a factor in the structural collapse during the Northridge earthquake. Other areas of the same complex moved, columns even leaned, but they did not collapse where the columns were of the proper type and were properly connected to the structure.
Other factors in the collapse appeared to include how exterior sheathing had been nailed across or not across certain sections of the building supporting walls. Our list of examples of defects of omission during foundation construction continues below.
See EARTHQUAKE DAMAGED FOUNDATIONS for more about the defective supporting columns that failed at Northridge Meadows during that 1994 earthquake.
"Missing" column footings may or may not be a defect depending on design and soil conditions. In some jurisdictions, a poured concrete floor slab may be considered of sufficient thickness and strength to support the column.
Completely missing structural columns such as a basement Lally column, where an owner has removed the column to open up a basement space being remodeled for use as living area.
Our photo (left), illustrates one way you can spot a missing column: a Lally column top plate remains tacked in place on the under-side of a built-up beam in a basement.
Sometimes you can spot the imprint of this Lally column top plate as a rectangular impression on the underside of a beam even though the steel plate itself was removed. See our photo (left) where you can spot the rectangular imprint of a typical steel Lally column top plate and even two nail holes where the plate had been tacked to the beam underside.
Contextual Clues May Indicate a Missing Structural Column or Post.
A second clue that a supporting column could be missing is contextual: in a conventionally-framed contemporary one family wood structure with a finished basement, especially if the main center girder is a built-up wooden beam, notice that the basement has been converted to a large, open rec-room.
And notice that there is a long span, perhaps sixteen feet, with no supporting post. Perhaps the center girder has been boxed in or covered with paneling and corner molding.
Ask yourself: when this house was built, given that typically I see a Lally column every 8-feet, I wonder if there was one in the center of this room. Was it removed? Was the center girder reinforced with steel? Is there sagging in the floor above?
Our photo (above left) shows a basement girder supported by cute little 2-inch pipes.
We think the installer knew these were not structural-components, because s/he installed these toy "faux-structural" pipes on 5-foot centers.
Failure to compact the soil under a column pier or footing or under a poured concrete slab which has been placed on backfill can result in column settlement.
Our client is pointing to a supporting column in a location where we suspect that crack pattern around the column, combined with a slight but observable depression at the column base area suggests its pier may be settling.
When we see a column whose base penetrates the concrete floor slab we know the floor was poured around the column - the column was put in place first. We can't see if a proper pier was installed to support the column base - as is usually the case. Perhaps in the installation we show here, the builder set a 4-inch solid concrete block on (poorly-compacted) fill inside the building foundation, set his post on that, and jacked away. When the fill settles the block settles too, and the column may move downwards, cracking the concrete floor around its base in the pattern we show here.
As we also discussed at BASEMENT LEAKS, INSPECT FOR, even a concrete filled steel Lally column can deteriorate enough to lead to building movement or instability. But hollow steel columns such as teleposts and even steel pipes people sometimes think will support a building, heavy exfoliating rust on the columns can lead to crushing or splitting and a structural collapse.
When evaluating the history of water entry in a building we like to look at structural components that have been in place since the building was completed - those are parts that will have been exposed to flooding or recurrent wet floors if water entry has been a problem.
Light superficial rust on a Lally column base is not structurally significant, though it might indicate a history of wet floors in the area. The rust shown at the Lally column base at below left is just a chip, it is insignificant, and we concluded that there was no evidence of a history of wet floors in this basement area. The steel column at below right penetrates the floor slab - we think it may sit on a hidden pier (there was no sign of settling).
But the column surface rust at below right suggests the floor has been wet in this area. We did not think this column had suffered damage that risks it's structural integrity. Click THIS LINK To see another photo of rust on the base of a steel column in a basement that we verified over a 12 year life had been subjected to recurrent wet floors but never flooding.
More photos of superficial rust damage to a hollow residential structural steel post are at POST COLUMN RUST MINOR.
But when we see exfoliating rust, some careful poking around to see just how much damage has occurred can help us decide the urgency of replacing the column - and of course fixing the water entry problem . WATER ENTRY in BUILDINGS will help with the latter.
At below left we show serious exfoliating rust at the base of a steel column. It's reasonable to infer that this home has been subject to recurrent flooding to a depth of several inches.
Our second structural rust photo (above right) was very exciting. We were inspecting a house on Long Island when the owner mentioned that she had pumps running 24/7 in the basement to keep Long Island Sound at bay. There was a forest of steel supporting columns (some were just hollow pipes not real Lallys) in this home's basement - all were badly rusted.
As the owner, who was a big person, walked across the floor, the kitchen floor suddenly collapsed and fell down about a foot. We wondered if an earthquake had suddenly struck Long Island.
Trembling we both took another look in the basement. The Lally column shown above and supporting part of the kitchen floor had picked that moment to crush. It was rusted through from repeated flooding.
Also see FLOOD DAMAGE TO FOUNDATIONS.
2016/11/25 [Anonymous by private email to the editor]
Today, as we were cleaning out our garage, we noticed that one of the support columns for our 1965 split level home has a large rusty dent (about an inch tall) at the bottom. This support column, which we believe is original to the house, is holding up the second story bedrooms which extend over the garage.
We purchased the house about a year ago and do not know how long the dent has been present or what caused it. We have attached pictures taken from several angles.
Would you say this rusty, dented area is a problem that needs to be addressed or acceptable?
[Click to enlarge any image] Photo: a close-up of the bottom of the steel column described by the reader's question.
Thank you for the interesting support-post question . A competent onsite inspection by an expert usually finds additional clues that would permit a more accurate, complete, and authoritative answer than we can give by email alone. With that arm-waving done, I comment further:
From just your photos I infer that there has probably been a history of wet basement floor in at least the area of the post. Given that the home is 50+ years old, the total amount of rust on original post is not terrifying. I can't tell if what you're seeing includes evidence of any actual crushing of the post bottom.
If the post is crushing then it's an older type, no longer permitted, that is hollow. A modern Lally column used in this location would be filled with concrete - a detail that resists both bending and crushing. But many older homes used steel columns that were hollow. Just how much of a risk of structural damage hollow steel columns might suffer from rust depends on:
While I'm not a structural nor civil engineer, I expect that those professionals would all agree that light, superficial rust on a steel column is only cosmetic in effect, though it might warn that steps should be taken (get rid of water, paint the steel) in a residential structure like yours to protect the column from further rust. Thick flaking exfoliating rust on the other hand, seriously compromises structural steel.
At POST COLUMN RUST DAMAGE we show serious rust damage to a hollow steel column that crushed, resulting in the sudden collapse of a kitchen floor of a Long Island New York Home in an event that scared the hell out of the author.
I would pick up a hammer and first give rap or two on the post side at mid span. If it rings or sounds hollow, it may in fact be hollow, in which case IF there is crushing or bad rust you'll want to replace it. If the noise is more of a "thunk" the post is probably concrete-filled and crushing/bending of any significant amount is unlikely.
Below your photo shows this hollow steel column indoors in a finished garage.
Next, with a screwdriver, poke into the base of the post a bit. If you find it's soft rust and your screwdriver goes in to concrete, there's no urgent repair. If you find that the screwdriver pokes through rust into a hollow space up above the floor level then the column is hollow.
Finally: look for other signs of the extent of water entry and any related problems (moldy insulation, drywall, or rot or insect damage), and if needed, take steps to dry out the basement. A sickening amount of such guidance is at InspectApedia.com.
Thank you so much for your helpful response. We tapped on the post with a hammer today and it seems to be hollow (As are the other three posts located in our house. If in good shape, are these other hollow ones considered to be ok?). The metal of the dent was still intact, so we were unable to verify using the screwdriver approach.
The post is located in our garage and we believe the dent/crush area may be due to a horizontal impact of some kind. The rest of the post seems to be in decent shape with the exception of this roughly 1 inch tall by three inch wide dented area. Should our next step be to hire a structural engineer?
Also, please feel free to share the photos
With the caveat that nobody can afford enough insurance to promise a stranger that their house - completely unknown and un-seen except for a few photos sent by the correspondent - is "safe" or "structurally sound", still, looking at just your photos I can see no reason whatsoever to hire an expert for structural assessment.
If you saw signs of building movement, settlement, cracking, leaning, bending, bowing, heaving, then that would be a cause for further concern. A dent in the bottom of one hollow steel column with light, non-exfoliating rust on the column base, is not justification for requiring a structural engineering analysis of the building.
Take a look around your home for signs of movement or for superficial, recent cosmetic repairs that might cover such movement, or for floors, walls, ceilings that if not cracked or bent, bulging, leaning bowing, are nevertheless visibly out of plumb, square or level.
BY NO MEANS do I mean to sound glib, but in sum, there's not much justification for worry for just this column. The risk to you of being hurt falling down the stairs when going to the basement to look at this column is greater than the risk of the dented lightly-rusted column by itself. I mean, watch out for a "capture error" in which something you see so captures your attention that you fail to attend other higher-risk situations. Make sure your home has working smoke detectors/alarms, sound steps and railings, and that there are no obvious hazards in the electrical or heating systems.
If you had a home inspection prior to purchase of the home, you might ask the inspector if she/he saw signs of concern for damage to the structure as well as asking what repairs are needed to address Dan's 3 "D"s:
See FEAR-O-METER for an explanation of the importance of focusing your energy on things that are Dangerous, Don't work, or that are causing rapid, expensive Damage to the home.
see OTHER PEOPLE's MONEY for an explanation of why some consultants give you advice that is expensive for you, free for them, and that mostly is focused on reducing risk for the consultant rather than for you.
We appreciate your reassuring email and are certainly happier to think this is not a major problem.
In your previous email, does the word "crushing" refer to a vertical crush, like from a downward force? We had thought it included the horizontal impact (crush?) that may have caused the rusty notch at the bottom of our post. For the most part, our house seems as straight as an arrow. We don't see any evidence of other settlement beyond a very slight dip in the threshold of the master bedroom and some uneven wall tile in the bathroom (we think it's just really old, poor tile). Everything else seems very strong and straight. The inspector did not have any structural concerns. He did not see this area of the post in question due to lots of clutter, but from what he could see of the house, he raised no structural concerns.
One more question, if that's ok - in order to protect the column from further rust damage around the base, should we pick off the rust flakes and then paint over it? - 2016/11/28
Horizontal "crushing" of a steel post or column: good point. I agree that a post or column might be damaged by horizontal impact, and I add that a dent might be caused by both impact (even a hammer) OR in a case of heavy loading or overloading of a too-thin, under-sized column denting could be an early stage in "crushing". But those manifestations of column overloading in a residential property would be very very rare.
More likely somebody smashed a column near its top or base as a heavy-handed step in aligning the column to a plumb position.
If the column is hollow (a telephost, adjustable column, pipe, etc) denting is far more likley than if the column is filled with concrete (a Lally column).
When I refer to "crushing" I mean that a badly-rusted steel column actually crushed downwards from weight from above - shown in my photo just above, and discussed in more detail
at POST COLUMN RUST DAMAGE
To protect the steel column in your home from further damage:
Continue reading at PIER FOUNDATION PROBLEMS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Or see COLUMN & POST FAQs
Or see PORCH COLUMN REPAIR or REPLACEMENT for the repair of round or wood columns used on porches and in building interiors
For problems with settlement of piers below Lally columns see SETTLEMENT CRACKS in SLABS
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