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How do I know if a crack on a concrete building is serious or not?

One does not have to be a structural engineer to know that a crack anywhere on a building is not a good sign. Aside from being ugly, cracks can cause a lot of damage to a property that do not necessarily have to do with the structural stability of a structure. The truth of the matter is that cracks come in all shapes and sizes and depending on many factors, can hint at a serious issue or are merely unsightly and can be repaired rather easily.

Cracks that are not structural

Having performed thousands of inspections as a structural engineer, I can categorically state that the majority of the cracks I have seen are not serious to the point where a structural emergency repair is necessary. That is not to say that you can relax and ignore any crack. If you decide to ignore a crack on your house, you are risking that the crack is indeed serious and it could eventually lead to a safety risk.

There are many types of cracks that have strange-sounding names such as "crazing" and "shrinkage". I will try to keep this blog at a layman level and do muy best to explain some of the more common types of cracking that the common person is exposed to.

The most common type of cracking is what I would call a "surface crack" because it is of little structural consequence and it is basically what the name denotes. The origins of these cracks are varied but many times has to do with the manner in which the stucco is applied to the surface or the manner in which the plasterer mixed the stucco (maybe with too much water in the mix). If you look at most properties closely, you will see these types of cracks somewhere. These cracks are not serious in the sense that the structure will collapse. These cracks, however, are serious in the sense that they could allow water and moisture into the property and damage the interior or allow insect infestations. These cracks can be repaired by applying an exterior grade spackling you can buy at your local hardware store, or by merely painting the property and maintaining it throughout the year.

Crack that are structural

Concrete structures are designed by engineers to withstand outside forces. When a building is subjected to forces that the property was not designed to withstand, then cracks will inevitably appear. These outside forces include, but are not necessarily limited to, hurricanes, earthquakes, loads imposed by the occupants, snow, and settlement of the soils underneath, just to name a few.

Here in Florida it is common to see cracks at the corner of a house that are diagonal. An experienced engineer will be able to identify the type of crack and, depending on the severity, provide a solution to deal with the problem. Other cracks can appear next to a window or at the uppermost beams that are located adjacent to the roof structure. These types of cracks are easy to point out, but are more difficult to diagnose and provide solutions for.

Structural cracks are a serious matter since they can become worse over time and eventually render the structure unsafe. Engineers employ different investigative techniques and tools to diagnose different structural failures, but nothing compares to the experience the engineer has. While it is not in the scope of this blog to educate the reader about all the different types of cracking, their seriousness, and their consequences, it is important to note that hiring a structural engineer to look into it is of utmost importance.

If you suspect that there is a crack on your property, I strongly suggest that you seek out a local structural engineer to take a look at it. Depending on your area, an inspection and a report will cost you between $200 to $500. The report should contain the engineer's observations, his conclusions, and recommendations on what the next steps should be. If it is indeed a serious problem, the engineer should tell you right there and then.

Do you need to hire a suitable professional? Contact us (954) 434-2053. In G. Batista & Associates we have highly qualified engineers to carry out the work

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What is the difference between a Project Manager and an Owner’s Representative?

Throughout the many years in the construction and the engineering business, I have heard of many nomenclatures and meanings that often get confused and misused.  After all, the construction and engineering businesses are extremely complicated.  Products and materials may come and go and may be referred to by many different names; and after many years, get replaced by other products.  The many services and professionals that are used in the construction and engineering businesses are varied and at times also get confused. Such is the case of the Project Managers being called Owners Representatives and vice-versa.  This blog will explain the difference.

I will begin by defining what a Project Manager is.  A Project Manager is a person that manages any type of project. You have Project Managers that head a team of designers that are building a website, are researching a theory, or any other item that requires a team approach to accomplish. Of course, a project may also include the construction of a building or managing construction of any type.  It would not be a mistake to say “I am looking to hire a Project Manager to manage the installation of the drywall installation of my drywall company”.  It would also not be wrong to say “I am looking to hire a Project Manager to oversee the implementation of a quality control process for the manufacturing of a new electrical automobile”.  It will also not be incorrect to say “I want to hire a Project Manager to oversee the General Contractor for my construction remodeling project”.  So, as you can see, a Project Manager is basically a person who manages a team that is trying to accomplish something; whether it’s a construction project or not.

An Owners Representative, on the other hand, is a type of Project Manager that specifically deals with representing the owner of a construction project (i.e. the person that is paying for the construction). Since the Owner’s Representative represents the owner on a construction project, the specific scope of work and responsibilities that an Owners Representative may undertake may vary widely from job to job. As such, it is important that a good contract between the Owner and the Owners Representative be made where all of the duties of the Owners Representative are laid out in detail.  At times the Owners Representative may be in charge of making sure the safety of the project is overseen, and at other times it will not be.  At times, the duties of the Owners Representative may become so burdensome that the Owners Representative will be required to be present at the job site every day at all times if he is to fulfill the duties as laid out in his contract.

Simply put, an Owner Representative is a type of project manager.  It will not be wrong to use one or the other when you are referring to a person overseeing a job and representing the owner.  However, bear in mind that you are being more specific and that more people will understand exactly what you are referring to when you have an Owners Representative on your project and they are called out as such. It is sort of like saying “I’m going to the cardiologist today” as opposed to “I’m going to the doctor today”. Neither is wrong.  People will just understand the specifics of what the doctor’s scope of work is.

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What is the difference between an Architect and an Engineer?

In order to understand what the differences between an Architect and an Engineer are, we must first basically define these.

An Architect is a person who designs buildings and is typically the point person of a design team. 

An Engineer is a person that specializes in the design of a unique aspect of the building such as electrical systems, Air Conditioning systems, and plumbing designs. 

Architects and engineers must work together closely to design and construct the building. Although their duties overlap to an extent, they are totally separate professions with their unique skills and responsibilities. 

Architects and Engineers take a different curriculum in school. During college, architects will take more art-related classes, whereas engineers will take more science, technology and math classes. These different educational paths reflect the different focuses each professional brings to the project. While architects concentrate on the aesthetics of the project, engineers instead focus on the structural components of those projects. 

Generally speaking, the architect draws the plans showing general views and details of all the spaces and elements of the building, then the engineer based on those plans he draws another set of plans showing the specific size of all the structural components of the building. 

Therefore the key difference between an architect and an engineer is that the architect focuses more on the artistry, beauty, and design of the building, while the engineer focuses more on the technical and structural aspect of the building. 

If you as a customer need a little room, an addition to your existing house, renovate your existing residence, or to build the home of your dreams, then the very first thing that you need to do is, to hire an architect, because he is the qualified professional to translate your needs, and desires into habitable, functional, and beautiful spaces. Once the architectural design has been accomplished satisfying your needs then the architect will work together with the engineer to make sure all the structural components of the space or a building will perform their functions in perfect harmony. 

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Concrete Repairs on Parking Garage Structures

Sample of a Parking Garage

Introduction

Parking garages are very distinct structures form all the other structures out in the world. These structures have large beams and columns and thick slabs that are designed to withstand the daily weight of thousands of heavy vehicles. Furthermore, the vast majority of parking structures are open which means that they are in direct contact with the open air.  The weather and chlorides that are present in the air can lead to long-term effects on the concrete. Due to the aforementioned, owners of concrete parking structures should take special care in monitoring the state of their structure.  Naturally, timely corrective measures  significantly add to the longevity of structures.

Cracks on your concrete parking structure

Cracks on concrete appear due to many different reasons. These reasons range from pouring a bad batch of concrete, to improper curing during the construction process. In other words, its those cracks that are caused by the constant movement, expansion and contraction of the structure and the vehicle traffic.

If you are in a parking garage and you stand still while cars are passing by, you will likely feel yourself vibrating. Of course, this is normal and you shouldn’t be alarmed. The heat and cold cycles of day and night cause the structure to expand and contract.  All these items come together to cause fissures in the concrete on a long-term basis.  It is normal for a concrete parking structure to contain cracks.   Small cracks typically do not constitute a serious structural problem although a review by a structural engineer is always recommended.

In any event, any type of crack should be filled at a minimum.  Your structural engineer will be the person who determines which cracks are serious and which are not. Additionally, the engineer will be the professional that will not only quantify the amount of cracking, but will also provide you with the best method of repair.  Needless to say, engineers have the training and the experience to provide you with guidance on dealing with cracks.  Furthermore, it is beyond the scope of this blog to instruct the regular lay person on the ins and outs of  analyzing a structure.

Concrete spalls on your parking garage

As mentioned above, cracks can pose an immediate serious threat to the structural integrity of the parking structure.   However, cracks can also cause long-term damage to the parking structure in the form of spalling.  This spalling occurs when chlorides seep into the concrete and cause the reinforcing steel inside the concrete to rust, expand, and then rupture the concrete.  Click here for our blog on the definition of a spall. This is of particular note in a parking structure that is not only open to the elements, but also contains cracks where these chlorides can easily access the reinforcing steel and make it rust.

Damage to beams

Parking structures tend to have wide open spaces.  Engineers design parkings to have as few columns as possible so as to avoid any collisions with automobiles.  This means that the engineers must design long beams that span from column to column.  As you might have guessed, the longer the beam, the more stress it takes from the vehicles driving over it.  At times, these beams show outward signs of stress by sagging and cracking.  Concrete beams are critical structural elements in a parking garage.  If you see widespread cracking on a beam, do not hesitate to contact a local structural engineer to inspect it.  Depending on the size, location, and direction of the crack, it could be a tell-tale sign that there is a serious structural failure lurking.

Other types of repairs

If I were to provide a comprehensive list of all the issues that can arise in a concrete parking structure, this blog would be many more pages long.   Cracking and spalling are by far the most common and prevalent issues in a concrete parking garage.  To further illustrate, there are several other types of repairs that are typical and these are as follow:

Water Intrusion

Although parking garages are open structures, we still like to walk to our car without getting wet while we are still inside the structure.  If cracks are large, they will let water seep down into the concrete slab and the water will eventually find its way downward by the force of gravity.  Water that goes through concrete picks up chemicals that can consequently damage the nice paint job on your car.  Furthermore, parking structures also have construction joints and caulk joints that can fail.  If these joints are not properly maintained, they can also fail and cause water to seep to the interior of the structure.

Rusting plates

steel embed
This is a steel embed

Some parking structures are what we call “pre-cast” where many concrete pieces are brought in and welded together in the field.  Each one of these concrete pieces has an “embed” which is a small steel plate where the different pieces make contact and where the welders make the connections to build the structure.  These embeds can rust and sometimes fail.  Needless to say, these failures can lead to catastrophic problems and even collapses.  Although collapses are rare, the owners of these structures should be vigilant and have a professional make periodic inspections on the embeds.

Conclusion

In conclusion, parking structures are very unique types of structures.  They are constantly exposed to the ravages of the weather.  Also, they are subjected to extraordinary stresses from the vehicles that day-in and day-out travel through it. Eventually, failures in the form of cracking and spalling will appear and it is up to the owner of the parking structure to ensure that a maintenance regimen is applied in order to identify these anomalies and cure them.  As mentioned above, a structural engineer is your best line of defense in providing guidance.

This guidance is on the form of an inspection to identify any cracking and spalling that has occurred.    In fact, this professional can also help you in providing you with plans, specifications, and a protocol to perform these repairs.  Engineers that specialize in concrete repair, such as G. Batista & Associates, can guide you through the entire process. This includes obtaining a suitable contractor to perform the repairs.

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What is Concrete Spalling?

Choosing the Engineer

Florida is a great place to live.  First, you have the beautiful beaches. Second, you have great weather throughout the year.   Third, you have great architecture that includes art-deco to modern styles.  However, these positive traits come with their fair share of problems.  The high concentration of “salt air” can seep into the  concrete over time.

This is a sample of concrete spallingEventually, the salt air damages the steel inside the concrete and causes it to rust.  Ultimately, this rust causes the concrete to spall.   There are some complex chemical reactions that take place  for a spall to occur, but we will try to keep it simple for those non-engineering types.  As an introduction, the picture shown here is an actual spall.  The classical spalled concrete will show the reinforcing steel (or “rebar“) once the concrete comes loose.

Passivation Layer

Lets start at the very beginning.  When the original builder installs the rebar inside the concrete, it is typically in a pristine condition.  That rebar has a protective layer that is called the “passivation layer”.  Coastal areas have high concentration of salts (chlorides) that penetrate the concrete through microscopic hole in the concrete.  Next, these salts come into contact with the steel and damages the protective “passivation layer” on the rebar.  When this protective layer is gone, the rusting process will begin and will continue over time.  At this point there is very little one can do to stop the rusting.

Concrete Spall defined

Now that there is an expanding piece of steel inside the concrete, it will only be a matter of time until the concrete breaks.  This rupture causes both small and large pieces of concrete to become dislodged.  Those detached pieces of concrete is the spall itself.  Needless to say, concrete spalls are potentially dangerous and even life-threatening.   On high-rise buildings they can damage properties below or even make contact with a person.  Spalling concrete should be repaired as soon as possible since it will spread and get worse.  Eventually, the rusting rebar will render the structure unsafe.

There have been many instances where structural collapses have occurred and people have been severely hurt as a result. Spalling concrete is a sign that your structure is under attack and this sign should not be ignored. Many people kick the can down the road and leave the repairs for a future date.  The old adage of “a stitch in time saves nine” is most certainly true.  A concrete repair that costs $1,000 today, will cost $10,000 a few years from now.

I like to think of spalling as a type of cancer.  In the same way that a cancer can grow until you die, the same is true of a spall.  The exception is that there is no “chemo-therapy” that will cure the spall.  The truth is that the only way to take care of the spall is to remove it using special techniques.  These methods that are employed by contractors to fix spalling concrete is varied and a little complex.  The ICRI (or International Concrete Repair Institute) has very specific guidelines on how concrete spalls are to be repaired.

Structural Engineering 101

Pantheon Dome
This is the pantheon dome

Concrete has been used for thousands of years in various forms. The Romans built magnificent concrete structures that survive to this day, such as the Pantheon, with its impressive concrete dome. The Pantheon (see picture), however does not have any reinforcing steel in it because of its design. The dome’s concrete was always compressed under its own weight. Concrete by itself, without any steel rebar inside of it, can withstand a tremendous amount of this compressive force. On the other hand, concrete cannot withstand a large amount of tensile force, which is the force that wants to pull it apart. Because domes are hardly built these days, the structures that we build today are subjected to both tensile and compressive forces.  Around the turn of the century engineers noticed that if you include reinforcing steel inside the concrete,  it could  withstand  a  tremendous  amount of  tensile  forces in  addition  to compressive forces. This meant that one could now design and build all sorts of structures without being hindered by concrete’s structural limitations. This is how the era of building modern concrete structures began.  As such, without including steel inside your concrete to support the structure, you would not have a soundly-built building.  The reinforcing steel (rebar) inside the concrete literally keeps your entire structure from crumbling to the ground.

Conclusion

To conclude, concrete spalls are a fact of life in Florida where there is a lot of “Salt air” in the atmosphere.  In reality, there is very little one can do to avoid any spalling to happen in a structure.  However, if one follows a typical building maintenance routine, the chances that spalling can be found and identified increases.  Buildings that are painted frequently and are maintained suffer the least from this malady.

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Is Your Curtain Wall Leaking?

This is a Glass Curtain wall system

What is a Glass Wall?

What is a Glass Wall? Glass walls (or Curtain Walls) is a system of glass panels that cover a building.  The featured image on this post is an example of a Curtain Wall system.  Curtain walls differ from regular windows in that they fit to the outside of the building instead of fitting inside a concrete opening.  These glass systems are designed to be strong and to keep the weather out.  Most significantly, they are designed to keep the people inside safe and comfortable. Many modern buildings have glass that are made of special materials that allow light in and at the same time keep the heat outside.  This way, energy savings are increased as costs are kept to a minimum.

Can Curtain Wall Leak?

Curtain walls have been around since the 1950’s. This means that there has been enough trial-and-error in order to develop this system to where it is today.  Glass systems these days are complicated mechanisms that are comprised of hundreds of different pieces.  These window systems now have built-in  waterproofing and water-diverting systems that keep these from leaking to the interior. However, these are man-made objects and it is a matter of time until there is a failure that will allow water to enter.  Therefore, the short answer to the question above is “yes”.

Main Reasons Why Curtain Walls Leak

In my experience, these are the main reasons why curtain walls can leak:

  • Curtain walls have sealants, plugs, and diverters that directs water along a vertical stem.  The stem then leads the water to the exterior of the system.  Sometimes these items break, loosen, or are installed incorrectly.  Consequently, leaks will occur.
  • Water can enter at the top of the glass and then find its way to a failed gasket.  Gaskets are the rubber parts of a glass system.  Rubber can crack and fail as time passes.
  • In addition to gaskets failing, these rubber parts can also dislodge.  In order for gaskets to work properly, they must be constantly compressed.  Parts of the system may loosen over time and cause for these gaskets to create a breach in the wall.
  • Finally, these glass wall systems are typically made many pieces of aluminum that are fastened together.  Many times these parts are glued or screwed together.  Leaks can occur when the spliced pieces are poorly sealed.

What Can You Do About a Leak?

It is often very difficult to find the source of a leak.  A water stain can appear on a ceiling tile on one area, but the water can actually be coming in from an entirely different area.  When water enters a break in the building “envelope“, it travels by gravity through the path of least resistance.  Many times, it takes a little investigative know-how to find the source of a leak.  Other times, it proves to be much more difficult especially when the suspect is a curtain wall system.  It is not the intent of this post to go over every leaking scenario, but to steer you in the right direction.  Many curtain wall experts may be available in your area for hire.  You should seek out an experienced professional to help you out with your issue.  You can: