A competent erector is key to the successful completion of any metal building or roof construction project. The thousands of buildings that perform satisfactorily attest to that fact.
However, a poorly trained or inexperienced erector—even with the best of intentions—can create a multitude of problems. Based on my analysis of hundreds of post-construction problems, the most common cause proved to be improper erection. This held true for everything from structural collapse to lack of watertightness.
Since the erector’s role is so critical to the success or failure of a project, it is vital to find and hire someone who is knowledgeable and experienced in the specific type of metal building or roof erection at hand. Most metal roof manufacturers offer more than one product. Some erectors may have the training and experience to erect one, but not all, of a manufacturer’s systems.
Following are useful guidelines for finding a capable erector with a qualified crew. If you have limited experience with metal building and roof systems, consider hiring a qualified metal building consultant to help you evaluate the installer. Some buildings are more complex than others, and a consultant can help verify that the installer’s experience is a match to your project’s level of complexity.
Look at past projects.
Require a list of projects completed by the erector, including recent (less than 3 years old) and older projects. Carefully verify that the level of craftsmanship exhibited on all of these projects is satisfactory. Ask if mistakes requiring rework occurred on a project, and note how the erector responds. Did he own up to it, learn from it, or try to blame it on someone else?
Check for certification and training.
Find out if the installer is certified by your particular building or roof component supplier, and determine when crewmembers last attended a training session. I have observed millions of square feet of metal roof that were erected improperly by crews who were trained and qualified in heavy steel construction but not qualified to erect low-rise metal buildings and metal roofs.
Ask about communication.
Ask the erectors you interview how they plan to communicate with their crews. Determine if the superintendent will have daily meetings to instruct each crewmember how to do his part of the job. Without this daily communication, there is a good possibility things will go wrong. I’ve observed instances where communication was so poor that different members of the same crew were erecting critical roof elements differently, some correctly and some not.
Watch out for low bids.
Be very cautious in accepting a bid that is much lower than the others. On the surface, a low bid may appear attractive, but it can often lead to poor performance. There may not be enough money in the contract for the erector to get the work done correctly, yet the erector can’t or is unwilling to pay for it himself. this situation, the contractor may “walk” or declare bankruptcy. Remember, the cheapest erector can easily turn into the most costly one.
Don’t hire an erector who is overextended or has a poor safety record.
Sometimes an erector’s inexperience or optimism leads to overextension of his resources or poor safety standards, resulting in poor supervision, inferior workmanship, and other problems. Evaluate the specific resources and personnel the erector has available to utilize on your project. Require the erector to submit a copy of his OSHA-approved safety program, and make certain he is current on all safety requirements. Also ask if he holds regular jobsite safety meetings.
Once you’re confident that you’ve selected a qualified erector, you can’t sit back and breathe easy. The following issues must be attended to before work begins:
Don’t let your erector subcontract the work to a less-qualified contractor.
Insert a clause into the contract requiring that the labor portion of the installation not be subcontracted to anyone without your knowledge and express written consent. After all of your pre-qualification efforts, you do not want to have a less-qualified contractor do the actual work.
Make sure the erector has established a suitable erection sequence and staging area.
Lax site preparation can result in the erector working in a mud hole, suffering inadequate access, waiting on other trades, and many other obstacles—all of which may lead to job delays or poor results.
Confirm that the erection drawings and instructions are correct and available on the job.
You or a qualified representative should review the on-the-job drawings and erection information to make sure they are complete and apply to the system being used. Review the installation details against the manufacturer’s suggested installation details and industry standards.
On some jobs, when I asked to see the job drawings and erection instructions, I was shown a copy of old drawings that did not include the latest changes and had not Before Erection Begins been approved. I’ve even been on jobs where the erector was using instructions for a panel made by a different manufacturer. Both of these have the potential for problems down the road.
Insist on the presence of a full-time superintendent.
The devil is in the details. Many erection problems are caused by small elements that are overlooked or ignored, or by a crewmember who doesn’t follow the correct erection procedures. The superintendent should study and understand the erection drawings and instructions and stay on the job to check all the work as it is being done. Also confirm that a certified installer for the specific product is present at all times while the project is being erected. Be sure he also has the authority and ability to direct the erection procedure and the time to ensure every crewmember is doing the work correctly.
Making the point before erection begins that you expect the crew chief to do more than just work as a crewmember, that you also expect him to direct and inspect the work being done by others, is often sufficient incentive for him to hold regular crew meetings to instruct those doing the work how to perform procedures properly. There is no reason for the same job being carried out by two different crewmembers to have different results.
Don’t permit the erector to make design changes.
An erector who believes he can modify the design of the product, especially a roof, without checking with the designer is asking for trouble. On jobs where I have found serious problems with improper erection, I’ve asked why it was erected that way and have been told, “I just didn’t think it was necessary to follow the design details.” Today’s metal buildings are complex systems and seemingly small elements such as sealant, flange braces, and bracing play critical roles that require thorough evaluation before they are changed.
Unless you have complete faith in the erector and he is bonded, you or someone who is knowledgeable about the process should inspect the work as it is being done to catch errors and problems early. It is much easier and less expensive to do the work correctly the first time.
Watch for these common trouble spots:
Use of proper tools and equipment
Use of improper seaming tools or seaming procedures is one of the main causes of serious roof leaks on standing seam roofs. To prevent such problems, have a qualified inspector examine the seams early on in the project to make certain they are correct. Don’t delay this inspection until the roof has been completed and you have a major problem.
Temporary bracing during erection.
One of the most frequent causes of structural failure during erection is inadequate temporary bracing. This can be due to a lack of knowledge about what is required to brace the steel adequately or a lack of understanding about who is responsible for furnishing and installing the temporary bracing.
The wind load on a series of unsheeted standing frames may be greater than the wind load on the sheeted building. Bracing is a tricky business and must not be undertaken lightly. Some engineers and others have taken the position that the building should meet requirements for wind load as stated in the prevailing building code at all times during construction. This takes the design of temporary bracing out of the practice of accepted “rules of thumb” and makes it a rigorous procedure.
Under industry practices, it is usually the erector who is responsible for bracing. However, if a building fails during construction and the erector has not followed accepted industry design procedures, both the erector and you may be in serious trouble.
Structural failure after erection can frequently be attributed to improper or inadequate purlin and frame bracing. This often occurs because the erector does not adhere to design bracing requirements or the bracing is considered “fill-in” work and is not done in a timely manner. Major roof problems can occur due to inadequate bracing. The roofing must not be started until all of the permanent bracing is correctly installed and complete throughout the entire building.
Appearance problems are often exacerbated by out-of-plane structurals, use of poor materials, and sloppy erection, such as mud and marks from the erector’s feet, failure to control mastic applications, and excessive screw-fastener application.
Most buildings are properly constructed. Those that cause trouble are the exception. If problems develop, make a genuine effort to correct them as soon as they come to light. Don¡¯t cover them up and let them fester. Paying attention to the suggested guidelines should go a long way toward ensuring quality erection and satisfied clients.