How a Truss Designer Becomes More Efficient
When it comes to truss design, speed and accuracy are extremely important attributes to a designer. Other important facets include the ability to interpret plans properly and the ability to communicate with others in a concise manner.
The world of truss design requires more than just dedication. One must immerse themselves in every aspect from plan reading and a working knowledge of appropriate software programs to building, shipping, and assembly of the finished product. One needs the tools of experience, an adequate computer and the most important thing…an open mind!
Have a Plan
To begin with, the most essential trait of a good truss designer is a healthy understanding of how to read an architectural plan. The blueprints of a structure contain the instructions on how the structure will be put together. The truss designer is not the only person who will be working with the plans. Everyone involved in building the structure will refer to the plans, which is why it is imperative that the truss designer be fluent in each plan that comes across his or her desk.
Though it may be an easy enough concept to grasp, the technicalities of an architectural plan require the ability to decipher what one person has intended without talking to that specific person for the most part. Plans contain a number of different details, such as:
- Wall widths and heights
- Roof pitch
- Overhang length
- Ceiling conditions/transitions
- Specific loading requirements
- Mechanical requirements
- Finish work
- A bunch of other odds and ends
Some of the details that need to be interpreted are small and have the potential to be overlooked. A component designer take their time while reading a plan and make sure to digest all of the details pertaining to the job that will be necessary for the creation of an accurate truss and panel layout.
In truss design, inches equal feet. For instance, if there is brick cladding on the plan that isn’t properly accounted for on a layout the resulting trusses will be approximately five inches off (on each end). Five inches doesn’t sound like a big deal, but if there is a five-inch discrepancy in what the span of a truss should be and what the span actually is, there will be significant issues with putting the structure together on site.
After all, how do you build a project like this without a plan, right?
Use the Tools
The next big hurdle to overcome is a working knowledge of the software program. There was a point in time, prior to 1970, when software wasn’t a part of truss design and the designer ran all of the calculations and drew the trusses by hand. Creation of truss design software was meant to alleviate the anguish of manual calculations and cut down on time spent drawing individual trusses.
Software programs also aid in building trusses. One advantage of manual truss design was that all one needed to do was put pencil to paper. Now, designers must learn the inner workings of a software program. Learning a software program is time-consuming and can be frustrating. However, knowing what makes the program “tick” allows the designer the ability to speed through creating a layout and designing trusses. There is no need to erase anything and in just a few easy steps one or two trusses can be changed to top chord bearing if necessary.
For instance, in MiTek, to create a special heel condition, the top chord bearing command must be entered, then “truss basics” needs to be pulled up, and under the “heels” tab “do not solve heels” drop down must be selected. Fast, easy, and simplistic. There is no need for calculations and lumber charts, because the software runs the necessary calculations and indicates whether the truss fails or passes. The only jump that needs to be made is learning what commands are necessary to get the goal of the designer from his or her mind to the truss itself. Once the truss designer has become comfortable with the software, efficiency and accuracy are greatly increased.
Define the Roles
A great truss designer does his or her best to compensate for everyone else’s role in the building of a specific structure. When the truss itself is built, lumber is cut, jig sets are composed, and plates and nails are affixed. Truss manufacturing facilities may have state of the art machinery, which decreases some of the labor required to manufacture the truss.
However, not all plants are state of the art. Some plants have only a tin roof over the table where jig sets are configured. For the people who build the trusses under lesser conditions, the work is back-breaking. These builders are out in the elements; staggering heat in the summer, blistering cold in the winter. Rain or shine these people are kicking trusses out for each job that the company gets.
In regards to the builders, the truss designer makes sure that there are as many like trusses on a layout as possible. Webbing is taken into consideration. When a multiple step ceiling condition exists in the same run of trusses on a plan, the designer has the option to use “filler” webs to complete the step so that the truss can be configured using the same jig set for the most part. Splicing is monitored. In a run of trusses, the lengths of lumber used on the bottom and top chords are made the same. Continuity in webbing and splicing makes the job for both the builder and the cutter easier.
Shipping is also important to a designer. An escort is required if the truss height breaches the maximum height for transport. Some companies allow escorts and some regions over-span trusses will not fit on the roadway, requiring the designer to use piggybacks. However, piggybacks can get expensive. So, for companies that do allow escorts, the designer considers whether it would be more economical to create piggybacks or request an escort. Either way, the shipping is accounted for in the design of the layout and truss engineering.
Know the Reality
Lastly, the truss designer must make sure that the truss won’t break while it is lifted onto the building, so noting the span is very important. Girders must be loaded to support the trusses that bucket into them. Hangers need to be specified by the designer and the name and quantity of the hanger(s) is noted on the layout. Trusses must also be loaded appropriately to support various construction workers that will be working within and on top of the trusses while the structure is built.
The designer must know how the truss will be:
- Hoisted up on top of walls
- Connected to one another
- Loaded support workers & roofing material
- Locations for duct work & insulation
- How sheathing & drywall attach
As for the duct work, and HVAC units, the truss must accommodate not only the weight, but also there must be space in the webbing for installation. Proper roofing and ceiling materials are applied as well. All of the different roofing and ceiling materials as well as the ducts and HVAC units are compensated for by the truss designer.
There are many concepts and details that require attention on a layout and it is extremely important that the plans be interpreted correctly. The blueprints are used and referenced numerous times throughout the construction of a building. Before the creation of design software, everything was done manually. Drawing a truss layout, engineering trusses, and compiling a cut list was far more difficult and time-consuming. Now with a few clicks, a designer can efficiently input a layout and properly engineer trusses. Though navigating a software system can be a cumbersome prospect, with practice and dedication one can fly through a truss job.
A truss designer must consider many other people and aspects of a job. Knowledge of building, shipping, and installment of trusses makes possible the compensation for those that will be involved in the aforementioned steps. It is important to make the job of the truss builder as easy as possible as this plays into the efficiency of a finished product. Understanding of shipping criteria allows for the most financially frugal design. An in-depth comprehension of how the trusses are erected makes it possible for the designer to aid in seamless installation. All in all, truss design is an art with many different concepts and aspects to consider. Truss design is not for everyone, but those that are willing to step up have truly earned their place in the world of construction.
All of these things lead to one thing: Education. If a truss designer has not had proper training, there will be costly discrepancies that lead to loss and inaccurate product. We recommend that each and every designer dedicate at least 10% of their week to continued growth. A truss designer needs to have time built into his/her schedule to stay up to par with training for the following 10 key areas:
- Software changes/upgrades
- Code changes
- Builder preferences
- Field visits to understand the product application
- Manufacturing facility changes in equipment and procedure
- Peer mentoring to improve efficiency
- Quality assurance improvement
- Optimization as it applies to new features/equipment/inventory
- Shadowing others to learn advanced techniques
- Documenting knowledge in your head to share with a mentee
An overall scope of truss design has been briefly addressed in the previous paragraphs to grant insight regarding how comprehensive the job is. Admittedly, we have only scratched the surface. I could add another 1500 words, but I don’t want to put you to sleep! Please add your comments below and continue the conversation.
Ashley Casey – Design Professional
Gould Design, Inc.