With plenty options for floor systems in the market, it’s important to get the facts and insights directly from the experts. In our latest Pros Know edition, discover the real-world advantages of engineered I-joists compared to open web floor trusses. 

Watch the video below or read the Q&A to help you make confident decisions for your next single family or multifamily project. 

Q&A Session – I-joists vs. Open Web Floor Trusses 

Greg Wells, Director of Marketing: Thanks for joining us again, Dan. I want to talk a little bit about open web trusses. There’s a lot of conversations out there, a lot of questions about what’s better with i-joist or open web – obviously, both of them have their place in the market, and they’re very good competitors with one another. But let’s kind of get into the nitty gritty on that. Can you talk about installation and running mechanicals in each of those solutions?  

Dan Cheney, Wood Products Director of Engineering: Oh, you bet, Greg. Initially with the open web truss design, it would make you think that it’s going to be easier to run mechanical, HVAC, plumbing, etc. But when you get into the layout phase, there are parts of the open web truss that cannot be cut. But with i-joist, and with some pre-planning, you can actually allow for straighter runs with fewer turns and less waste.  

GW: So, it’s easier, you have realistically more flexibility with an I-joist to put mechanicals where they’re needed?  

DC: That’s correct. Greg.  

GW: What about the strength and performance of the two solutions?  

DC: Floor trusses are only as good as the lumber that’s being used to manufacture them. Typically, solid-sawn lumber comes at higher moisture content that varies quite a bit more than engineered wood. When you compare that with i-joists—they are constructed with laminated veneer lumber flanges at a lower moisture content. And so, you get less shrinkage and warpage, especially when you compare it to a product like an open web floor truss that’s made of solid-sawn lumber.  

GW: When you talk about moisture content, what does that mean, really? If the lumber shrinks after it’s installed, what kind of issues could that potentially have?  

DC: Typically, the noise you hear when you walk over a floor—that squeaking sound that you get is the nail friction between it and the shrunk away piece of solid-sawn lumber. If that piece has less propensity to shrink, then you get less noise as you walk over a floor.  

GW: So better performance through the long haul with an i-joist? You have less variability, essentially?  

DC: That’s exactly right, Greg.  

GW: So that gives us a solid foundation on understanding of where we’re at. But what about installation between i-joists and open web floor trusses?  

DC: Yeah, so i-joists are field trimmable, lightweight, and don’t usually require a large crew to install the floor. Open web floor trusses are usually heavy and bulky and sometimes require a crane for installation, increasing your installation costs and time at the job site.  

GW: We keep hearing over and over one of the main issues in the building industry is labor. So if you have an opportunity to save some labor costs, that’s a huge advantage right there. 

Changing gears now, out in the marketplace, we’ve seen some price comparisons that don’t necessarily match up. Can you talk about that? For example, when hanger is needed, when rim board is needed?  

DC: As you know, the design of each project is individual. So, as you compare different framing materials, you need to make sure that you’re comparing apples and apples. As an example, is it a free, open span where the products are spanning from wall to wall? Or do you have a beam in the middle where the products frame into? So, as you’re evaluating each floor plan, you want to look at the different sizes that we have available to maximize the span, minimize the cost, and reduce the waste on each job. 

GW: Perfect. And I know we have some software out there that will allow a customer to pick the floor performance. They have the option to look at different i-joist series, different thicknesses of the OSB floor panels, etc. So, at that point, they can maximize the performance and really reduce the cost. And it allows a lot of flexibility is my understanding as well.  

DC: That’s right. Our proprietary software has that functionality, as does our proprietary literature—we cover floor performance for each specific job site.  

GW: Dan, we covered a lot of things today, a lot of great information. So ultimately, BCI joists come with a limited lifetime warranty. What does that mean for our customers?  

DC: That limited lifetime warranty has stood the test of time. 60-plus years, Boise Cascade has been producing products for the marketplace, and we stand behind those products. And what it means for builders and distributors is fewer callbacks and less hassle in the field.  

GW: Thanks, Dan. Great information. Additional information and resources are available at https://www.bc.com/resources/.