I will be starting construction this spring on my 3000 sf home in Malvern, PA.
Foundation will be 10′ Xi Superior Wall, exterior walls Nascor EPS wall panels from Canada and roof will be conventional trusses. TJI’s were specified by the architect, but I am considering using the Openjoist 2000 system. Anyone have any experience with this type of floor joist? Also considering having the floors panelized offsite and installed with the crane after the Superior wall foundation is installed.
Thanks in advance.
John
Replies
Never used them, but for my current project I priced OpenJoist 2000, TJIs, and open web metal plate floor trusses. That was the order in which they came in price wise - the OpenJoist being the most expensive. I was shocked that the metal plate trusses were the cheapest, especially since that is what I really wanted to use for running mechanical, plumbing, etc. How often is your first choice the cheapest? :-) The down side of the open joists for my application was that they were only readily available in 12" and I wanted 14" for the forced air ducts. I also asked one of my co-workers about the OpenJoists - he said that he had used them once and felt there was too much deflection. If you think you are going to use them, you might want to compare deflection specs carefully: ie. L/480, etc. BTW, there is more to it than that.
Also, another brand of essentially the same thing is TrimJoist.
I used Openjoist 2000 in my "dream" home in 1999. They worked great. Easy to use, no shrinkage or squeaks. Made running wiring and plumbing a breeze, though they did not have enough open depth for ductwork, but then again, neither do any of the alternatives.
They are nice because they are trimmable in the field up to 11", I believe.
Since they are engineered, the deflection is quite predictable and tabulated by the manufacturer.
If you use them, make sure they are all installed in the same direction. Depending on the length they are slightly unsymmetrical, and if you get one of a series flipped around then the openings don't all line up and it could interfere with running plumbing in a straight line.
When using any engineered joists, the rim joists must also be of engineered material. If you use solid dimension lumber it will shrink to a much greater extent and transfer all the compressive load to the ends of the joists.
Sounds like you are very interested in insulation. Also consider raised heel trusses, which allow attic insulation to remain full thickness all they way to the outside of the exterior walls.
I used OJ2000's in my house. They were a couple hundred bucks more expensive than TJI's, but when you factor in all the hole drilling and cutting labor for electrical, plumbing and staple-up radiant, they wound up being a lot cheaper. I found them to be very easy to install, very consistent in sizing, and easy to handle.
As for deflection, I consulted their charts, which told me I could use the 9-1/2" joist for my application. I used the 11-7/8" because it worked better for the design, and I probably should have used the 14" to get even more space in the ceiling. I don't see any issues at all with what I have.