I'm going to build a deck roof. I've determined that I need a 90x220 as the upper support beam. The program doesn't seem to have all the dimensions for laminated wood. Is it possible to replace a 90x220 with a 115x180? Tried to find tables where I can see this but haven't succeeded.
115x180 vs 90x225mm
No, they are not equivalent.
You get approximately the same capacity with a 180x140, however, it is not as stiff as a 225x90. So it depends on what has been the determining factor, deflection or capacity against failure.
You get approximately the same capacity with a 180x140, however, it is not as stiff as a 225x90. So it depends on what has been the determining factor, deflection or capacity against failure.
Best answer
If we limit ourselves to rigidity, which determines the amount of deflection and is most interesting in relation to a terrace roof, you need to go up to 190x180 to get a beam equivalent to 90x225.