I'm considering using these. Seems you can get longer spans out of them than with 2x12s (would be using 14" or 16" deep i beams). Also, since the web is only ~3/8"-1/2" thick there would be less of a thermal bridge if using these for rafters with foam insulation on a cathedral ceiling.
Any negatives to using these?
Thanks!
I used them for my floor joists. I thought they were great - dead flat with no cup, twist, or bow. Careful walking on them till you get the subfloor down - they'll roll on you.
I have used them as floor joists in my cabin and were really easy to use. I was able to span my 18 foot distance without a center beam. Floor seems real solid. I did not use them as rafters but have looked at a number of structures on-line that did. They are tricky to cut and I would guess attach (I think there are some special brackets needed). They are also a little wobbly when laid on their side.
I used some 20' ones for floor support beams and a couple of 18' ones for some floor joists, but only because I got them so cheap.
They also allowed me to design for a cabin width of more than 16' and for a 16" bumb out without getting extra long 2x's.
There would be some thermal bridging advantages, but they won't last as long in a fire as regular 2x's.
They were a real pain when mixing with 2x's; so I don't recommend that. Had to do a lot of fitting.
You just have to be careful with deflection calcs. to prevent too much bounce.
I'm almost sorry I got them so cheap. Like the design concept though.
I used them for floor joists in my 24x34 along with 3/4 OSB T&G for the subfloor----floor is dead level and absolutely bounce free. Used per manufacturers instructions, they have many advantages over 2X lumber and can definitely handle longer spans.
What were the prices that you guys got them for? Also length and depth?