That means instead of 1 member per 24", you need 3 members per 24". So you'll need to double the member count for the loading, and add another 50% to reduce the deflection. Now you have twice the load (40 psf live, 20 psf dead) and need 2/3 of the deflection (L/360) compared to the table parameters. It tells us that (if douglas fir is your preferred species) DF #1 2圆 24"o.c. Start with 2018 IRC table R802.4.1(2), which is a span table (for rafters) for 20 psf live load, 10 psf dead load, and L/240 deflection. With a bit of reasonable extrapolation, you can do this via the span tables. So you should just consider your hacked up 2x8s to be oversized nailers and install new members that will be sufficient for the load and span on their own. In which case you no longer have that grade. For example, if you start with a particular grade which might allow knots of a certain large size as long as they are at least 2" from the edge of the member, and you remove 2" from the bottom of the member, now you may have a large knot right at the bottom edge of the member. Hence I need a table.Īny advice on whether my plan to gain some height in the basement is a bad idea would be greatly appreciated!Ĭlick to expand.If you hack up your 2x8s, it's difficult to assign design values to them, as they will no longer be graded. Or rather than replace the existing joists, I will just sister each of the 2圆 joists to the existing 2x8 joists and trim off the bottom 2 inches of the 2x8's, thus getting at least as good as 2圆 joists at 12"Īccording to the IRC 2018, I can even use 2圆 Douglas fir-larch for this, but I was wondering if the LVL's will be even better (stronger and with less bounce). The reason I want to know thei is because I want to replace the basement ceiling (=kitchen floor) joists, which are 2x8 at 16", with 2圆 LVL joists at 12" so that my basement height will be 7' from finished floor to finished ceiling (after I finish it). SO I assume that Boise Cascade VERSA-LAM 2.0-3100 LVL can do better? Is it true? Both will account for all the criteria, but I think the way StruCalc does it makes it a little clearer.The IRC 2018 table R502.3.1(2) shows for Douglas fir-larch (the strongest lumber listed), a 2"圆" with 12" spacing can span 11' 4" (!) for dead load = 20psf and live load = 40psf. They also divide beams into several categories, where beamcheck just has one. StruCalc has modules for columns (including lateral loads) and footings. Beamcheck also only sizes beams, not footings, posts, etc. StruCalc appears to have more choices, and has all the data already included. I've never liked it that Beamcheck makes you enter the values for LVLs yourself. ![]() StruCalc is a little less user friendly interface, but appears to be much more complete than either ConstructionCalc or Beamcheck. That means I had to downgrade my Excel Security settings from High to Medium. Another problem for me is that this software is written entirely as very sophisticated Excel Spreadsheets with unsigned macros. However, I think the loads calculator module, available separately, may be worth buying ($54 as a download) for those of you who have some trouble with that. Well, I've reviews both ConstructionCalc (purchased) and StruCalc (demo, not 100% functional).ĬonstructionCalc does not have all the LVL's I need. Being a PITA does not get your work done faster.īecause I am not licensed I can't get liability insurance nor do I charge as if I was licensed - so as much as I would like to learn how to size beams and footings - I am thinking I might be better off never touching that can of worms. ![]() Needless to say his project suddenly moved to the bottom of the pile. I told him I'm not his project manager or an engineer and don't get paid nearly enough to do those services for him and he calmed down. Then he wanted me to put down in writing everything that might go wrong with his project! Then he FREAKED out and started complaining about stuff he was completely happy with a couple days ago. ![]() So I told the builder I don't do structural calcs on stick framing. (After some helpful guidance from a resident curmudgeon). I was trying to do some simple calcs on a simple house but realized I was definitely over my head. This thread is SO timely! I was just wondering about these structural calc softwares.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |