I know there are some enginerds around here. I want to build a loft at the back of the shop. It is 5 feet deep, and 25 feet wide. If at all possible I want to build it without any columns in the middle. What kind of beam would I need to support this thing across the front? I made a quick drawing with Google Sketchup to help. Just copy and paste into a browser window.
http://img221.imageshack.us/img221/3458/garageloftgm0.jpg
Is it possible?
Just a nail driver, but the span tables I refer to indicate you can build a glued laminated 2x4 beam with a height of 9 1/2 to span 28'. Now, LVL will be a little more expensive, but easier to handle. I would opt for the LVL. Transporting it will be a bear. You can site build the 2x4 glued laminated beam.
Originally Posted by chandler
Just a nail driver, but the span tables I refer to indicate you can build a glued laminated 2x4 beam with a height of 9 1/2 to span 28'. Now, LVL will be a little more expensive, but easier to handle. I would opt for the LVL. Transporting it will be a bear. You can site build the 2x4 glued laminated beam.
LVL? Is that an engineered beam? Not familiar with the term. I have a trailer and can transport it no problem. Maybe that would be the best thing to do. Any site you can point me to that would show me build a laminated beam? Making it from 2x4s Would it be 7 2x4s laid on top of each other with the ends staggered? That would make it 9 x 3.5 or so. Would it be better to build from larger stock, three 2x10s sandwiched together or something? Where can I find those span tables?
Sorry, LVL stands for laminated veneered lumber, and is manufactured using thin layers of wood glued and pressed under heat until it is cured. Be prepared, as you will need a 25' trailer to haul it on as it comes in one piece. Site building a laminated beam would make more sense, as you state, 7 glued and nailed 2x4's in a staggered pattern will make up the structural integrity in the span tables. Using a larger dimension lumber will only make it too heavy to handle, and its own added weight will have to be calculated into the total weight of the loft, so minimizing the lumber to what the span tables recommend would be in your best interests. I use the tables in a reference book I have in my office, but I just googled live load span tables and got several sites with good information.
Originally Posted by chandler
Sorry, LVL stands for laminated veneered lumber, and is manufactured using thin layers of wood glued and pressed under heat until it is cured. Be prepared, as you will need a 25' trailer to haul it on as it comes in one piece. Site building a laminated beam would make more sense, as you state, 7 glued and nailed 2x4's in a staggered pattern will make up the structural integrity in the span tables. Using a larger dimension lumber will only make it too heavy to handle, and its own added weight will have to be calculated into the total weight of the loft, so minimizing the lumber to what the span tables recommend would be in your best interests. I use the tables in a reference book I have in my office, but I just googled live load span tables and got several sites with good information.
Thanks. That gives me somewhere to start.
Any changes to structure require submitting plans to Building Code Office and getting permits and require submission of plans. Unless you live in the hinterlands where codes are not enforced, this is a requirement.
Chandler,
Can you double check your span table for the 3-1/2 by 9-1/2 beam. I quickly punched some numbers into a calculator for deflection and it did not look good for a 28' span (I easily could have made a mistake). First, I was fairly liberal with a 40 psf total floor load (or 100 plf) and E = 2000 ksi; the deflection was about 2-3/4. With a little more conservative guesses of 50 psf and E = 1600 ksi, the deflection was over 4.
Notes:
psf - pounds per square foot
plf - pounds per linear foot
E - Modulus of Elasticity, a property of the material. Some times it is abbreviated so E 2.0 = 2000 ksi.
ksi - kips per square inch (kip = 1000 lbs)
Originally Posted by Phil H
Chandler,
Can you double check your span table for the 3-1/2 by 9-1/2 beam. I quickly punched some numbers into a calculator for deflection and it did not look good for a 28' span (I easily could have made a mistake). First, I was fairly liberal with a 40 psf total floor load (or 100 plf) and E = 2000 ksi; the deflection was about 2-3/4. With a little more conservative guesses of 50 psf and E = 1600 ksi, the deflection was over 4.
Notes:
psf - pounds per square foot
plf - pounds per linear foot
E - Modulus of Elasticity, a property of the material. Some times it is abbreviated so E 2.0 = 2000 ksi.
ksi - kips per square inch (kip = 1000 lbs)
Thanks for looking out! My span is 25 feet, so that may make a bit of difference.
PhilH, the tables I was consulting allowed 51 psf load and a span of 24', and a reduced 32 psf with a span of 28'. Now, I wouldn't recommend this to be the only support in the loft by any means. I still advocate the LVL, although unwieldy.
Correct me if I missed something but what are your building dimensions again?
25' x ? Make sure you aren't running the joists the wrong way, but if 25' is
the shortest run, you may want to look into open joists which are
incredibly strong.
Check out this link for span info:
http://www.ufpi.com/product/oj/prod/faq.htm
Originally Posted by carouse2
Correct me if I missed something but what are your building dimensions again?
25' x ? Make sure you aren't running the joists the wrong way, but if 25' is
the shortest run, you may want to look into open joists which are
incredibly strong.
Check out this link for span info:
http://www.ufpi.com/product/oj/prod/faq.htm
25' long, 5' deep.
There is a link in my original post that will take you to a drawing of what I want.
Looking at the page you posted. Very interesting. Looks like for a 25' span I would need 14 tall open joists, though? I'm loosing a lot of space quick. With some sort of beam it looks like I can save a few inches.
According to my KeyBeam software I use regularly, a quad 1-3/4x11-7/8 LVL will be adequate. This will give you an L/703 with a .42 of deflection. I set the loading to L/480 240 and 40 live 10 dead.
Originally Posted by chandler
Just a nail driver, but the span tables I refer to indicate you can build a glued laminated 2x4 beam with a height of 9 1/2 to span 28'. Now, LVL will be a little more expensive, but easier to handle. I would opt for the LVL. Transporting it will be a bear. You can site build the 2x4 glued laminated beam.
What kind of glue would you use on a this kind of beam? Construction adhesive? carpenters glue? Thanks
Tags: beam, need, span tables, laminated beam, build glued, build glued laminated, build glued laminated beam, glued laminated, glued laminated beam, little more, Originally Posted, beam with, beam with height
