What is the thickness of the OSB subfloor to span 20.5" meet maximum deflection of L/720?
552283
First of all, a maximum deflection of L/720 (I think) is a bit of an "overkill" if you are designing a floor for residential use. I believe the code allows us to use a minimum of L/240 deflection for our floors joists. A stronger design deflection criteria of L/360 for our joists is more than sufficient to carry a live load of 40 pounds per square foot and a dead load of about 15 pounds per square foot.\n\nResidential codes require a minimum of 1-1/8" thickness for both the deck and subfloor. We normally use 1/2" decking under a 5/8" thk. sub-floor for joists spaced at 12" and 16"  o.c.\n\nI understand that spacing your floor joists (or your floor trusses...a truss is a structural system made up of horizontal, vertical and diagonal members joined together to act as a single member....are you really using trusses on your floor?) at 24" o.c. is more economical than spacing them at 12", 16" or 19.2" o.c. Assuming you are using 12" square tiles (granite), the spacing between the joists would only give you 2 tiles on that spacing. I don't think that you would need a subfloor thicker than 5/8" if you have a decking of 1/2" underneath. The sheathing's (plywood or OSB) main use is to distribute the loads unto the joists. I don't think two tiles will deflect that much in a spacing of 24" o.c. Besides, the deck and the subfloor are laid out in a certain pattern (which I assume you already know) that will make it stronger and thus have some fire rating qualities. \n\nThis means that you need not worry too much regarding the thickness of your sub-floor as long as you install the minimum thickness with the minimum decking thickness required. What you should worry about is if your joist (or your "trusses" as you term it) will be able to carry the load superimposed on it and be able to transfer these loads into the supporting walls (or beams, which is another question) and unto the foundation wall or footings below.\n\nMy suggestion, since your question is a bit unclear (what is the use of the floor, is it for residential or commercial, is it located on the first floor or on the upper floors, is it to be used as a cantilevered balcony or a supported deck,  is it to be used for the exterior or interior since exterior use may mean snow load, etc.)is for you to call the tile manufacturer and give you some answers giving them the description of how you plan to lay out your joists (trusses).\n\nI am an architect and one thing I always remember regarding structural questions....if I can't do it myself, let the manufacturer do it for you (be sure to put their answers in writing) or better yet, ask a structural engineer.
731102
consider the front face to be an A by A square that has depth length L.  The Volume of this rectangle would then be A*A*L.  since we know A + L =108. Then L = 108 - A.  Putting this into our volume formula we get 108A^2 - A^3.  In order to maximize A take the derivative and set it to zero.  So we have 216A - 3A^2 = 0.  This leads to A = 72 cm.  Then L would be 108 - 72 = 36cm.  The maximum volume would then be 72 * 72 * 36 = 186,624 cm^3
158652
If the bar has a square cross section, it's \n\n12*0.28 = 3.4 lbs/linear foot.\n\nIf the bar has a circular cross section, it's \n\n12*(pi/4)*0.28 = 2.6 lb/linear foot.\n\nIf the bar has a more irregular cross section, the way to do it is to multiply the cross-sectional area (inches^2) by the length (1 foot) by the density (0.28 lbs/cubic inch).
365112
It's difficult to find a plywood any thicker than 3/4", hardwood or softwood. In dimensional lumber measurements, 1" is usually referred to as 5/4...but that's not plywood.  You might try WoodPlanet at www.woodplanet.com ... They have 1" thick sheets of 4'x8' hard maple plywood, A/A grade, good on both sides, which sounds like something you might be looking for.
105365
Ya the number 1s 320\nBut who in the world has a perfecr floor???\nPlus you dont know how the room is \nWhen doing a floor you want a reveal the same on all 4 side if you can to make it look right. \nYou would not want a tile 4inch on this end and 8 on the other.\nSo then is you do the math its\n320+16+20=356total\nthis will make sure that the floor looks correct and your not short\nI have been in the field 20yrs+ and trust me you never buy just what you need.\nIf you did that and you need 10 more pc and you went back the tiles would be from a differnt batch and not match up right.\nGoodluck
326112
20 inch flatscreen wide is best.\n\n-J
431522
http://floorforwindows.generalentropy.com/Index.aspx
923963
Traffic timing for this much weight is also considerable. A\n   building code shows that you might need 15 or more for\n   this area so titanium is probably out.  The core value of\n   bronzed steel is ok for the average busy building.  Size again\n   must be measurables ranging from 2.7 to 3.7 made in 20 foot\n   can be made in 35 precise.
190951
5/8 in thick for the rim and 10 feet off the floor.
472372
not very good. the osb market is expected to increase over the next several years pushing out plywood.  plywood manufactures are going to have to up grade to more modern equipment in order to stay in business.  most plywood co's will have to go to nich markets that osb can not compete with
63808
30' feet deep by 160' wide...
371498
About the same as any raised floor.  Posts, beams, joists, decking.  There are guides for this at lumber places.  Also check local codes, they ALL vary.
1114413
Using natural 20 inch soles!
398806
here is one of the datasheets available on the internet:\nhttp://www.ee.washington.edu/stores/DataSheets/74ls/74ls73.pdf
725266
12 x 16, that will equal square feet (192)\njust measure length times width to calculate square footage
923734
The Slabb X10\n\nhttp://www.affordablekiosks.com/productDetails.jsp?product=33
616105
check with the OSHA department in your state.  They can give you a better answer than what you'll get on YA.