Replies

1. 
   Jencar | Dec 23, 2003 07:33am | #1

   3/4" oak T&G over 3/4" ply...adds up to 1 1/2" of flooring goodness..

   We have 1/2" T&G oak over diagonal 1X subfloor...the oak runs parallel to the joists. Plenty strong.

   Jen

1. 
   JohnSprung | Dec 23, 2003 09:46pm | #5

   Mine's 5/16" t&g oak over diagonal 1x.  Most is perpendicular to the joists, but some is parallel.  That was the reason in the old days that 1x was laid diagonally, so you could put the finish floor on either way, depending on the shape of the room or hallway.  Being diagonal probably also helped with cutting the wild ends of subfloor off at outside walls and stairwells.  In those days there were no hand held electric saws, so this was done with a hatchet.

   -- J.S.

1. 
   slykarma | Dec 24, 2003 04:39am | #9

   John,

   The reason 1x subfloor (and wall sheathing too) was run diagonal to joists was to laterally stiffen the floor (and wall) system. The sheet products we use today do the same thing. Running the subfloor at 45 had its disadvantages since effective span between joists is 40% greater than running at 90 to them. Hence you typically see joists @16" o/c to give effective span of 22 5/8".

   Wally

1. 
   JohnSprung | Dec 24, 2003 05:23am | #11

   Though running the subfloor 1x diagonally does have the effect of increasing the platform's resistance to racking out of square, that was at best a secondary side benefit in the thinking of those pre-Long Beach quake days.  If racking were a concern, they would have nailed to the blocks, not just the joists.  As it is, the racking resistance increase is only significant near the ends of the joists, where the joists, subfloor, and a continuous band joist meet. 

   I haven't measured, but I doubt that my subfloor is more than 30 degrees away from perpendicular to the joists.

   -- J.S.

2. 
   Jencar | Dec 24, 2003 09:34am | #13

   A-HA! That makes sense...if I had my druthers I'd pull up all the diagonal subfloor and put down 3/4" ply...

   A lot of cold air comes up between all those gaps, and being in SoCal, under-floor insulation is pretty rare.

   Jen

1. 
   RobKress | Dec 24, 2003 04:28pm | #14

   It doesn't have to be rare in your house Jen.  Wouldn't it be easier to just insulate than pull up the entire floor?  Better yet, hire someone else to come in and insulate.... no mess inside, no stinky, ugly guys like me tramping through your house....

   Rob Kress

1. 
   xMikeSmith | Dec 25, 2003 06:17pm | #15

   somebody wanted this bumped to the top...Merry Christmas !Mike Smith   Rhode Island : Design / Build / Repair / Restore

2. 
   Turtleneck | Dec 23, 2003 02:28pm | #2

   I take it that you want to run the entire floor in the direction of the joists because of the hallway?

   Personally, I go for function over design. So if it were my floor, I would NOT run the flooring in the same direction as the joists.

   If however, You were paying me to do your floor... I would run in the direction of the joists, but I would not guarantee the job and I would probably have you sign a waiver and pay me in full before I started.

   However beautiful the strategy, you should occasionally look at the results.    Winston Churchill 

3. 
   MisterT | Dec 23, 2003 02:41pm | #3

   OK, I'm only going to say this one more time!

   Oak (or any flooring, hardwood or not ) is a FINISH material.

   It is not structural!!!

   Sure it will be Marginally stronger if you lay it Perpendicular to the joists.

   But Your Subfloor is what should be made adequate to provide the desired performance.

   Hard wood should be layed parralell to the long dimension of the room for expansion considerations. (And because it looks better)

   If you feel that an Oak floor laid parrallel to the joists will not be sturdy enough, then you need to beef up your subfloor.

   Do it right or do it over, your choice.

   Mr T

   Do not try this at home!

   I am an Experienced Professional!

1. 
   rez | Dec 23, 2003 07:25pm | #4

   "And that's the Rest of the story!'

    

    

2. 
   luvmuskoka | Dec 24, 2003 01:55am | #6

   Mr. T?,

   Ya wanna' job?Ditch

1. 
   MisterT | Dec 24, 2003 03:03am | #7

   Make me an offer!

   .....On second thought.........

   You do many waist level floors????

   I can't do the low-down kind any more.

   The floor is a lot farther down than when I was in my twentys.

   Mr T

   Do not try this at home!

   I am an Experienced Professional!

1. 
   Piffin | Dec 24, 2003 04:43am | #10

   Thanks for saving me all that typing.

   Funny how those floors get further away with time.

   Not only more distance, but it is more of a circuitous route!.

   Excellence is its own reward!

3. 
   greggo | Dec 24, 2003 03:46am | #8

   Hey Mister T: I got the same scenario,but I got a sh-t load of 1/2"CDX and 3/4" T&G plywood left over.I was going to use a double layer of 3/4" plywood (to cover me) in case I do any tile in the other rooms.Doe's this sound like overkill?

   Thanks:

   With all my Dogs Love Greg

4. 
   dfk1963 | Dec 24, 2003 06:27am | #12

   Bruce, a major manufacturer of hardwood flooring, voids the warranty of their pre-finished oak floors if they are layed parallel to the joists, (this is 3/4" x 2-1/4" tounge and groove oak i'm talking about here.) Now I'm not really sure that a warranty is worth a hill of beans to me, but I'd like to balance concerns of cupping against those of looks alone. I't is apparently much harder to refinish oak laid parallel to joists due to the very minor 'humping' that can occur--preventing the sanding drum from making full contact.

   Now I'd rather have the floor look right and just want to make sure that I'm not screwing the guy 15 years down the road.