Replies

1. 
   scotclarke | Mar 27, 2002 03:56am | #1

   I know truss joist macmillian has a span book that is stapled to the joists .Wearhauser i'm about 80% shure also has a book on joists and span calcs.

2. 
   TomMoen | Mar 27, 2002 04:08am | #2

   2x6 should be fine.  Any bookstore will have a book with a span table.

   Tom

1. 
   JohnSprung | Mar 27, 2002 04:22am | #3

   My back deck joists are 2x6 on 16" centers spanning 5'-6", so if you mean the joists run 5", you should be fine.

   -- J.S.

1. 
   desirednam4 | Mar 27, 2002 04:38am | #4

   OK... Rule of thumb here...

   Lumber (W-2)2=max span in feet...

   ie. 2x6 lumber... (6-2)2=8 feet.

   2x10... (10-2)2=16 feet.

   Lakeside...On the mountain, near the stream,aj Builder of Fine Homes & Tennis Courts Great Camps of the Adirondacks

   Edited 3/26/2002 9:43:52 PM ET by aj

1. 
   coonass | Mar 27, 2002 04:45am | #5

   Try http://www.southernpine.com/tables/

   KK

2. 
   BossHog | Mar 27, 2002 03:15pm | #6

   I prefer to go 10 times the depth. It's little more conservative.

3. 
   ProDek | Mar 27, 2002 05:40pm | #7

   (2x6 = 6')  (2x8= 8')  (2x10=10') That would be from ledger to beam. You should be fine with 2x6.

   Bob

   "Rather be a hammer than a nail"

1. 
   desirednam4 | Mar 27, 2002 08:58pm | #8

   Pro deck... or should I call you... Mr. Overkill.... Yes... decks need to be strong for huge parties and hot tubs.... so your numbers are great.... but my rule of thumb is what works for all living floor space that I build and for 99% of the decks and porches I would ever build.Lakeside...On the mountain, near the stream,aj Builder of Fine Homes & Tennis CourtsAnd featuring; Great Camps of the Adirondacks

1. 
   JeffOps | Mar 28, 2002 04:21am | #9

   aj,

   Deck..... Porch..... Living room.....

   Which of the three is unlike the other two ? Bob's advice applies better to a porch than to a living room.

   Call him mr overkill if you want, but he has an awful lot of experience with decks and porches. And the subject at hand is a porch, not a kitchen/bath/living room/bedroom. You never know when someone is going to decide to bring an engine block up onto the porch, on an engine stand, and work on it out of the rain. (And leave it there for months.) Or, the mrs decides that she likes the idea of a ceramic pot 4 feet across and 3 feet deep with an avacdo tree in it, being placed on the porch.

   Then, of course, there is that odd person who actualy regards the porch to be the same as a deck and has that huge party and hot tub on the porch as well. LOL My name is Luka.

1. 
   coonass | Mar 28, 2002 04:59am | #10

   I don't know what a full cord of firewood weighs but it made a deck I built sag. 2x8 spanning 7'. Now I ask what's gonna be on the deck.

   KK

2. 
   ProDek | Mar 28, 2002 06:38am | #12

   Luka-I like your new HammerBob

   "Rather be a hammer than a nail"

2. 
   ProDek | Mar 28, 2002 06:31am | #11

   aj- I like overkill-and the formula is easy to remember

   In the foothills away from the streamBob

   "Rather be a hammer than a nail"

1. 
   desirednam4 | Mar 28, 2002 05:54pm | #13

   Hey.... I like your formula for you and your pro decks. I may start Pro deck East and will make it our fomula here in the East Too!

   Off to get the marketing package done...

   Probuilt Adirondecks... with a Western Influence...Lakeside...On the mountain, near the stream,aj Builder of Fine Homes & Tennis CourtsAnd featuring; Great Camps of the Adirondacks

1. 
   xMikeSmith | Mar 29, 2002 06:01am | #14

   your rules are fine for where you're building , aj.. but a lot of places have adopted 60 lb/sf for decks... and your's will not comply with that...

   RI has been 60 lb/sf since about 1990.

   Mike Smith

   Rhode Island : Design / Build / Repair / Restore

2. 
   Piffin | Mar 29, 2002 06:41am | #15

   Why is that? do you suppose?

   Excellence is its own reward!

   
3. 
   JeffOps | Mar 29, 2002 07:09am | #16

   Hay lookit !!!

   There's somma dem there yoofows over the trees behind piffin's house !!

   My name is Luka.

4. 
   blindfreddee | Mar 29, 2002 11:45am | #17

   Why should " the borads run perpendicular to the wall that the porch resides against.  Therefore, the joists should run parallel to the same wall."?

   For what reason?

   For example, the porch is 5 deep by 18 feet wide.  The joists should be 18 feet long.  adding beams beneath the joist lengths would reduce the joist size by reducing the length of free span between these beams.

   Why?

   Why not run your joists the other way, which gives a span of 5 feet thus eliminating the need for any beams commonly known as bearers?

   Perhaps you should stick to satellite dish installation and let the pros give out the advice.

1. 
   xMikeSmith | Mar 29, 2002 07:56pm | #18

   how many other states have adopted 60 lb/ sf for decks ?Mike Smith

   Rhode Island : Design / Build / Repair / Restore

1. 
   mikeyarnold | Mar 29, 2002 08:23pm | #19

   I just looked and it appears that Wisconsin is 40 psf for live load. (Wisc 21.02 (1)b.)

2. 
   Piffin | Mar 29, 2002 09:51pm | #20

   Dear fearlessly blind freddy,

   You won't find much of any body any more professional, even if we are all a litle diverse here so take it easy.

   The reason many of us try to design a deck to use joists running parallel to the wall is to have the deck boards perpendicular. you do the elevation so there is a slight pitch away from the building. That way you provide rain a good chance to run off away from siding and the foundation. Not every one does this and it is neither right or wrong but it is good.

   When I do it, which is about nine times out of eight, I place a beam at midpoint of a span like this so that it is really only spanning 9 feet. I can flush mount or undermount the beam depending on other desigfn requirements.

   If I want to keep the deck facia smaller to look at I may use 2x6 @ 12" OC instead of 2x8@ 16" OC

   Remember, you are designing the whole thing to a load rating, like Mike pointed out, and not to a span or a budget.

   Excellence is its own reward!

1. 
   blindfreddee | Mar 30, 2002 05:14am | #22

   fair comment

1. 
   JeffBuck | Mar 30, 2002 06:10am | #23

   Hey BF...U R A dum a$$! bet yer porches are darn purty! Ha Ha HA HAAAAA! I love it when an idiot exposes himself! Jeff

      *  Jeff J. Buck/ Buck Construction/ Pittsburgh, PA  *    

   2nd Generation Buck Const, 3rd generation Craftsman                         

   Edited 3/30/2002 2:33:34 AM ET by Jeff J. Buck

3. 
   richdes | Mar 29, 2002 11:52pm | #21

   Well, Pete actually brought up a very valid point. If you are using T&G decking/floor boards they should run perpendicular to the house wall, the reason is for water drainage. If it is a porch with a solid floor of T&G then it should be pitched slightly for run off. If the floor boards are parallel to the house then the water is constantly running into the joint. They will last much longer if run the other way.

   Every region has its own jargon, I call them beams to, sometimes I even call them girders

   Rich

   W

5. 
   TooManyTools | Mar 30, 2002 10:42pm | #24

   Try this

   http://www.cwc.ca/design/design_tools/calcs/SpanCalc0399/Span_US.htm