Sorry, I don't speak the language.


  #1  
Old 10-27-02, 01:28 AM
amitch02
Visiting Guest
Posts: n/a
Sorry, I don't speak the language.

Let me try again.

My deck will be 14'x16'. I have two 14' beams made of 2-2x10. Each beam is suported by 3 posts (girders) spaced ~6' apart set on concrete using post achors. The two beams are 12' apart from each other and run perpendicular to my house and the joists will be parallel to the house.

Each beam is level but is not level with each other. I can not raise the lower beam or lower the higher beam. -- Don't ask ... a long story.

My question is can I replace one of my 2-2x10 beams with a 3-2x8 beam.
 
  #2  
Old 10-27-02, 05:17 AM
L
Member
Join Date: Mar 2000
Location: Arlington, WA
Posts: 9,238
Likes: 0
Received 1 Like on 1 Post
Your 2 beams (girders) are 12' apart? What are you planning on using for joists? (That is my question, now to yours)

The 2 girders are level, but at different heights. Each is supported by 3 posts. Can you make the posts supporting the lower girder taller, raising it the amount you need to?
 
  #3  
Old 10-27-02, 08:23 PM
amitch02
Visiting Guest
Posts: n/a
My joists are 2x8s - 16" o.c. and 5/6 x 6 decking

I can't raise one beam because the deck will then be above the door jam. I can't lower one beam because it already rests on the post anchors.
 
  #4  
Old 10-27-02, 10:05 PM
L
Member
Join Date: Mar 2000
Location: Arlington, WA
Posts: 9,238
Likes: 0
Received 1 Like on 1 Post
You have a choice to make. Since you can't raise the lower girder, you need to lower the girder that is too high. That means taking it out and pouring new footings for it. The alternative will be to have the deck run uphill! Your choice.

Spanning 12' between the girders with 2X8's at 16" O.C. I wouldn't do it. And putting "5/6 x 6 decking " (I am assuming that you mean 5/4 X6) across joists at 16" O.C. -- I wouldn't do that either.

Here is a solution that will save you a whole lot of work.

Get rid of the 2X10's that you have for girders. Replace them with 4X6's, leaving your footings in place. Put in a third girder, half way between the 2 you already have. Make sure (this time) that not only are these girders level, but they are also at the same height! Since you apparently already have the 2X8's for the joists, use them. (2X6's would have done just fine though). Just add more of them and put them 12" O.C.

Here are my reasonings.

This is an EXTERIOR structure. While 2X8's can span 12' (barely) in an INTERIOR application, in time, in an exterior application, they will get weak, and you will get sag in the deck. Span then 6', and they will not sag in their lifetime. Spacing the joists at 16" O.C. using 5/4 decking will result in the boards feeling springy. You won't notice it when the deck is new, but (trust me on this one), you won't like things in 5 years!!
 
  #5  
Old 10-28-02, 06:22 PM
amitch02
Visiting Guest
Posts: n/a
I guess I won't ask the experts?? at Home Depot anymore. It is more work (hole digging) but I do want to build it right.

Thanks Lefty.
 

Last edited by amitch02; 10-28-02 at 09:46 PM.
  #6  
Old 10-29-02, 03:06 PM
L
Member
Join Date: Mar 2000
Location: Arlington, WA
Posts: 9,238
Likes: 0
Received 1 Like on 1 Post
If you get rid of the 2X10's and go to 4X6's for the girders, you won't have to do any digging. Using your existing footings, you will be able to cut posts to mount the 4X6's on, and by varying the heights of these posts as needed, make each of the girders level as well as getting them all at the same height.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: