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sona tubes, big foot, deck beam advice

silver77's picture

Hey,

I'm working on my own place- a real treat for a carpenter! and I love fall...leaves on the ground, DW harvesting the garden, hot tub late at night , that earthy fall smell.

I'm building a deck on the back of our house...I know most guys would put in 6 x 6 pressure treated posts. We're on bedrock and everything runs downhill to the well. No way DW wants pressure treated.

So I putting in sona tubes tomorrow- thinking 10" sona tubes to bedrock...the beam span is 24'-I'm trying to recycle some 2 x 6 cedar fence boards so the beam will be 3 ply 2 x 6

Question: 3 or 4 sona tubes for the 24' span?

Next project-horse shelter-same deal...most guys would go pole barn style 6 x 6 P.T. in the ground,white wood spliced in on top

We're going sona tubes as well with 6 x 6 spruce on top

Questions: 10" or 12" sonatubes-they are going in 4' to below frost

would you put a big foot in?

best connector to use?

Thanks!!

looking forward to the backhoe showing up tomorrow afternoon-we've got more done at home in the last 2 months than we have since we built our new home 10 years ago...that feels good!

silver

(post #108965, reply #1 of 23)

You did not give the span of joist that the beam needs to support.

But for 3-2x6 cedar.

That beam allows a 6 ft beam span between post, you can support joist upto a 10 ft span.
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.
William the Geezer, the sequel to Billy the Kid - Shoe


Edited 10/2/2009 8:54 am by BillHartmann

. William the Geezer, the sequel to Billy the Kid - Shoe

(post #108965, reply #2 of 23)

Thanks Bill,

funny-I was thinking about you-your advice to the guy who asked about the subpanel was so spot-on, I deleted my reply.

the deck is 12'...beam at 10' so the span is 10'...

off hand- if I was to spring for PT 3 ply 2 x8/10 and save a sono tube...what would I need to get away with 3 posts...

silver

(post #108965, reply #3 of 23)

In this case the joist "span" is for determining the load on the beam. At least that is what I assumed until I looked closely at the chart.

And it does not include the overhang. And I guess that makes some sense, but I am not sure that it should be completely ignored. But his is a prescriptive guide. That is it is simplified that will work and might be over kill for some combinations.

This is the guide and it has all kinds of tables.

http://www.awc.org/Publications/DCA/DCA6/DCA6.pdf

see table 3. And I did not answer your question because it depends on the species.

Now you can also gain on the beam post by cantelevering.

I just did that on my deck.

Was able to go from 3 to 2 post.

.
William the Geezer, the sequel to Billy the Kid - Shoe
. William the Geezer, the sequel to Billy the Kid - Shoe

(post #108965, reply #4 of 23)

I use big foot & sonatube for decks i do as it  prevents up lift in frost areas like mine


for pole barns we use pt posts on a patio stone ( down 4 ft ) and a 2' cross piece to prevent up lift

(post #108965, reply #11 of 23)

thanks dude 4:43 am-man you're up early!

(post #108965, reply #23 of 23)

normal puter time for me is 3 to 5 am then eat , read paper & off to work ( if you rest too much you rust ) LOL.

(post #108965, reply #9 of 23)

That's a neat guide, but it uses a live load of 40lb.  I'm not sure what conditions are like in Thunder Bay, Ontario but around here I would be planning on as much as twice that.  Piffin's right, five 2/10's sounds closer to what I would use, although all there are other problems with laminating individual sticks like that.  Grace's Vycor-like product for decks would be a good idea to keep water out of those joints.

(post #108965, reply #10 of 23)

Here's a link for deck structures in Duluth, Minnesota. Should be pretty similar to Thunder Bay. http://www.duluthmn.gov/building_safety/general/Decks%20Packet%202007.pdf

(post #108965, reply #12 of 23)

Thanks-that's right on

silvr

(post #108965, reply #13 of 23)

In Florida they would want engineering and a stamped set of plans.

Greg

(post #108965, reply #14 of 23)

It's the same here in Thunder Bay,Ontario-except we live in the bush in an unorganized township so no inspectors.

Code is minimum so I always meet code...I was trying to recycle 2 x 6 cedar to save money on my own place but given what piffin said-

I'm springing for new material

silver

(post #108965, reply #16 of 23)

I would save that cedar for something else and get a more hardy species for your beams. Around here that is SYP but I assume you use something else in the Great White North.

Greg

(post #108965, reply #17 of 23)

Piffin and gfretwell

Have to admit...I was in stupid/frugal mode-paid big bucks for the cedar in it's day for a horse fence; put up a new fence and took the old cedar fence apart...

using it for a deck was a dumb idea-I'm going to use it for a dock for the pond-that's another project...

working at home- time but no money ok-screw head on

all new material

4 10" sono tubes on bedrock 8'-0 o/c

2 2 x 8 beam x 24' with Grace Vycor cap (or equivalent) on top of beam

2 x 8 P.T. joists 16" o/c spanning 10'

1" radius edge cedar decking

I've attached a few pictures of site and view.

Anyone have a good flashing to house detail?

I do mostly finish work-reckon I havent' built a deck for 10 years-time flies when yer havin' fun.

thanks to everyone for their suggestions and tuneup-

cheers,

silver

(post #108965, reply #18 of 23)

1 pic is worth 1000 words-can't seem to attach pictures.

silver

(post #108965, reply #19 of 23)

I am using the detail shown on page 8.

I have T1-11 and flashing is tricky. And since it is flat I will just bolt through the ledger, spacers, sidinging and into the house rim joist.

.
William the Geezer, the sequel to Billy the Kid - Shoe
. William the Geezer, the sequel to Billy the Kid - Shoe

(post #108965, reply #20 of 23)

Everything on your list looks good except the beam; 2 2x8's is insufficient for an 8' span, imo. I would be using 3 2x10s minimum, more likely 3 2x12s, depending on the budget.


As far as flashing, my standard practice is as follows;


Ledger, 2x8 if that's what you're using for floor joists, bolted 16" o.c. I stagger the bolts high/low in the joist bays, laying out so bolts fall in center of joist bay. If clap, shingle, or vinyl siding, where I know what I'm dealing with and can go right against ply/ rim joist, I would go around 5" x1/2" HD galv bolt w/ washer. Some here would argue that it needs to be thru bolted; I disagree with the exception of manufactured rim w/ I joists, but it's all good. Grace I&W behind the ledger, extending 6" in each direction. Z flashing (drip cap) on top of ledger, with strip of vycor on wall, lapping onto flashing leg that is against wall. I typically nail the ledger on first, 16d HD galvy hand nails, 3 every 16" o.c.


Good luck


Bing

(post #108965, reply #22 of 23)

Right on,Bing.

The info is bang on...and I'm good at following directions.

Thanks,

silver

(post #108965, reply #21 of 23)

Thanks for the link,Bill.

I'll check out page 8.

silver

(post #108965, reply #5 of 23)

"if I was to spring for PT 3 ply 2 x8/10 and save a sono tube...what would I need to get away with 3 posts..."

It sounds like you are TRYING to under-engineer this deck for a HOT TUB which is a HEAVY LOAD.

Go five posts and 2x10

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #108965, reply #8 of 23)

sorry-the hot tub isn't on the deck...it's on a concrete pad so the deck will run up to it from our bedroom door

(post #108965, reply #15 of 23)

still, 2x6 is not enough to span 12' for the joists 
 
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!


Edited 10/2/2009 2:50 pm ET by Piffin

 

 

Oh Well,

We did the best we could...

(post #108965, reply #6 of 23)

eh, Bill, 4 posts would give an 8' span.

(post #108965, reply #7 of 23)

You are right.

I have too many things on my mind right now.

.
William the Geezer, the sequel to Billy the Kid - Shoe
. William the Geezer, the sequel to Billy the Kid - Shoe