# Support Question?



## woodbutchr (Jul 31, 2007)

I got a deck to build that will be 7' off the ground. Under the deck is an old flip up garage door with a 12' wide concrete pad in front of it that will have to still be accessible. The deck will hold a 4 person hot tub pretty much right above the garage door. I was going to use 2" x 10" joists @ 12" with two tripled 2" x 12" beams @ 5' & 10' perpendicular under the joist. (the deck comes 12' out)
Well now the HO wants all the headroom he can get so he is not in favor of the tripled 2" x 12"s. He suggested using 6" x 6" posts as beams @ 2' under the joists with 6" x 6" posts to support them. The post "beams" will have to span 13'. I don't know if I feel comfortable with his idea but he will gain about 6" headroom doing it this way. 
Just wanted ya'lls opinions on support with the the most headroom?


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## Jason Whipple (Dec 22, 2007)

I would start with getting the weight of the tub add 7 lbs. for each gallon of water it holds and then add around 180 per person. That will give you the total load you need to carry.

Most lumber yards have load/span charts for lumber. Use them to find out what you need. If it gets under built, you could have some real legal problems down the road if it goes down! Be careful about doing what the H/O "wants" and make sure you do it right.:thumbsup:


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## Jason Whipple (Dec 22, 2007)

Here's one.........

http://www.southernpine.com/spantables.shtml


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## woodbutchr (Jul 31, 2007)

Hey thanks for the span info. I totally agree with avoiding what the HO wants, I told him that I won't do it his way if the loads/spans don't pan out right.


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## Jason Whipple (Dec 22, 2007)

If it's important to them you might have to jump it up to steel "I" beams, but that gets costly!


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## woodbutchr (Jul 31, 2007)

Where can I find out how much load/span a 6" x 6" will carry? Everything I have just details 2x lumber.


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## neolitic (Apr 20, 2006)

4 member 2X6 laminated beam will
be stronger than a single 6X6, as 
the 6X6 likely will be sawn from 
the center of the tree and the 
grain isn't ideal.
That said, one doesn't gain much 
by adding width as compared to
depth.
I'm guessing your quadruple 2X6
is about the same as a double 2X8.
Use Google, you will find tables.
Like Jason said, if you go to a
lumber yard you'll find tables
there too! :thumbsup:


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## BuiltByMAC (Mar 11, 2006)

Your original plan of 2x10 joists and triple 2x12 beams could still work.
Move the triple 2x12 beams up level w/ ledger and hang your joists off each side. That gets you a 13" thick deck structure (decking + beams) w/ posts off to the side of the concrete pad. Running 2x6 or 2x8 cross bracing on the flat under the 2x10 joists wouldn't add to the thickness because the joists are shallower than the beams. 

That being said, it sounds like you're "figuring" what size beams/joists/joist spacing in your head...

I'd strongly suggest taking your design w/ spans and desires for headroom to an engineer. Pay them to figure the beam sizing/joist spans so you can have that stamp on the project. They'll also come up w/ recommendations for stabilizing the structure for lateral sway.

Hot tub manufacturer will have total weight of hot tub filled w/ water & people... take that info to the engineer.

Mac


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## RenovatorLLC (May 14, 2008)

*Take it to an engineer for approval*

I can't imagine this not being a permitted project. And if so, the Building/zoning department will most likely want an engineer's stamp of approval for its intended purpose. Although an engineer isn't required for a standard deck, when you start adding hot tub point loads, the Building Dpt get really interested, at least they do up here.
Having a structural engineer you can turf the calcs and plans to prior to submitting the plans for approval really speeds up the process, and removes the liability for the design (structurally) off your shoulders.
I usually get the engineer in the design phase, prior to presenting the draft tot the client. The engineer will determine the structural boundaries to your design.


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## neolitic (Apr 20, 2006)

Some of us don't have deep enough
pockets to pay an engineer for design
work before the HO gives a go.
It's not all bad to have a grip on what's
doable before taking it to pay for a stamp.

What I can't understand, is not being willing
to do the research to get to that point.


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## RenovatorLLC (May 14, 2008)

neolitic said:


> Some of us don't have deep enough
> pockets to pay an engineer for design
> work before the HO gives a go.
> It's not all bad to have a grip on what's
> ...


 
The engineer I use is a good friend, and I've done considerable work on his house, so the situation is more ideal, and not your usual relationship. I can ring him anytime with questions, such as this one, and he will give me a verbal answer. That way I have a fairly good understanding of the requirements prior to drafting a proposal.


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## woodbutchr (Jul 31, 2007)

Well I don't have an engineer in my pocket for whenever I need one so that is out. (after I get a signed contract then I will do the engineer) That being said I was just wanting some opinions form ya'll since the HO threw me the curve of headroom. 
I like what Mac said as far as still using the tripled 2x12's. Until I can find something better that is what I will turn in when I get a signed contract. Just want to get all of my ducks in a row before I go to other people. 

_ Originally Posted by *neolitic* 

What I can't understand, is not being willing
to do the research to get to that point.

What do you mean by that? What makes you think I'm not studying this over? I thought I'd start here. It'll be a while before I start this job so there is plenty of time for "research". Two heads are better than one.
_


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## neolitic (Apr 20, 2006)

woodbutchr said:


> Well I don't have an engineer in my pocket for whenever I need one so that is out. (after I get a signed contract then I will do the engineer) That being said I was just wanting some opinions form ya'll since the HO threw me the curve of headroom.
> I like what Mac said as far as still using the tripled 2x12's. Until I can find something better that is what I will turn in when I get a signed contract. Just want to get all of my ducks in a row before I go to other people.
> 
> _ Originally Posted by *neolitic*
> ...


Good on ya!:thumbsup:
It just never ceases to amaze me how many 
guys come here and ask a question that
an easy Google search would have answered
with authority.
Didn't say you weren't gonna follow up,
I'm sure you have those beam tables 
book marked now.
Hasn't been all that long since a guy had
to get to the library or architectural
bookstore for information that you can 
find now in a couple of minutes....
with a beer at your elbow!:clap::clap:


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## woodbutchr (Jul 31, 2007)

Oh yeah, I've had beam tables on record forever, just never knew the strength of a 6" x 6" as a beam? Everything I got is 2x stuff.
As far as the google search, don't believe everything you read on the internet! As far as that goes, don't believe everything you read here at CT!
(not pointing to nobody in particular!)
I just figured if I had a plan that is structuraly sound it may be a little cheaper if all the engineer has to do is say "that looks good" instead of re-designing it.


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## novicepro (Feb 29, 2008)

I was building a carport/deck and here's what I learened.
You can't use posts as beams- there's a reason you wont find them in the span chart. Just look at it this way. Leave your 6x6 post lying on uneven ground, come back the next day it's probably warped- that's without any loads!


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## Jason Whipple (Dec 22, 2007)

novicepro said:


> I was building a carport/deck and here's what I learened.
> You can't use posts as beams- there's a reason you wont find them in the span chart. Just look at it this way. Leave your 6x6 post lying on uneven ground, come back the next day it's probably warped- that's without any loads!


 Shhhh! Don't tell that to the 8 x 8 main beam in my basement! It's been hangin' around for about 120 years now. (I did have to give it a lift when I bought it 6 years ago)


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## woodbutchr (Jul 31, 2007)

I have decided that there will be NO 6" x 6" beams! I'll just have to tell the HO to stick to drivin' trucks.


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## neolitic (Apr 20, 2006)

Jason W said:


> Shhhh! Don't tell that to the 8 x 8 main beam in my basement! It's been hangin' around for about 120 years now. (I did have to give it a lift when I bought it 6 years ago)


Yup, they did sag and they were sawn
for their purpose.
Like I said way back there some where,
the 6X6 you get now comes out of the
center of the tree (probably only a 10"Ø log).
only the outer ¼ on each side has proper
grain orientation (at best.)


"As far as the google search, don't believe everything you read on the internet! As far as that goes, don't believe everything you read here at CT!"

You missed the word authority.
You can get information from the 
APA,AWC,AFC.....definitive authorities,
as well as directly from the manufacturers,
code authorities, etc.
Maybe just as good for sources as strangers
who may or may not know or care.


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## woodbutchr (Jul 31, 2007)

neolitic said:


> You missed the word authority.


You're right, my bad. :bangin:


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## Aframe (Mar 24, 2008)

Steel beams are not that expensive, would drag in an engineers stamp though.
This way you can find out how important headroom is to customer 

not to nit pick, water = 8+ lbs/gal. 
Jason where can we get the light weight water you have.


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