Building and Construction - Post and Beam Layout for large deck

Author

Post and Beam Layout for large deck

exatxer@gmail.com

2007-02-25, 5:25 pm

I am building a 20' by 34' deck. One of the 34' sides will be against
the house. Joists will run with the house.The deck will be 8' off the
ground on 6x6 posts, joists on 12" centers. From What i have
researched, I could use 2x12's with one 3-2x12 beam in the center,
leaving 17' 2x12's on each side.

Or, I could use 2x10's, 2 3-2x10 beams with 2 12ft spans and a 10ft
span.

I am having trouble figuring out how far apart my posts can be aroud
the outside edge of the deck.

Also, any suggestions on going with 2x12's and a long span verses
2x10's and a shorter span. I have drawins I can send.

Thank You,
Jim

Chuck

2007-02-26, 9:25 am

<exatxer@gmail.com> wrote in message
news:1172440743.888524.212080@s48g2000cws.googlegroups.com...
>I am building a 20' by 34' deck. One of the 34' sides will be against
> the house. Joists will run with the house.The deck will be 8' off the
> ground on 6x6 posts, joists on 12" centers. From What i have
> researched, I could use 2x12's with one 3-2x12 beam in the center,
> leaving 17' 2x12's on each side.
>
> Or, I could use 2x10's, 2 3-2x10 beams with 2 12ft spans and a 10ft
> span.
>
> I am having trouble figuring out how far apart my posts can be aroud
> the outside edge of the deck.
>
> Also, any suggestions on going with 2x12's and a long span verses
> 2x10's and a shorter span. I have drawins I can send.
>
> Thank You,
> Jim
>

I will make suggestions for your framing. You really need to have a
structural engineer in your area to give you the appropriate answer to
follow the building codes in your area.
Divide your 34 feet into three spacing's. You will have joists spanning
11.33 feet. This will also be the post spacing. Span a larger beam for 20
feet from the house connection to the support posts. Space your joists at
12 inches on centers to span the 11.33 feet. You need to design the joists
per code for the deck. The live load may be 40 psf, 50 psf or 60 psf you
need to check the values with the building dept. Then you have to include
the dead load. Don't know what kind of deck floor you are going to use.
Flat 2X's, plywood what??? You need to use that dead load also for the
design dead loading. Then all the anchoring systems for the beams, joists,
and post need to be designed. You will also have foundations for each post
and a good connection to the house. If you aren't going to use the house
structure to support the beam loads then you will have to add posts at the
house also. If you do you will need to provide a concrete footing under
those posts also.

Good luck..

CID...

Alan

2007-02-27, 3:25 am

I would have to disagree with the previous post calling for hiring a
structural engineer, except for the fact that the foundation for this
remains unknown. You can calculate much of this yourself, and then
when getting the permit approval, corrections can be made. Use the
span tables for lumber available on-line and then make sure your
choice of lumber exceeds the requirements. For example, if the span
chart says that for your load a 2x10 will span a maximum of 10 feet,
then make the span 8 or 9 feet maximum. Then make sure to use Simpson
Strongtie metal joints everywhere, and soak the framing members with
Jasco preservative before painting or staining. In the long run, rot
will be your biggest problem.

On Feb 25, 1:59 pm, exat...@gmail.com wrote:
> I am building a 20' by 34' deck. One of the 34' sides will be against
> the house. Joists will run with the house.The deck will be 8' off the
> ground on 6x6 posts, joists on 12" centers. From What i have
> researched, I could use 2x12's with one 3-2x12 beam in the center,
> leaving 17' 2x12's on each side.
>
> Or, I could use 2x10's, 2 3-2x10 beams with 2 12ft spans and a 10ft
> span.
>
> I am having trouble figuring out how far apart my posts can be aroud
> the outside edge of the deck.
>
> Also, any suggestions on going with 2x12's and a long span verses
> 2x10's and a shorter span. I have drawins I can send.
>
> Thank You,
> Jim

Chuck

2007-02-27, 3:25 am

"Alan" <atufft@gmail.com> wrote in message
news:1172552429.512818.238830@z35g2000cwz.googlegroups.com...
>I would have to disagree with the previous post calling for hiring a
> structural engineer, except for the fact that the foundation for this
> remains unknown. You can calculate much of this yourself, and then
> when getting the permit approval, corrections can be made. Use the
> span tables for lumber available on-line and then make sure your
> choice of lumber exceeds the requirements. For example, if the span
> chart says that for your load a 2x10 will span a maximum of 10 feet,
> then make the span 8 or 9 feet maximum. Then make sure to use Simpson
> Strongtie metal joints everywhere, and soak the framing members with
> Jasco preservative before painting or staining. In the long run, rot
> will be your biggest problem.
>
>

Sorry, not if getting the permit approval requires that a structural
engineer to provide the design.
The only other way that is described above is by a licensed architect .
Also, how do you know he can do the calculations by himself? Maybe he is
just a home owner that wants to do the work himself.

> On Feb 25, 1:59 pm, exat...@gmail.com wrote:
>
>

longshot

2007-02-27, 9:25 am

> Sorry, not if getting the permit approval requires that a structural
> engineer to provide the design.
> The only other way that is described above is by a licensed architect .
> Also, how do you know he can do the calculations by himself? Maybe he is
> just a home owner that wants to do the work himself.
>
>
most lumberyards or diy stores have free layout programs for decks

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