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flyultralite 04-21-2007 09:54 AM

Deck support beam
 
Hi everyone, I just finished writting a lengthly thread then my computer froze. I'll make this quick...I'm building a 32' x 12' deck on the side of my house this summer. What size joists are recommended, 2x8 12" o/c or 2x10 16" o/c?? For a deck this size what kind of support beam is recommended? I'm thinking of using the "Sandwich Beam" technique (2 2x10's sandwiching my three 6x6 posts) Is that sufficient enough or should I build something more "beefy" and actually have the beam resting ontop of the posts?

Also, what is the maximum overhang I can go over the support beam??

Is 3 6x6 posts too little, should I really be putting 4 up?

When I dig my holes for the SonoTubes I'll be using my fathers Back-Hoe. It doesn't make the smallest holes but its quick and easy. Once my SonoTubes are in place, would it be best to back fill the holes with what I just took out, or would filling it with gravel be better? I have easy access to free gravel so there's no additional costs, I just want whats best.

Any tips or suggestions would be greatly appreciated. Thank you in advance.

Bryan D

AtlanticWBConst. 04-21-2007 04:29 PM

Quote:

Originally Posted by flyultralite (Post 41817)
Hi everyone, I just finished writting a lengthly thread then my computer froze. I'll make this quick...I'm building a 32' x 12' deck on the side of my house this summer. What size joists are recommended, 2x8 12" o/c or 2x10 16" o/c?? For a deck this size what kind of support beam is recommended? I'm thinking of using the "Sandwich Beam" technique (2 2x10's sandwiching my three 6x6 posts) Is that sufficient enough or should I build something more "beefy" and actually have the beam resting ontop of the posts?

Bryan,
Don't you hate that? UGH...

Joist sizes/widths are dependant on the span. Generally, you want to start at 2x10" at 16" OC, and go up, based on the span and the loads that you plan on having on the deck.
Support beams should be tripled...starting with 2x12". I always recommend either 6x6 or 4x6 posts. I would also definitely recommend that you place your beam on top of the posts. Sandwiching the post puts all the weight load on the bolts. (Use simpson stong ties at all connection points)

Quote:

Originally Posted by flyultralite (Post 41817)
Also, what is the maximum overhang I can go over the support beam??

approx. 24"

Quote:

Originally Posted by flyultralite (Post 41817)
Is 3 6x6 posts too little, should I really be putting 4 up?

Definitely more than 3....
The actual number of posts is really determined by the design of the deck, weight loads, etc...

Quote:

Originally Posted by flyultralite (Post 41817)
When I dig my holes for the SonoTubes I'll be using my fathers Back-Hoe. It doesn't make the smallest holes but its quick and easy. Once my SonoTubes are in place, would it be best to back fill the holes with what I just took out, or would filling it with gravel be better? I have easy access to free gravel so there's no additional costs, I just want whats best.

Gravel on the bottom. Backfill with the previously removed soil....

These are just my initial recommendations, based on loose info. you listed. If you can do a detailed layout, there is more that can be figured out. Additionally, there are posters on here that I consider 'deck geniuses', compared to my suggestions.... (I build decks, but I don't build ONLY decks for a living. There are some members here that do)

concretemasonry 04-21-2007 05:47 PM

How are you going to support the deck near the house? Are you going to go with a free-standing deck or are you going to take a chance on a treated ledger flashed and through-bolting the rim joist? Check on whether your local code allows a ledger.

with a 32 x 12 deck, you may want to consider some diagonal bracing for stability. You probably will not be able to count on the Sonotubes and posts.

You code submittal/approval will probably catch these points, but it is good to be prepared.

flyultralite 04-21-2007 07:52 PM

Well the thing is, I literally live in the bush. I own one of only two houses on a single lake in Northern Ontario. I live on one side and the other house lives on the other side. We live in whats called an unorganized township. Therefore we don't have codes and permits to obid by.

AtlanticWBConst. 04-21-2007 08:18 PM

Quote:

Originally Posted by flyultralite (Post 41850)
Well the thing is, I literally live in the bush. I own one of only two houses on a single lake in Northern Ontario. I live on one side and the other house lives on the other side. We live in whats called an unorganized township. Therefore we don't have codes and permits to obid by.

Wow...sounds peaceful and serene...:)

So you don't have any code enforcement. Well, you can still use the ICC as a guide to doing your deck right and safe....

Darylh 04-22-2007 11:54 AM

4 Attachment(s)
If I was building a deck that size and I was not building any structures on it I would build it in this manner:
At least 2x10 16" o/c
3- 2x10 laminated beams on TOP of my 6x6 posts (4 posts) run rolled roofing strips on top of your beams before installing joists.
24" x 24" x 6" footings at frost level ( see pic)
2x10 carrige bolted through rim joist on house flashed and counter flashed ( see pic)
Cantleever 16"
The below pic showes how I support the bottom of the sonotube.
I also use 6x6 post saddles in the concrete
You can also do this without having to use wooden posts but your saddles have to be right on.
Hopefully I have not forgotten anything.

robertcdf 04-22-2007 08:08 PM

How high is your deck going to be? I feel more comfortable putting in 1 more post on taller deck than ground level decks.

So here is my opinion on a ground level deck (up to about 3' high)

2x10 ledger flashed all around OR use a spacer system like deck2wall

Ledger should be attached with 3 3/8" bolts @ 16" O.C.

Joists should be MIN 2x10 16" O.C. with midspan blocking in the framing. It would be a little better if you went to 12" O.C.

Beam should be MIN 2 2x12's with 4x6 or 6x6 posts every 8' and if it is a taller deck add 1 more support post.

2' Cantilever over the beam would be just fine and if you did do 2' then 16" O.C. joists would be fine (since the joists are now only spanning 10')

your 2 end piers should be min 4' deep and 12" diameter ALL the way down and filled with concrete with the post in a saddle. Your CENTER piers should be a min 4' deep and 18" diameter.

If you use ACQ treated wood then you should use stainless steel for ALL nails, screws, hardware and such. Also keep in mind DONT use screws for deck hardware. Screws dont have shear strength they will snap instead of bending a little under load.

If you have any other questions feel free to ask...

Also it may not be a bad idea to contact the closest building department and see what kind of specs they require for decks. Even if you are not in that jursdiction they will know more about the local enviroment and needs.

AtlanticWBConst. 04-22-2007 08:28 PM

Quote:

Originally Posted by robertcdf (Post 41944)
...Also it may not be a bad idea to contact the closest building department and see what kind of specs they require for decks. Even if you are not in that jursdiction they will know more about the local enviroment and needs.

....they will know more about the local enviroment and needs....

Good point Robert....

crecore 04-28-2007 08:00 AM

thats one hell of a deck footing daryl! I personally prefer more posts and less beam on cold climate clay soil where I live in northern NY... this seems to float better through the heaving of the seasons and remain flat.

Darylh 04-28-2007 08:57 AM

Quote:

Originally Posted by crecore (Post 42653)
thats one hell of a deck footing daryl! I personally prefer more posts and less beam on cold climate clay soil where I live in northern NY... this seems to float better through the heaving of the seasons and remain flat.

Yah I hear yah, I tend to over build. You could step the footing down to 4" thick and have a real nice stong deck founation. We have clay up here to also known as "HardPan" which is nice to build on since its practicaly a foundation on its own so 4" is sufficent. I look at decks as a extention of the house and who knows whats going to happen in the future and also if your digging holes and pouring concrete one might as well go the the extra mile.


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