[cornerspeed92]

I am building deck,actually more of a porch extension.I have built 2 decks,and 2 patio covers,so i know what i am doing.My question is this,this will be a free standing structure,unlike to other decks i have nothing to tie to,as this is a mobile home.This structure will be 4' above the ground,im digging my footings 18",and i know this will be secure.Will there be any feeling of wobbliness when the people are on the deck/porch.This is not for me it is for someone that i am doing work for.The extension will be accessible from there existing 4x4 porch/landing that they use to enter their house.
The top of the drawing is the front view,and the bottom one is the top view without the 2x6 decking on.

[shank0668]

I would think going 18" down will be sufficient, and a good idea. I was looking at fixing someones, but theirs just sits on the ground. I would probably overdo things and add cross bracing to the pillars, or whatever you want to call them. that way there would be almost 0 chance it would move.

[shank0668]

And I take it you are bolting the top frame to the 4x4's

[gml1998]

Diagonal cross bracing and you should be good.

[cornerspeed92]

Thanks,yes.I am using the 2-2x6's on front and back to put my joist hangers on.I thought about running 2x6 cross braces as well.

[shank0668]

Originally Posted by cornerspeed92

Thanks,yes.I am using the 2-2x6's on front and back to put my joist hangers on.I thought about running 2x6 cross braces as well.

I would think you would be good to go. Nice thing about the cross bracing... you could always do it afterward. lol.

[cornerspeed92]

Exactly

[ssrs2lt]

In the east we've gotta go deeper, 18 wouldn't cut it. Bolts and cross rails hold it steady. Good luck

[Mr_Draco]

Originally Posted by ssrs2lt

In the east we've gotta go deeper, 18 wouldn't cut it. Bolts and cross rails hold it steady. Good luck

Yea. We have to go a minimum 6" below the frost line, which varies from county to county.

You didn't say what you are using for supports, but for 4' high I would use minimum 6x6's for strength of rigidity also in your diagram you are missing the cross joist's which will also aid in this.

Have you or the owner given any thought to how the decking will be laid? The current way you have the joist laid out, the decking will have to be laid out length wise instead of width wise. Nothing wrong with this but depending on the direction of travel and the look compared to the existing deck you may need to change how you are doing the joist so the decking can be laid width wise.

[cornerspeed92]

Yeah,i was going 18"deep with with the concrete with the long post saddles,which would be like 12"in concrete and 4x4"s.In the sketch i was just trying to show the basic of what i was doing.I am laying the 2x6's long ways,it will look better then the other way.

[67RS2010SS]

In the north east we go 42" for our piers. You will need diagonal bracing on your posts and it would be a good idea to install some diagonal bracing under your floor joists. You can run your rim joist all the way around your deck and notch the post so it actually sits on the post. As someone else noted 6x6 posts would be much better. Sandwiching the posts the way it is drawn in your sketch is not really an acceptable practice and you are relying on a mechanical fastener to support the load. Hope this helps

[NH 2012 SS/RS]

Yes I own a remodeling company.
Telling him what we do in our areas of the country is useless and unnecessary. He lives in earthquake country. You do and will have seismic codes and issues to deal with. Make sure you get a PERMIT and you should be fine. The code officials will help with what is needed to make sure it is safe

Good luck

[Midlife conVert]

I don't know if insect damage would stop you but for a trailer whose life is not infinite I would bury the post.. That would stop a lot of wobbling. I would go down at least two feet and pack the post in good. That is saying against code for some reason.
And
IMHO 2 x 6 is very undersized for joists.

[cornerspeed92]

Originally Posted by 67RS2010SS

In the north east we go 42" for our piers. You will need diagonal bracing on your posts and it would be a good idea to install some diagonal bracing under your floor joists. You can run your rim joist all the way around your deck and notch the post so it actually sits on the post. As someone else noted 6x6 posts would be much better. Sandwiching the posts the way it is drawn in your sketch is not really an acceptable practice and you are relying on a mechanical fastener to support the load. Hope this helps

Good God 42" thats half way to my grave ,yeah, 6x6 would be the bomb,but would look way out of place for this application.

Originally Posted by NH 2012 SS/RS

Yes I own a remodeling company.
Telling him what we do in our areas of the country is useless and unnecessary. He lives in earthquake country. You do and will have seismic codes and issues to deal with. Make sure you get a PERMIT and you should be fine. The code officials will help with what is needed to make sure it is safe

Good luck

Thanks

Originally Posted by Midlife conVert

I don't know if insect damage would stop you but for a trailer whose life is not infinite I would bury the post.. That would stop a lot of wobbling. I would go down at least two feet and pack the post in good. That is saying against code for some reason.
And
IMHO 2 x 6 is very undersized for joists.

I like this as well,but i have been doing a lot of fence repair at the condo place i work at,and even though they used pressure treated 4x4's,these are just rotting away,so i want to keep out of the ground.
Thanks everybody for your info.This place(C5)is a great place for help,and info