help with deck/patio design

[mound]

So I plan to make a deck off the front of my house. Technically it will be a "patio" as it's just under 18" off the ground and won't have railings or built-in seating.

Total size is 24'x6'

I started my Sketchup drawings from the top-down -  the "picture framed" deck pattern I want to see, then the joists and blocking to support that. 

What's the proper design for the layout of the posts and beams below it? I could go totally free standing or the rear-most ledger board could be properly flashed and bolted to the house. 

Would you do a series of short beams that extend out perpendicular to the house and several footings, or maybe 4 footings across the width out toward the front of the deck with a long beam running parallel to the house?

edit: I'm thinking just one long beam parallel to the house like the last image below. 

thanks!

[MstrCarpenter]

Both. To start with, you don't need to complicate the framing at the 6' ends. The "picture frame" decking on the ends are already perpendicular to the joists. The joists can't span 24' so four 6' beams cut the span to less than 8'. Put a ribbon joist on the outboard ends to keep everything square which creates a support grid to build the deck frame on. This will be useful if you nail the ledger board, first common joist, and blocking together as an assembly, then attach it to the house. I would consider doing the same on the outboard side. Just don't forget to leave space at the ends for the short diagonals. I've done a few low decks with full length steps. It makes the yard more inviting, and provides ample informal seating. At 18" there'll be 3 risers. You can decide if you want guard rails on the ends of the deck, but I highly recommend (at the very least) handrails at the ends of the stairs. You can't tell us that you'll never have guests that would feel uncomfortable traversing the stairs without something to hold onto.

[Snipe Hunter]

18", So 3 risers. 3 risers require a hand rail and balusters. Me personally, I wouldn't run the decking boards perpendicular to the house. That's an awful lot of work, beams, footers, columns and money. The bottom picture does not provide support for the joists.

That being said, I would make it free standing with 2 beams running the length of the deck. No ledger board. You can still do a picture frame by adding a spaced rim joist on the ends. Attaching to the house is fine but I'd rather not have to do it, rather not have to modify siding and install flashing etc. This is always a source for rot and termites in your under-structure if not done correctly and if you ever want to change things, you don't have to re-side the house.

[mound]

Thanks to both of you.

3 risers not 2?

So this is going to replace a smaller (and crumbling) cinderblock/concrete step (see drawing below) which is 18" high but only has one step.  Can't I more or less do the same ("2 risers") with the deck? I'm not sure any kind of hand railing would make sense for what's currently there, and this should just replace that space. No?

Interesting idea about the full length step.. I think LOML planned to put a garden bed in front of the majority of its length.  

Agreed my drawing (one long beam) doesn't support the joists. Seems obvious to my eyes now! Sometimes I lose perspective of "scale" when playing in Sketchup.. 24' is long!  I'll do 4 beams running orthogonal to the house. 

I've also been leaning toward the free-standing, rather than messing with existing siding and trying to bolt on a ledger. That just means 4 more holes to dig. I guess it's a trade off.

The addition of any sort of railing makes it a "deck" instead of a "patio" in so far as town code, which then requires a permit and inspection (which is fine too, but that just complicates things)

Illustration of current concrete patio:

[joe1086]

Your current steps are too tall. Check your local codes but usually a rise of 7 3/4" or less.

[joe1086]

And bring your check book AND credit cards when you go to purchase the lumber. I was in HD yesterday and a PT 2x2x8 was almost $10 or $11 each.....

[mound]

And bring your check book AND credit cards when you go to purchase the lumber. I was in HD yesterday and a PT 2x2x8 was almost $10 or $11 each.....

Yah its crazy.. I have a stack of good material that's been looking for a home, so that will help.

[mound]

Your current steps are too tall. Check your local codes but usually a rise of 7 3/4" or less.

Interesting. Most every house in the neighborhood is the same. 

For 3 risers they'd have to be 6" - that seems like it would feel awkward..  I'll check the codes.

[Snipe Hunter]

Your current steps are too tall. Check your local codes but usually a rise of 7 3/4" or less.

+1
This is code and riser height can't deviate more than 3/8" from each other.

[atgcpaul]

3 risers not 2?

Your 3rd riser could be your band joist.

(Not to scale)