[mlowrie]

I'm finishing up plans for a two level deck - the upper a 16'x20' two-beam ledgered to the house, and the lower a 16'x16' low elevation freestanding deck with a set of stairs joining the two.

I'm only planning on building the lower deck this year and the upper deck next year but I want to ensure that the lower deck is built properly to support the stairs between the two. Not sure yet if I'll get a permit for the lower deck as it isn't necessary but the upper will for sure.

Some info regarding the lower deck:

• Height of decking will be <=2'
• A couple of steps around the perimeter to get to the yard (not shown)
• Probably 2x10 construction. Blocking not yet shown
• No bracing added yet
• Potential room for beams if necessary
• The unframed area behind the hot tub will be a removable section for hot tub servicing
• Composite decking at 45 with a 2 board picture frame. Upper deck shows the framing/blocking that will be copied to the lower deck

I have a couple of questions and hopefully someone can point me in the right direction:

1. Is the double joist framing around the hot tub sufficient or is there a better way? I plan on making all outer joists double as well.
2. What is the best way to frame to support the stairs? Only three joists are shown but not sure if this should be beefed up.
3. I've seen low elevation decks with beams and without. My preference is to use beams but would this deck be better built without (ie frame it so it doesn't require beams)? I see using three beams - one on either side of the hot tub and one ~2' from the house

Would like to hear what some of the experienced guys would do with this design.

Thanks in advance!
Mike

 

[jlhaslip]

Consider turning the joists for the lower deck 90 degrees.
I'm thinking the turned layout will be easier to support that small section of deck on the outside of the hot tub.
Balancing that small section on a single beam is not a good idea, in my opinion.
That section will require a pair of piles regardless of the joist direction.
The beam on the right hand side would need to support the 45 degree knock off corner, so plan on building the beam to that shape.

 

[Gary in WA]

Basement window requires safety glazing, composite at a 45* requires framing 12" on-center, free-standing lower one may also require tension rods/brackets for shear, pp23- I think.., any post within 5' of house requires footing same depth as house foundation to reach undisturbed soil, there is a max. stair stringer (and meat left over after notching) length when cutting an "open" vs. "closed" tread/riser, may need more than 4 stringers, all guard/hand rail posts require special detail at framing attachment and stair posts per Guide; http://www.awc.org/Publications/DCA/DCA6/DCA6-09.pdf

Gary

 

[mlowrie]

Consider turning the joists for the lower deck 90 degrees.
I'm thinking the turned layout will be easier to support that small section of deck on the outside of the hot tub.

I thought about rotating it at one point but never really went through with it but thinking about it now it makes much more sense. I had the same thoughts on the single beam and the small section and I didn't really want to put two posts there so this may be the best option.

I'll rotate the design and check out the result and post back.

 

[mlowrie]

Basement window requires safety glazing, composite at a 45* requires framing 12" on-center, free-standing lower one may also require tension rods/brackets for shear, pp23- I think.., any post within 5' of house requires footing same depth as house foundation to reach undisturbed soil, there is a max. stair stringer (and meat left over after notching) length when cutting an "open" vs. "closed" tread/riser, may need more than 4 stringers, all guard/hand rail posts require special detail at framing attachment and stair posts per Guide; http://www.awc.org/Publications/DCA/DCA6/DCA6-09.pdf

Gary

Gary,

I'm pretty sure that window doesn't have glazing so thanks for reminding me about that.

The deck is designed with 12" O.C joists and have yet to add in all the extras for supporting a freestanding deck but I'll get those in once the general framing design is complete.

Footings will be per code for this area (24"x24"x6" with 10" piers to house at depth of 18" or to depth house footing).

Stringers will be 2x12" to maintain the minimum 5" and probably a closed design but that'll be part of the upper deck design and permit so I'll be getting the requirements from the inspector before that is built.

I've read the DCA guide a number of time already. Lots of good info. I've based a few things from the 2012 version... is there a reason you linked to the 09 version? Not all jurisdictions have updated to latest building code but doesn't the 2012 version have more updated design requirements based on more recent building codes?

Anyway, thanks for the info.

 

[Gary in WA]

Yes, I gave you the choice as some are still under the older one, rather than linking the older one (or newer one) alone and not be applicable. You've done some research, good. Some good ledger flashing you may have seen already; Detail 8; http://www.mtcc1170.com/images/BCRainScreen.pdf though you may not have a rainscreen system, but metals would be same.

Gary

 

[mlowrie]

Gary,

Yes, I try to find out as much info as I can on anything I don't normally deal with to make sure it is done correctly - or better if possible.

The nice thing about the upper deck is that I am also replacing my siding so I can install the rainscreen from a clean slate. I actually followed a lot of stuff in that BC Rainscreen document when I re-did the exterior and all the windows but I used the Dupont Flexwrap for the sills instead of the peel and stick - wonderful stuff.

Anyway, I did a quick mock up of the lower deck with the joists rotated which will work much better. Not sure why I didn't think of doing this before. The nice thing is that the stairs will land on top of a beam which should minimize any flexing around it and provide a solid connection.

I'll finish up the details here in the next or so and get everything up to code.

One thing I did notice is that the beam is pretty damn close to the top of the pier. I don't know if I can get the pier<->post and post<->beam hardware on with that short of a distance. The lower deck is still only shown with 2x8 not the 2x10 I plan on updating it to. sigh...

 

[jlhaslip]

I would continue the outer beam across the face of the 45 degree corner.
Those joists are cantilevered too far off the middle beam.

 

[mlowrie]

I would continue the outer beam across the face of the 45 degree corner.
Those joists are cantilevered too far off the middle beam.

What?!?! It can't handle a 3'cantilever! :smile: I just threw it in quickly and wasn't the final design. After thinking about it I have two questions:

1. If using the double rim joists around the 45 degree corner, is it necessary to have a beam on that end or can I use a number of posts under the double rim? The 45 degree is only 5'7" long so the span should be well within limits.

2. On the far end of the deck, I won't be able to support the beam with a post as the footing will interfere with the footing from the upper deck. Can this lower deck be supported by the post from the upper deck? I can adjust the post out so that it can be sandwiched by the lower deck. This method is till allowed for low elevation decks isn't it?

 

[jlhaslip]

Increase the size of the footers and have two piers coming off the same footer is how I would think about doing it.
The trouble with having the piles/piers come up to carry the double rim is accuracy of placement. Also, the beam moving back a foot or so is a visual thing.

 

[AndyGump]

Please consider having a professional design this for you to what ever your local code requires.

Andy.

 

[mlowrie]

Please consider having a professional design this for you to what ever your local code requires.

Andy.

I did consider it but won't be. My building inspector will let me know if the design is up to code or not.

Mike

 

[AndyGump]

I guess I can't blame you for going that route since you have a couple guys on the forum designing it for you for free.

Good luck.

Andy.

 

[mlowrie]

I guess I can't blame you for going that route since you have a couple guys on the forum designing it for you for free.

Good luck.

Andy.

That's for being so supportive - and yes, I'm glad people are designing my entire deck for me for free.

Mike

 

[Gary in WA]

Well... that is totally out of character for Andy... maybe he had a bad day. I was actually showing you tips from the SAME design prescriptive Code Guide that designers use, or hope they use...

Gary