Exterior staircase landing retrofit that incorporates storage

The landing for my parents' exterior stairway rotted out and we're trying to retrofit a new landing without replacing the whole stair. They also want to have some covered storage under the landing for lawn equipment. It's not a very Permie project but I like the design challenge of function stacking a stair landing with covered storage. I've attached some pictures of the existing state of the stairway. Here is a proposed design I came up with this morning.



It will take quite a few structural fasteners that I'm not super pleased with but I probably won't be building it and want to make it a fairly easy build. If you have any tips or suggestions I would appreciate it.

Looking sturdy so far, but I suggest one easy idea.  From building a few chicken tractors over some years, I do agree with one of the tractor gospels:  always hit untreated lumber with a single coat of basic flat white paint.... a healthier option for your soil and lasts about as well as treated wood. Best of luck on your project.  

some ideas;
- Untreated timber particularly pine will rot even with paint.
- The diagonal or knee braces on the ends should extend down to the base of the column for max. strength against movement
- roof could extend past the beams 2 inches or so for a gutter
- roof battens I would use 3 x 11/2 inch in Australia
- cross bracing [ galvanised strap ] under deck nailed both ways to the floor / decking  joist will prevent twisting and collapse
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I'd try to make the railing posts be the same wood as the support posts.  They'll be much beefier that way.  I also don't know if you need that much pitch.  If it keeps people from bumping their heads, going a bit flatter might work since you aren't dealing with snow load.

Thanks for the responses!

John C Daley wrote:
- The diagonal or knee braces on the ends should extend down to the base of the column for max. strength against movement

I'm trying to keep the ends somewhat open for accessibility. Ideally, it would be best if it was fully cross-braced. Do you know of any rules for knee brace placement? I typically locate them about 1/4 of the post height down from the post beam connection.    

John C Daley wrote:
- roof could extend past the beams 2 inches or so for a gutter

Sounds good. If the parents go with a barn style door it won't interfere with the operation.

Mike Haasl wrote:
I'd try to make the railing posts be the same wood as the support posts.  They'll be much beefier that way.

That's a good idea especially for the new post. For the one sistered on to the car port post the car port roof may interfere.  

I'm a little concerned that you may end up with a glory hole below the landing on top of the roof. Stuff could fall down and not be retrievable, or unwanted visitors might make a nest in there. I'd make sure you can get under there with a broom if you need to.

Thoughts...maybe it could be a habitat for some wild life that you would want...bats? birds? But then maybe the decking would be waterproof and the underroof redundant. Just wondering.

Nancy Reading wrote:I'm a little concerned that you may end up with a glory hole below the landing on top of the roof. Stuff could fall down and not be retrievable, or unwanted visitors might make a nest in there. I'd make sure you can get under there with a broom if you need to.

Thoughts...maybe it could be a habitat for some wild life that you would want...bats? birds? But then maybe the decking would be waterproof and the underroof redundant. Just wondering.

You're right it could become a leaf/debris trap. I could leave a little gap between the roof and ledger board and then attach piece of angle flashing or drip edge on the ledger board just below the joists to cover the gap. See picture attached. That would allow me to use a leaf blower to clear the roof.

I will admit I don't have a clear idea of all the bits involved here, so I will just say what the Fire Department said to a local organization:
"We do not permit any storage under stairs due to the fire hazard."

I'm a firm believer in stacking functions, and if it was only garden tools like rakes, I wouldn't be concerned. However, if the mower requires gas, or the type of batteries that occasionally decide to burn, at the least, I would be lining the underside of the landing with metal backed with fireproof material.  Similarly, I'd be sure there was good ventilation so that fumes couldn't build up. And *please* make sure they don't leave greasy rags under there. That's how a friend of mine tried to burn his shed down...

The stair landing needs some finishing details but is functional. So we can all have some closure and for your (possible) enjoyment here is the build video:



Thanks for all of your comments and advice.