Small raised deck/stairs concrete slab

Old 03-16-14, 12:15 AM
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Question Small raised deck/stairs concrete slab

My father recently had a stroke so I need to add a wheelchair elevator to my parent's mobile home. I've already found one and thats all ready to go. However, the stairs/deck that the elevator will be adjacent to are old and not very stable. I am thinking of building a new one while I'm at it. I've confirmed that as long as I keep the deck under 16 square feet, and the elevator doesn't require new electrical outlets, that this can be done without a permit.

I've got lots of great deck plans, definitely its within my skill range and I've got the tools. But there's one aspect of this I think will be challenging. The door to their mobile home is off of their covered driveway - the whole thing is on a concrete slab. The door is 37" above the ground. All of the instructions for building decks I can find involve embedding the posts well below the ground. I don't think it would make sense to put massive holes in the concrete for this.

I could attach the posts to the concrete with anchors, using spacers to keep the pressure treated wood off the ground. In fact I guess this is necessary to follow code. But I'd like to keep the stringers off the ground as well. What I thought I'd do is anchor a 2x8 platform onto the ground (pressure treated 2x8s laying flat). This will allow me to attach and build up on this platform.

Now my concern is with the posts - especially the 2 posts at the end of the stair rail. It seems this post will be very weak since it will only be held at the bottom. At least the deck posts will have the joists in the middle giving them a fairly rigid structure.

Here's a series of 3d drawings to show the basic design.

This is the platform that will be anchored securely to the concrete slab. I'd put tar paper under them as well.

This shows the posts. They'll be attached with screws and angle brackets.

This shows the frame, including a 2x4 cleat on the front to support the stringers.

This shows the stringers. I've gone one more than needed but like I said I want this to be rock solid.

This shows the finished deck/stairs. I'll use composite decking for the floor and treads and painted plywood for the risers. It doesn't include the railings-- I plan to use off the shelf deck railing kits for the stairs and back side of the deck. The side facing the elevator will have a gate, and of course the other side faces the door.

I'm mostly worried about the bottom rails and whether they'll be strong enough or not. But any overall suggestions are welcome as well. The goal is to make this very sturdy, attractive and long lasting. There are pre-manufactured stairs but so far it seems they're all the wrong height. I may look at that again though you'd think this is standard. But I wouldn't mind doing this myself if it means building something stronger and more attractive.
Old 03-16-14, 02:15 AM
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Okay I think I know what I can do. For the bottom posts I can build a small box around them, and fill the box with concrete. The box can go as high as the 2nd stair, and extend under the first stair up to the first inner stringer. I can cover the exposed box with painted plywood to have it fit nicely into the design, and it should give enough rigidity.
Old 03-16-14, 04:33 AM
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None of your attachments work.
Why not ramps instead of an elevator?

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