How to finish deck stairs on a concrete slab?

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Posted by: from New Hamburg
5/26/2015 at 10:06:55 PM

I recently built a deck off our main floor over our walkout basement. I build stairs down to a concrete slab and I'm finding the railing to be pretty wobbly. Is there a way I can beef them up without pouring footings for the bottom posts?

They currently are attached to the bottom outside stringers with lag screws and just rest on the slab. Can I attach angle brackets to the posts and concrete? Should I brace the stairs in some way? I have two posts mid span that are anchored into the slab but that has only stopped the bounce.

Any help would be appreciated.

Thank you,


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Erik in New Hamburg
Date/Time5/26/2015 at 10:49:35 PM

Here is a Picture without the railing.

How to finish deck stairs on a concrete slab?
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Date/Time5/28/2015 at 10:24:37 PM

Hi Erik,

There are a couple of things you can do.

The first is to install post bases into the concrete where the railing posts land. This will help stabilise the post and the stringer.

The second is to put on the risers. That will stabilize the stringers by triangulating them and fix the "no gaps larger than 4" rule. You can usually use 1 X 6 fence boards for that.

Good luck with it!

Jim Kuzma

Kettleby Handyman

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James from Deckster Decks in Scarborough
Date/Time2/11/2016 at 2:01:40 PM

First. Close the risers. As per building code, risers should be at least 1" thick. Either 5/4 deck boards or 2x material is adequate.

Second. The back of the riser is going to flex as pressure is put on the railing. Installing bracing across the back of the stringers will prevent this.

Your maximum span on posts for railings is 6'. I would put bracing wherever you have a post and that will firm everything up.

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