A ladder for what purpose? I'm not sure that something like that complies with building code.

Even if it's safe (and I have my doubts about that), I think you're going to make a mess of that wall pretty quickly.

I wonder if they aren't custom iron pieces installed on something like these brackets for floating shelves, bolted to the studs inside the wall with bolts strong enough to carry the weight of a person. I'm not suggesting that these would be strong enough, just that may be how they had them fabricated:

Maybe look for something like these? climbing rungs

From osha handbook:

https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.23

eta: I tried some other search terms and found someone else searching and this answer was provided - not sure if any of the links are still good:

You are going to have to have a metal shop fabricate it out of bar stock
and plate steel welded to the bent bar stock, to form the rungs. Also,
you need to know what size of bolt and the length, for a certain weight
that it will hold a person of say 250 to 300 lbs.

That means you need to talk to a engineer that can design the fixture
and draw up drawings on CAD, so that you can give to the fabrication
shop to make the rung fixtures with the proper gauge steel and plate,
and proper sized holes.

Well lookie here, found you a company that manufacturers the ladders, http://flextechdampers.com/osha.html Another company
http://www.fsindustries.com/more_inf..._ladders.shtml
OSHA requirements on fixed in place ladders http://www.osha.gov/pls/oshaweb/owad...ARDS&p_id=9719     

Here's the chat room: https://www.diychatroom.com/f19/where-get-rungs-individual-rung-ladder-181316/

That shouldn't even be there... Someone was out of their mind to chose that location to have that there.

That said and before you plan on using this... and find out what they rated for, what weight and make sure the rungs properly installed...

I would also suggest you add a few full height grab bars on the sides, that will help a lot because the wrong step or loss of balance and someone will have a long and painful dive down both stairs specially if you have kids in the house. Not to mention looking at the other staircase I'm not sure if that stairway would meet any local code compliance in the States.

Good luck

I highly recommend you forgo this design and buy a fixed uncaged ladder! A fixed ladder is your best bet for both safety and resale.

I cannot in good faith recommend this setup for anyone over 100lbs. (I think that's even pushing it. Those look like towel bars!)

The setup in the pic wouldn't meet code in the US. It's a Japanese ad for an architectural design firm.

I know the simplicity appeals to you, but please consider this type of ladder:

https://www.globalindustrial.com/p/janitorial-maintenance/ladders/fixed-access/standard-uncaged-fixed-access-ladder-gray-9?infoParam.campaignId=T9F&gclid=EAIaIQobChMIkZ6SkY2Z5AIVmIjICh34WgRyEAYYBSABEgJouvD_BwE

I don't like that the ladder is right by the stairs. Crazy idea. Sounds like an AIRNB idea.

Or a Tiny House setup.

That was intended for a house with concrete wall, not the regular american dry wall.

https://www.etsy.com/listing/824440277/monkey-bars-home-gym-jungle-gym-crossfit?ref=listing-free-shipping-bundle-1

https://shelfology.com/accessories/randle-indoor-monkey-bars/