That’s a good question. The type of guy I was referring to here would be all about custom building the entire thing - stringers, risers, treads, tailings, balusters, trim, etc. As far as I know, stairs are generally a custom thing since they have A LOT of code requirements and every space has different dimensions, unless you’re building track housing, etc.
There are a good deal of old homes that are worth good money and have owners with the means to replace or repair their old, squeaky stairs. Or renovations going on in old homes that require new stairs. And any new custom hone is going to need custom stairs.
No idea on liability insurance but I’d imagine similar to other trades. The stairs guy would only be responsible for gathering the space specs and design. They then build the stairs in their workshop and deliver them to the site. Carpenters install them. Then the stairs guy comes back and installs the railing, etc. which can take a lot of custom work (rail fittings, bending rains, etc) and balusters. Real craft stuff there.
By chance I've been consolidating meta-data on old DIY, Craft, et el. TV series and This Old House Season 11 E15 (Concord Barn, 1989) featured an in depth walk through of just such a specialised custom stair case shop that's still very active.
They design and shop build production run and custom stairs, dismantle, ship, and fit or oversee fitting on site.
Seems like a good business: Over 50 Years of Custom Staircase Design and Construction
There are a good deal of old homes that are worth good money and have owners with the means to replace or repair their old, squeaky stairs. Or renovations going on in old homes that require new stairs. And any new custom hone is going to need custom stairs.
No idea on liability insurance but I’d imagine similar to other trades. The stairs guy would only be responsible for gathering the space specs and design. They then build the stairs in their workshop and deliver them to the site. Carpenters install them. Then the stairs guy comes back and installs the railing, etc. which can take a lot of custom work (rail fittings, bending rains, etc) and balusters. Real craft stuff there.