[clairity]

i probably overstated my point by saying drywall has no shear strength, but we seem to agree that drywall < plaster & lath[0] < plywood in that respect. i'd suggest you've also overstated the strength of drywall as "significant". it's not nothing, but against an earthquake, it's approximately nothing. plywood backing, of course, is the minimum required by code for earthquake resistance.

plaster & lath is harder to work with, but has many superior qualities (re: moisture, sound, heat, malleability) that it makes it worth it in many residential cases (not so much commercial, where reconfiguration is more frequent).

[0]: a lathe is a machine tool

[lazide]

Depending on thickness and stud construction, drywall has higher calculated shear load than lath and plaster -

https://up.codes/s/shear-walls-sheathed-with-other-materials

There are easy to install drywall elements (heavier drywall, or sound deadening backing sheets) that also cut down on noise.

As with all things, ‘it depends’. Lath and plaster isn’t used much anymore because the cost rarely outweighs the benefits.

In non-seismic shear wall usage, it’s allowable to use either.

(Edit: fixed my very persistent autocorrect from lath to lathe - doh, thanks for noticing that)

[bombcar]

Or what you often find in residential construction, lath and plaster under drywall hahahaha (I die now).

[clairity]

that sounds to me like a (bad) renovation. what really sucks is damaged plaster & lath being ripped out and patched with drywall. that's the worst of both worlds, since you don't get the seamless barrier that is plaster or the ease of use of drywall.

[bombcar]

Oh god there's so much bad renovations everywhere. My kitchen is technically an addition so one wall is: paint, drywall, wall paper (4 layers), lath and plaster, exterior cedar shakes, shiplap, and finally studs.

[lazide]

Beautiful. Part of why that happens I think is everyone is afraid to peel a layer off for fear of what they’d see underneath. A lot of contractors try to avoid renovations because it’s a never ending series of pandora’s boxes.

My favorite when checking out a potential house purchase once was a small wet spot in the middle of a wall.

When I pressed on it with my finger - and my finger went right through - into live termites!

That finger press probably saved me $75k and months of headaches.

[bombcar]

Yeah, I now assume any minor renovation project is exactly the same as a "tear down to the studs" rebuild. When it turns out I don't have to, I feel great!