Not a construction expert, but I'm inclined to agree. The existing translations appear to be translations of 'dry wall' (two words; = Trockenmauer, ohne Mörtel), not of 'drywall' as one word.
This topic quickly gets rather out of hand, but as far as I can tell, I would support
(1) deleting the one-word spelling for the old sense (or at least listing it second, not first)
dry wall - die Trockenmauer, trockene Mauer
dry wall - trockene Futtermauer (Is this one correct for sure?)
(2) adding translations for the modern sense, e.g.,
drywall (also:) dry wall - Rigips, die Rigipsplatte, der Gipskarton, die Gipskartonplatte, die Gipskartonbauplatte, die Gipswandbauplatte, die Gipskartonwand, die Trockenbauwand, ... (???)
There seem to be almost infinitely many choices in German too, so it may really take a lot of entries to connect each of them to all the English options, or at least, enough to make clear that they're basically all the same stuff. Though some of them seem to refer more to the substance used to construct walls, others to the walls constructed out of that substance -- that's beyond my pay grade, to quote a recent quip.
(3) combining variant spellings to one entry for any that need it, e.g.,
gypsum plasterboard (also:) plaster board - ...
wallboard(also:) wall board - ...
(4) checking whether any of these are chiefly AE (drywall, sheetrock, wallboard?) or chiefly BE (plasterboard?)
(5) noting that both Rigips and Sheetrock (sp?) were apparently originally trademarks, but are now widely used as generic terms (sheetrock in lowercase)
Sorry again that this turns out to be such an unwieldy topic, but maybe it will at least be useful to collect these all in one place for a change. Hope I haven't missed anything. (-;
*f5* re #2: I'm not familiar with 'sheet' in the sense of a section of sheetrock myself, but then I've never personally put up sheetrock. That would certainly also be useful to add.
Technically, I'm wondering if sheetrock might actually be harder than drywall, even though the two are often used interchangeably. If there is any difference, maybe people who know more about the details can help.