Consider the query, "non-glass skyscrapers", which suffers from the same problem.
What do you call a skyscraper like that if you want to refer to it? They exist, but you can't find them using that search term on Google.
What do you call a skyscraper like that if you want to refer to it? They exist, but you can't find them using that search term on Google.
https://www.google.com/search?q=windowless+skyscraper&tbm=is...
https://www.emporis.com/buildings/119453/seattle-tower-seatt...
Windowless is a superset of glassless.
"non-glass skyscraper":
1. No glass used in the exterior construction at all -> implying no windows
2. No glass used in the exterior construction at all -> implying the windows are made out of something other than glass
3. A skyscraper in which glass is not a prominent architectural feature, but the building does contain features like windows and doors that contain glass. (This comment)
That's the full glass buildings returned in your windowless query.