It seems to me, to use the specification of the material will be more logical. I created a proposal page for a tag that will a specify type of concrete facade: https://wiki.openstreetmap.org/wiki/Proposed_features/Extensions_for_concrete_building_material

In fact, quite a few such ugly buildings. They were built a long time ago and most often they are called “khrushchevka”. But modern buildings look more cute. I’ll show you, it’s easy to find such houses. Usually these are residential areas on the outskirts of cities:

St. Petersburg, East- https://www.google.com/maps/@59.9421244,30.4961189,3a,75y,144.84h,116.74t/data=!3m6!1e1!3m4!1swypWo26crSe6J7w4lfY3qg!2e0!7i13312!8i6656?dcr=0

Moscow- https://www.google.com/maps/@55.812014,37.4081866,3a,60y,116.73h,89.72t/data=!3m6!1e1!3m4!1s1cylkg_UQpA2Kez9Z-OlEA!2e0!7i13312!8i6656?dcr=0

St. Petersburg, South-https://www.google.com/maps/@59.8414445,30.3890335,3a,60y,211.43h,110.48t/data=!3m6!1e1!3m4!1sTb2TwIEPF7VRQrJcilx6QA!2e0!7i13312!8i6656?dcr=0

There are such houses in many countries of Eastern Europe.
Kishinev, Moldova: https://www.google.ru/maps/@46.987441,28.8467096,3a,50.5y,45.19h,100.72t/data=!3m8!1e1!3m6!1sAF1QipMGxLgIH58s6QwYCbU9MHzcJmc-TbGjFvHb7-ci!2e10!3e11!6shttps:%2F%2Flh5.googleusercontent.com%2Fp%2FAF1QipMGxLgIH58s6QwYCbU9MHzcJmc-TbGjFvHb7-ci%3Dw203-h100-k-no-pi0-ya232.2003-ro-0-fo100!7i6144!8i3072?dcr=0