Learn Turkish: Çökmüş çatıdan dolayı terk edilmiş binaya girmiyoruz. - We are not entering the abandoned building because of the collapsed roof.

No, it is acting as an adjective! In Turkish, you can attach the -mIş suffix to a verb to turn it into an adjective describing a completed action. Here, çökmek (to collapse) becomes çökmüş (collapsed), describing the noun çatı (roof).

Why does terk edilmiş use edilmiş instead of etmiş?

Terk etmek means 'to abandon'. If we used terk etmiş, it would describe a building that abandoned something. To say 'abandoned' (an action done to the building), we first make the verb passive by changing etmek to edilmek. Then we add the -miş adjective suffix to get terk edilmiş.

Why does the word for roof have the -dan ending in çatıdan dolayı?

The word dolayı (because of / due to) always requires the noun before it to be in the ablative case (the -dan or -den ending). So, 'because of the roof' must be çatıdan dolayı.

Why is the building written as binaya instead of just bina or binayı?