In older buildings it's rarely just the trap. Grease and soap bind to cast-iron roughness 10–15 feet down the branch line. Snaking clears it; recurring clogs usually need the branch replaced.
Yes. Sewer backups are one of the things we take after hours. Waste coming up a floor drain or tub can't wait until morning.
Yes, including below-slab work in basements and out to the curb. We pull the permit and handle the whole job.
If one fixture backs up, it's usually a branch. If multiple fixtures back up at the same time, especially on the lowest floor, it's almost always the main.
We serve Brooklyn and Queens. Fastest response right around our Ridgewood shop.