myBDAsites.com

Hi,

TISCO has an simple estimator for basic building materials:
http://www.tatatiscon.co.in/home-builde ... mator.aspx

Has anyone used it? It says the values are withing +/-25%. What is your experience?

Sanjay

The variation could be even more ,On website its based on IS code for Zone 2 with certain assumptions on Soil Bearing capacity and loading.
If you just go with your contractor or Bar Bender advice , your steel requirements will be very high > 25% and in spite of using heavy bars , and many a times it will not even meet Zone 2 since its a unscientific process.
The actual steel requirements will be given after design by your structural engineer after SBC test and your inputs on Earthquake resistance. Typically its good to upgrade to Zone 3.